Winit version 0.30.12

The lint is needed for stable, but is no longer present on nightly, so
silence it for the time being.

.github/CODEOWNERS

@@ -1,6 +1,6 @@
 # Android
-/src/platform/android.rs            @msiglreith @MarijnS95
-/src/platform_impl/android          @msiglreith @MarijnS95
+/src/platform/android.rs            @MarijnS95
+/src/platform_impl/android          @MarijnS95
 
 # iOS
 /src/platform/ios.rs                @madsmtm
@@ -26,8 +26,8 @@
 /src/platform_impl/web              @daxpedda
 
 # Windows
-/src/platform/windows.rs            @msiglreith
-/src/platform_impl/windows          @msiglreith
+/src/platform/windows.rs            @notgull
+/src/platform_impl/windows          @notgull
 
 # Orbital (Redox OS)
 /src/platform/orbital.rs            @jackpot51

.github/workflows/ci.yml

@@ -10,7 +10,7 @@ jobs:
     name: Check formatting
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v4
+    - uses: taiki-e/checkout-action@v1
     - uses: dtolnay/rust-toolchain@nightly
       with:
         components: rustfmt
@@ -22,7 +22,7 @@ jobs:
     runs-on: ubuntu-latest
     timeout-minutes: 30
     steps:
-      - uses: actions/checkout@v4
+      - uses: taiki-e/checkout-action@v1
       - uses: taiki-e/install-action@v2
         with:
           tool: typos-cli
@@ -88,7 +88,7 @@ jobs:
       CMD: ${{ matrix.platform.cmd }}
 
     steps:
-    - uses: actions/checkout@v4
+    - uses: taiki-e/checkout-action@v1
 
     - name: Restore cache of cargo folder
       # We use `restore` and later `save`, so that we can create the key after
@@ -107,7 +107,12 @@ jobs:
 
     - name: Generate lockfile
       # Also updates the crates.io index
-      run: cargo generate-lockfile && cargo update -p ahash --precise 0.8.7 && cargo update -p bumpalo --precise 3.14.0
+      run: |
+           cargo generate-lockfile
+           cargo update -p ahash --precise 0.8.7
+           cargo update -p bumpalo --precise 3.14.0
+           cargo update -p objc2-encode --precise 4.0.3
+           cargo update -p orbclient --precise 0.3.47
 
     - name: Install GCC Multilib
       if: (matrix.platform.os == 'ubuntu-latest') && contains(matrix.platform.target, 'i686')
@@ -220,9 +225,24 @@ jobs:
           - { name: 'Windows', target: x86_64-pc-windows-gnu }
 
     steps:
-    - uses: actions/checkout@v4
-    - uses: EmbarkStudios/cargo-deny-action@v1
+    - uses: taiki-e/checkout-action@v1
+    - uses: EmbarkStudios/cargo-deny-action@v2
       with:
         command: check
         log-level: error
         arguments: --all-features --target ${{ matrix.platform.target }}
+
+  swc:
+    name: Minimize JavaScript
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: taiki-e/checkout-action@v1
+      - name: Install SWC
+        run: sudo npm i -g @swc/cli
+      - name: Run SWC
+        run: |
+          swc src/platform_impl/web/web_sys/worker.js -o src/platform_impl/web/web_sys/worker.min.js
+      - name: Check for diff
+        run: |
+          [[ -z $(git status -s) ]]

.gitignore

@@ -3,8 +3,5 @@ target/
 rls/
 .vscode/
 *~
-*.wasm
-*.ts
-*.js
 #*#
 .DS_Store

.swcrc

@@ -0,0 +1,12 @@
+{
+	"minify": true,
+	"jsc": {
+		"target": "es2022",
+		"minify": {
+			"compress": {
+				"unused": true
+			},
+			"mangle": true
+		}
+	}
+}

CONTRIBUTING.md

@@ -19,6 +19,11 @@ All patches have to be sent on Github as [pull requests][prs]. To simplify your
 life during review it's recommended to check the "give contributors write access
 to the branch" checkbox.
 
+We use unstable Rustfmt options across the project, so please run
+`cargo +nightly fmt` before submitting your work. If you are unable to do so,
+the maintainers can do it for you before merging, just state so in your pull
+request description.
+
 #### Handling review
 
 During the review process certain events could require an action from your side,

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "winit"
-version = "0.30.0"
+version = "0.30.12"
 authors = [
     "The winit contributors",
     "Pierre Krieger <pierre.krieger1708@gmail.com>",
@@ -14,7 +14,17 @@ rust-version.workspace = true
 repository.workspace = true
 license.workspace = true
 edition.workspace = true
-exclude = ["/.cargo"]
+include = [
+    "/build.rs",
+    "/docs",
+    "/examples",
+    "/FEATURES.md",
+    "/LICENSE",
+    "/src",
+    "!/src/platform_impl/web/script",
+    "/src/platform_impl/web/script/**/*.min.js",
+    "/tests",
+]
 
 [package.metadata.docs.rs]
 features = [
@@ -86,11 +96,11 @@ rwh_06 = { package = "raw-window-handle", version = "0.6", features = [
 ], optional = true }
 serde = { workspace = true, optional = true }
 smol_str = "0.2.0"
-tracing = { version = "0.1.40", default_features = false }
+tracing = { version = "0.1.40", default-features = false }
 
 [dev-dependencies]
 image = { version = "0.25.0", default-features = false, features = ["png"] }
-tracing = { version = "0.1.40", default_features = false, features = ["log"] }
+tracing = { version = "0.1.40", default-features = false, features = ["log"] }
 tracing-subscriber = { version = "0.3.18", features = ["env-filter"] }
 winit = { path = ".", features = ["rwh_05"] }
 
@@ -107,8 +117,9 @@ android-activity = "0.6.0"
 ndk = { version = "0.9.0", default-features = false }
 
 [target.'cfg(any(target_os = "ios", target_os = "macos"))'.dependencies]
+block2 = "0.5.1"
 core-foundation = "0.9.3"
-objc2 = "0.5.2"
+objc2 = { version = "0.5.2", features = ["relax-sign-encoding"] }
 
 [target.'cfg(target_os = "macos")'.dependencies]
 core-graphics = "0.23.1"
@@ -116,6 +127,7 @@ core-graphics = "0.23.1"
 [target.'cfg(target_os = "macos")'.dependencies.objc2-foundation]
 version = "0.2.2"
 features = [
+    "block2",
     "dispatch",
     "NSArray",
     "NSAttributedString",
@@ -123,6 +135,7 @@ features = [
     "NSDictionary",
     "NSDistributedNotificationCenter",
     "NSEnumerator",
+    "NSKeyValueObserving",
     "NSNotification",
     "NSObjCRuntime",
     "NSPathUtilities",
@@ -140,6 +153,7 @@ features = [
     "NSApplication",
     "NSBitmapImageRep",
     "NSButton",
+    "NSColor",
     "NSControl",
     "NSCursor",
     "NSDragging",
@@ -166,11 +180,13 @@ features = [
 [target.'cfg(target_os = "ios")'.dependencies.objc2-foundation]
 version = "0.2.2"
 features = [
+    "block2",
     "dispatch",
     "NSArray",
     "NSEnumerator",
     "NSGeometry",
     "NSObjCRuntime",
+    "NSOperation",
     "NSString",
     "NSProcessInfo",
     "NSThread",
@@ -185,6 +201,8 @@ features = [
     "UIEvent",
     "UIGeometry",
     "UIGestureRecognizer",
+    "UITextInput",
+    "UITextInputTraits",
     "UIOrientation",
     "UIPanGestureRecognizer",
     "UIPinchGestureRecognizer",
@@ -216,6 +234,7 @@ features = [
     "Win32_System_Com",
     "Win32_System_LibraryLoader",
     "Win32_System_Ole",
+    "Win32_Security",
     "Win32_System_SystemInformation",
     "Win32_System_SystemServices",
     "Win32_System_Threading",
@@ -235,7 +254,7 @@ features = [
 [target.'cfg(all(unix, not(any(target_os = "redox", target_family = "wasm", target_os = "android", target_os = "ios", target_os = "macos"))))'.dependencies]
 ahash = { version = "0.8.7", features = ["no-rng"], optional = true }
 bytemuck = { version = "1.13.1", default-features = false, optional = true }
-calloop = "0.12.3"
+calloop = "0.13.0"
 libc = "0.2.64"
 memmap2 = { version = "0.9.0", optional = true }
 percent-encoding = { version = "2.0", optional = true }
@@ -245,18 +264,18 @@ rustix = { version = "0.38.4", default-features = false, features = [
     "thread",
     "process",
 ] }
-sctk = { package = "smithay-client-toolkit", version = "0.18.0", default-features = false, features = [
+sctk = { package = "smithay-client-toolkit", version = "0.19.2", default-features = false, features = [
     "calloop",
 ], optional = true }
-sctk-adwaita = { version = "0.9.0", default_features = false, optional = true }
-wayland-backend = { version = "0.3.0", default_features = false, features = [
+sctk-adwaita = { version = "0.10.1", default-features = false, optional = true }
+wayland-backend = { version = "0.3.10", default-features = false, features = [
     "client_system",
 ], optional = true }
-wayland-client = { version = "0.31.1", optional = true }
-wayland-protocols = { version = "0.31.0", features = [
+wayland-client = { version = "0.31.10", optional = true }
+wayland-protocols = { version = "0.32.8", features = [
     "staging",
 ], optional = true }
-wayland-protocols-plasma = { version = "0.2.0", features = [
+wayland-protocols-plasma = { version = "0.3.8", features = [
     "client",
 ], optional = true }
 x11-dl = { version = "2.19.1", optional = true }
@@ -274,57 +293,63 @@ xkbcommon-dl = "0.4.2"
 orbclient = { version = "0.3.47", default-features = false }
 redox_syscall = "0.4.1"
 
-[target.'cfg(target_family = "wasm")'.dependencies.web_sys]
-package = "web-sys"
-version = "0.3.64"
-features = [
-    'AbortController',
-    'AbortSignal',
-    'Blob',
-    'console',
-    'CssStyleDeclaration',
-    'Document',
-    'DomException',
-    'DomRect',
-    'DomRectReadOnly',
-    'Element',
-    'Event',
-    'EventTarget',
-    'FocusEvent',
-    'HtmlCanvasElement',
-    'HtmlElement',
-    'HtmlImageElement',
-    'ImageBitmap',
-    'ImageBitmapOptions',
-    'ImageBitmapRenderingContext',
-    'ImageData',
-    'IntersectionObserver',
-    'IntersectionObserverEntry',
-    'KeyboardEvent',
-    'MediaQueryList',
-    'MessageChannel',
-    'MessagePort',
-    'Node',
-    'PageTransitionEvent',
-    'PointerEvent',
-    'PremultiplyAlpha',
-    'ResizeObserver',
-    'ResizeObserverBoxOptions',
-    'ResizeObserverEntry',
-    'ResizeObserverOptions',
-    'ResizeObserverSize',
-    'VisibilityState',
-    'Window',
-    'WheelEvent',
-    'Url',
-]
-
 [target.'cfg(target_family = "wasm")'.dependencies]
-js-sys = "0.3.64"
+js-sys = "0.3.70"
 pin-project = "1"
-wasm-bindgen = "0.2"
-wasm-bindgen-futures = "0.4"
+wasm-bindgen = "0.2.93"
+wasm-bindgen-futures = "0.4.43"
 web-time = "1"
+web_sys = { package = "web-sys", version = "0.3.70", features = [
+    "AbortController",
+    "AbortSignal",
+    "Blob",
+    "BlobPropertyBag",
+    "console",
+    "CssStyleDeclaration",
+    "Document",
+    "DomException",
+    "DomRect",
+    "DomRectReadOnly",
+    "Element",
+    "Event",
+    "EventTarget",
+    "FocusEvent",
+    "HtmlCanvasElement",
+    "HtmlElement",
+    "HtmlImageElement",
+    "ImageBitmap",
+    "ImageBitmapOptions",
+    "ImageBitmapRenderingContext",
+    "ImageData",
+    "IntersectionObserver",
+    "IntersectionObserverEntry",
+    "KeyboardEvent",
+    "MediaQueryList",
+    "MessageChannel",
+    "MessagePort",
+    "Navigator",
+    "Node",
+    "OrientationLockType",
+    "OrientationType",
+    "PageTransitionEvent",
+    "Permissions",
+    "PermissionState",
+    "PermissionStatus",
+    "PointerEvent",
+    "PremultiplyAlpha",
+    "ResizeObserver",
+    "ResizeObserverBoxOptions",
+    "ResizeObserverEntry",
+    "ResizeObserverOptions",
+    "ResizeObserverSize",
+    "Screen",
+    "ScreenOrientation",
+    "Url",
+    "VisibilityState",
+    "WheelEvent",
+    "Window",
+    "Worker",
+] }
 
 [target.'cfg(all(target_family = "wasm", target_feature = "atomics"))'.dependencies]
 atomic-waker = "1"

README.md

@@ -8,7 +8,7 @@
 
 ```toml
 [dependencies]
-winit = "0.30.0"
+winit = "0.30.12"
 ```
 
 ## [Documentation](https://docs.rs/winit)
@@ -19,7 +19,7 @@ For features _outside_ the scope of winit, see [Are we GUI Yet?](https://arewegu
 
 ## Contact Us
 
-Join us in our [![Matrix](https://img.shields.io/badge/Matrix-%23rust--windowing%3Amatrix.org-blueviolet.svg)](https://matrix.to/#/#rust-windowing:matrix.org) room. If you don't get an answer there, try [![Libera.Chat](https://img.shields.io/badge/libera.chat-%23winit-red.svg)](https://web.libera.chat/#winit).
+Join us in our [![Matrix](https://img.shields.io/badge/Matrix-%23rust--windowing%3Amatrix.org-blueviolet.svg)](https://matrix.to/#/#rust-windowing:matrix.org) room.
 
 The maintainers have a meeting every friday at UTC 15. The meeting notes can be found [here](https://hackmd.io/@winit-meetings).
 
@@ -33,6 +33,10 @@ Winit is designed to be a low-level brick in a hierarchy of libraries. Consequen
 show something on the window you need to use the platform-specific getters provided by winit, or
 another library.
 
+## CONTRIBUTING
+
+For contributing guidelines see [CONTRIBUTING.md](./CONTRIBUTING.md).
+
 ## MSRV Policy
 
 This crate's Minimum Supported Rust Version (MSRV) is **1.70**. Changes to

deny.toml

@@ -1,15 +1,20 @@
-# https://embarkstudios.github.io/cargo-deny/
+# https://embarkstudios.github.io/cargo-deny
 # cargo install cargo-deny
-# cargo update && cargo deny --all-features --log-level error --target aarch64-apple-ios check
+# cargo update && cargo deny --target aarch64-apple-ios check
 # Note: running just `cargo deny check` without a `--target` will result in
 # false positives due to https://github.com/EmbarkStudios/cargo-deny/issues/324
+[graph]
+all-features = true
+exclude-dev = true
 targets = [
     { triple = "aarch64-apple-ios" },
     { triple = "aarch64-linux-android" },
     { triple = "i686-pc-windows-gnu" },
     { triple = "i686-pc-windows-msvc" },
     { triple = "i686-unknown-linux-gnu" },
-    { triple = "wasm32-unknown-unknown" },
+    { triple = "wasm32-unknown-unknown", features = [
+        "atomics",
+    ] },
     { triple = "x86_64-apple-darwin" },
     { triple = "x86_64-apple-ios" },
     { triple = "x86_64-pc-windows-gnu" },
@@ -18,46 +23,58 @@ targets = [
     { triple = "x86_64-unknown-redox" },
 ]
 
-
-[advisories]
-vulnerability = "deny"
-unmaintained = "warn"
-yanked = "deny"
-ignore = []
-
+[licenses]
+allow = [
+    "Apache-2.0",   # https://tldrlegal.com/license/apache-license-2.0-(apache-2.0)
+    "BSD-2-Clause", # https://tldrlegal.com/license/bsd-2-clause-license-(freebsd)
+    "BSD-3-Clause", # https://tldrlegal.com/license/bsd-3-clause-license-(revised)
+    "ISC",          # https://tldrlegal.com/license/isc-license
+    "MIT",          # https://tldrlegal.com/license/mit-license
+    "Unicode-3.0",  # https://spdx.org/licenses/Unicode-3.0.html
+]
+confidence-threshold = 1.0
+private = { ignore = true }
 
 [bans]
 multiple-versions = "deny"
-wildcards = "allow" # at least until https://github.com/EmbarkStudios/cargo-deny/issues/241 is fixed
-deny = []
 skip = [
-    { name = "raw-window-handle" },    # we intentionally have multiple versions of this
-    { name = "bitflags" },             # the ecosystem is in the process of migrating.
-    { name = "libloading" },           # x11rb uses a different version until the next update
+    { crate = "raw-window-handle", reason = "we depend on multiple behind features" },
+    { crate = "bitflags@1", reason = "the ecosystem is in the process of migrating" },
+    { crate = "rustix@0.38", reason = "the ecosystem is in the process of migrating" },
+    { crate = "linux-raw-sys@0.4", reason = "the ecosystem is in the process of migrating" },
 ]
-skip-tree = []
+wildcards = "allow" # at least until https://github.com/EmbarkStudios/cargo-deny/issues/241 is fixed
 
+[bans.build]
+include-archives = true
+interpreted = "deny"
 
-[licenses]
-private = { ignore = true }
-unlicensed = "deny"
-allow-osi-fsf-free = "neither"
-confidence-threshold = 0.92 # We want really high confidence when inferring licenses from text
-copyleft = "deny"
+[[bans.build.bypass]]
 allow = [
-    "Apache-2.0 WITH LLVM-exception", # https://spdx.org/licenses/LLVM-exception.html
-    "Apache-2.0",                     # https://tldrlegal.com/license/apache-license-2.0-(apache-2.0)
-    "BSD-2-Clause",                   # https://tldrlegal.com/license/bsd-2-clause-license-(freebsd)
-    "BSD-3-Clause",                   # https://tldrlegal.com/license/bsd-3-clause-license-(revised)
-    "BSL-1.0",                        # https://tldrlegal.com/license/boost-software-license-1.0-explained
-    "CC0-1.0",                        # https://creativecommons.org/publicdomain/zero/1.0/
-    "ISC",                            # https://tldrlegal.com/license/-isc-license
-    "LicenseRef-UFL-1.0",             # https://tldrlegal.com/license/ubuntu-font-license,-1.0 - no official SPDX, see https://github.com/emilk/egui/issues/2321
-    "MIT-0",                          # https://choosealicense.com/licenses/mit-0/
-    "MIT",                            # https://tldrlegal.com/license/mit-license
-    "MPL-2.0",                        # https://www.mozilla.org/en-US/MPL/2.0/FAQ/ - see Q11. Used by webpki-roots on Linux.
-    "OFL-1.1",                        # https://spdx.org/licenses/OFL-1.1.html
-    "OpenSSL",                        # https://www.openssl.org/source/license.html - used on Linux
-    "Unicode-DFS-2016",               # https://spdx.org/licenses/Unicode-DFS-2016.html
-    "Zlib",                           # https://tldrlegal.com/license/zlib-libpng-license-(zlib)
+    { path = "generate-bindings.sh", checksum = "268ec23248218d779e33853cdc60e2985e70214ff004716cd734270de1f6b561" },
 ]
+crate = "android-activity"
+
+[[bans.build.bypass]]
+allow-globs = ["ci/*", "githooks/*"]
+crate = "zerocopy"
+
+[[bans.build.bypass]]
+allow-globs = ["freetype2/*"]
+crate = "freetype-sys"
+
+[[bans.build.bypass]]
+allow-globs = ["lib/*.a"]
+crate = "windows_i686_gnu"
+
+[[bans.build.bypass]]
+allow-globs = ["lib/*.lib"]
+crate = "windows_i686_msvc"
+
+[[bans.build.bypass]]
+allow-globs = ["lib/*.a"]
+crate = "windows_x86_64_gnu"
+
+[[bans.build.bypass]]
+allow-globs = ["lib/*.lib"]
+crate = "windows_x86_64_msvc"

examples/child_window.rs

@@ -3,75 +3,15 @@
 fn main() -> Result<(), impl std::error::Error> {
     use std::collections::HashMap;
 
-    use winit::application::ApplicationHandler;
     use winit::dpi::{LogicalPosition, LogicalSize, Position};
-    use winit::event::{ElementState, KeyEvent, WindowEvent};
+    use winit::event::{ElementState, Event, KeyEvent, WindowEvent};
     use winit::event_loop::{ActiveEventLoop, EventLoop};
     use winit::raw_window_handle::HasRawWindowHandle;
-    use winit::window::{Window, WindowId};
+    use winit::window::Window;
 
     #[path = "util/fill.rs"]
     mod fill;
 
-    #[derive(Default)]
-    struct Application {
-        parent_window_id: Option<WindowId>,
-        windows: HashMap<WindowId, Window>,
-    }
-
-    impl ApplicationHandler for Application {
-        fn resumed(&mut self, event_loop: &ActiveEventLoop) {
-            let attributes = Window::default_attributes()
-                .with_title("parent window")
-                .with_position(Position::Logical(LogicalPosition::new(0.0, 0.0)))
-                .with_inner_size(LogicalSize::new(640.0f32, 480.0f32));
-            let window = event_loop.create_window(attributes).unwrap();
-
-            println!("Parent window id: {:?})", window.id());
-            self.parent_window_id = Some(window.id());
-
-            self.windows.insert(window.id(), window);
-        }
-
-        fn window_event(
-            &mut self,
-            event_loop: &ActiveEventLoop,
-            window_id: winit::window::WindowId,
-            event: WindowEvent,
-        ) {
-            match event {
-                WindowEvent::CloseRequested => {
-                    self.windows.clear();
-                    event_loop.exit();
-                },
-                WindowEvent::CursorEntered { device_id: _ } => {
-                    // On x11, println when the cursor entered in a window even if the child window
-                    // is created by some key inputs.
-                    // the child windows are always placed at (0, 0) with size (200, 200) in the
-                    // parent window, so we also can see this log when we move
-                    // the cursor around (200, 200) in parent window.
-                    println!("cursor entered in the window {window_id:?}");
-                },
-                WindowEvent::KeyboardInput {
-                    event: KeyEvent { state: ElementState::Pressed, .. },
-                    ..
-                } => {
-                    let parent_window = self.windows.get(&self.parent_window_id.unwrap()).unwrap();
-                    let child_window = spawn_child_window(parent_window, event_loop);
-                    let child_id = child_window.id();
-                    println!("Child window created with id: {child_id:?}");
-                    self.windows.insert(child_id, child_window);
-                },
-                WindowEvent::RedrawRequested => {
-                    if let Some(window) = self.windows.get(&window_id) {
-                        fill::fill_window(window);
-                    }
-                },
-                _ => (),
-            }
-        }
-    }
-
     fn spawn_child_window(parent: &Window, event_loop: &ActiveEventLoop) -> Window {
         let parent = parent.raw_window_handle().unwrap();
         let mut window_attributes = Window::default_attributes()
@@ -85,9 +25,58 @@ fn main() -> Result<(), impl std::error::Error> {
         event_loop.create_window(window_attributes).unwrap()
     }
 
+    let mut windows = HashMap::new();
+
     let event_loop: EventLoop<()> = EventLoop::new().unwrap();
-    let mut app = Application::default();
-    event_loop.run_app(&mut app)
+    let mut parent_window_id = None;
+
+    event_loop.run(move |event: Event<()>, event_loop| {
+        match event {
+            Event::Resumed => {
+                let attributes = Window::default_attributes()
+                    .with_title("parent window")
+                    .with_position(Position::Logical(LogicalPosition::new(0.0, 0.0)))
+                    .with_inner_size(LogicalSize::new(640.0f32, 480.0f32));
+                let window = event_loop.create_window(attributes).unwrap();
+
+                parent_window_id = Some(window.id());
+
+                println!("Parent window id: {parent_window_id:?})");
+                windows.insert(window.id(), window);
+            },
+            Event::WindowEvent { window_id, event } => match event {
+                WindowEvent::CloseRequested => {
+                    windows.clear();
+                    event_loop.exit();
+                },
+                WindowEvent::CursorEntered { device_id: _ } => {
+                    // On x11, println when the cursor entered in a window even if the child window
+                    // is created by some key inputs.
+                    // the child windows are always placed at (0, 0) with size (200, 200) in the
+                    // parent window, so we also can see this log when we move
+                    // the cursor around (200, 200) in parent window.
+                    println!("cursor entered in the window {window_id:?}");
+                },
+                WindowEvent::KeyboardInput {
+                    event: KeyEvent { state: ElementState::Pressed, .. },
+                    ..
+                } => {
+                    let parent_window = windows.get(&parent_window_id.unwrap()).unwrap();
+                    let child_window = spawn_child_window(parent_window, event_loop);
+                    let child_id = child_window.id();
+                    println!("Child window created with id: {child_id:?}");
+                    windows.insert(child_id, child_window);
+                },
+                WindowEvent::RedrawRequested => {
+                    if let Some(window) = windows.get(&window_id) {
+                        fill::fill_window(window);
+                    }
+                },
+                _ => (),
+            },
+            _ => (),
+        }
+    })
 }
 
 #[cfg(all(feature = "rwh_06", not(any(x11_platform, macos_platform, windows_platform))))]

examples/window.rs

@@ -17,9 +17,7 @@ use softbuffer::{Context, Surface};
 
 use winit::application::ApplicationHandler;
 use winit::dpi::{LogicalSize, PhysicalPosition, PhysicalSize};
-use winit::event::{
-    DeviceEvent, DeviceId, Ime, MouseButton, MouseScrollDelta, StartCause, WindowEvent,
-};
+use winit::event::{DeviceEvent, DeviceId, Ime, MouseButton, MouseScrollDelta, WindowEvent};
 use winit::event_loop::{ActiveEventLoop, EventLoop};
 use winit::keyboard::{Key, ModifiersState};
 use winit::window::{
@@ -33,6 +31,8 @@ use winit::platform::macos::{OptionAsAlt, WindowAttributesExtMacOS, WindowExtMac
 use winit::platform::startup_notify::{
     self, EventLoopExtStartupNotify, WindowAttributesExtStartupNotify, WindowExtStartupNotify,
 };
+#[cfg(x11_platform)]
+use winit::platform::x11::WindowAttributesExtX11;
 
 #[path = "util/tracing.rs"]
 mod tracing;
@@ -142,6 +142,28 @@ impl Application {
             window_attributes = window_attributes.with_activation_token(token);
         }
 
+        #[cfg(x11_platform)]
+        match std::env::var("X11_VISUAL_ID") {
+            Ok(visual_id_str) => {
+                info!("Using X11 visual id {visual_id_str}");
+                let visual_id = visual_id_str.parse()?;
+                window_attributes = window_attributes.with_x11_visual(visual_id);
+            },
+            Err(_) => info!("Set the X11_VISUAL_ID env variable to request specific X11 visual"),
+        }
+
+        #[cfg(x11_platform)]
+        match std::env::var("X11_SCREEN_ID") {
+            Ok(screen_id_str) => {
+                info!("Placing the window on X11 screen {screen_id_str}");
+                let screen_id = screen_id_str.parse()?;
+                window_attributes = window_attributes.with_x11_screen(screen_id);
+            },
+            Err(_) => info!(
+                "Set the X11_SCREEN_ID env variable to place the window on non-default screen"
+            ),
+        }
+
         #[cfg(macos_platform)]
         if let Some(tab_id) = _tab_id {
             window_attributes = window_attributes.with_tabbing_identifier(&tab_id);
@@ -214,6 +236,12 @@ impl Application {
             Action::PrintHelp => self.print_help(),
             #[cfg(macos_platform)]
             Action::CycleOptionAsAlt => window.cycle_option_as_alt(),
+            Action::SetTheme(theme) => {
+                window.window.set_theme(theme);
+                // Get the resulting current theme to draw with
+                let actual_theme = theme.or_else(|| window.window.theme()).unwrap_or(Theme::Dark);
+                window.set_draw_theme(actual_theme);
+            },
             #[cfg(macos_platform)]
             Action::CreateNewTab => {
                 let tab_id = window.window.tabbing_identifier();
@@ -305,12 +333,6 @@ impl Application {
 }
 
 impl ApplicationHandler<UserEvent> for Application {
-    fn new_events(&mut self, _event_loop: &ActiveEventLoop, start_cause: StartCause) {
-        if let StartCause::Init = start_cause {
-            info!("Started the event loop");
-        }
-    }
-
     fn user_event(&mut self, _event_loop: &ActiveEventLoop, event: UserEvent) {
         info!("User event: {event:?}");
     }
@@ -328,7 +350,6 @@ impl ApplicationHandler<UserEvent> for Application {
 
         match event {
             WindowEvent::Resized(size) => {
-                info!("Resized({size:?})");
                 window.resize(size);
             },
             WindowEvent::Focused(focused) => {
@@ -343,7 +364,7 @@ impl ApplicationHandler<UserEvent> for Application {
             },
             WindowEvent::ThemeChanged(theme) => {
                 info!("Theme changed to {theme:?}");
-                window.set_theme(theme);
+                window.set_draw_theme(theme);
             },
             WindowEvent::RedrawRequested => {
                 if let Err(err) = window.draw() {
@@ -742,8 +763,8 @@ impl WindowState {
         self.window.request_redraw();
     }
 
-    /// Change the theme.
-    fn set_theme(&mut self, theme: Theme) {
+    /// Change the theme that things are drawn in.
+    fn set_draw_theme(&mut self, theme: Theme) {
         self.theme = theme;
         self.window.request_redraw();
     }
@@ -893,6 +914,7 @@ enum Action {
     ShowWindowMenu,
     #[cfg(macos_platform)]
     CycleOptionAsAlt,
+    SetTheme(Option<Theme>),
     #[cfg(macos_platform)]
     CreateNewTab,
     RequestResize,
@@ -924,6 +946,9 @@ impl Action {
             Action::ShowWindowMenu => "Show window menu",
             #[cfg(macos_platform)]
             Action::CycleOptionAsAlt => "Cycle option as alt mode",
+            Action::SetTheme(None) => "Change to the system theme",
+            Action::SetTheme(Some(Theme::Light)) => "Change to a light theme",
+            Action::SetTheme(Some(Theme::Dark)) => "Change to a dark theme",
             #[cfg(macos_platform)]
             Action::CreateNewTab => "Create new tab",
             Action::RequestResize => "Request a resize",
@@ -1068,6 +1093,10 @@ const KEY_BINDINGS: &[Binding<&'static str>] = &[
         Action::AnimationCustomCursor,
     ),
     Binding::new("Z", ModifiersState::CONTROL, Action::ToggleCursorVisibility),
+    // K.
+    Binding::new("K", ModifiersState::empty(), Action::SetTheme(None)),
+    Binding::new("K", ModifiersState::SUPER, Action::SetTheme(Some(Theme::Light))),
+    Binding::new("K", ModifiersState::CONTROL, Action::SetTheme(Some(Theme::Dark))),
     #[cfg(macos_platform)]
     Binding::new("T", ModifiersState::SUPER, Action::CreateNewTab),
     #[cfg(macos_platform)]

src/changelog/unreleased.md

@@ -12,7 +12,6 @@ on how to add them:
 ### Added
 
 - Add `Window::turbo()`, implemented on X11, Wayland, and Web.
-- Add traits `EventLoopExtWayland` and `EventLoopExtX11`, providing methods `is_wayland` and `is_x11` on `EventLoop`.
 - On X11, add `Window::some_rare_api`.
 - On X11, add `Window::even_more_rare_api`.
 - On Wayland, add `Window::common_api`.
@@ -41,18 +40,6 @@ changelog entry.
 
 ## Unreleased
 
-### Added
-
-- Reexport `raw-window-handle` versions 0.4 and 0.5 as `raw_window_handle_04` and `raw_window_handle_05`.
-- Implement `ApplicationHandler` for `&mut` references and heap allocations to something that implements `ApplicationHandler`.
-
-### Removed
-
-- Remove `EventLoop::run`.
-- Remove `EventLoopExtRunOnDemand::run_on_demand`.
-- Remove `EventLoopExtPumpEvents::pump_events`.
-
 ### Fixed
 
-- On macOS, fix panic on exit when dropping windows outside the event loop.
-- On macOS, fix window dragging glitches when dragging across a monitor boundary with different scale factor.
+- On macOS, fix crash on macOS 26 by using objc2's `relax-sign-encoding` feature.

src/changelog/v0.20.md

@@ -137,7 +137,7 @@
 
 - On X11, non-resizable windows now have maximize explicitly disabled.
 - On Windows, support paths longer than MAX_PATH (260 characters) in `WindowEvent::DroppedFile`
-and `WindowEvent::HoveredFile`.
+  and `WindowEvent::HoveredFile`.
 - On Mac, implement `DeviceEvent::Button`.
 - Change `Event::Suspended(true / false)` to `Event::Suspended` and `Event::Resumed`.
 - On X11, fix sanity check which checks that a monitor's reported width and height (in millimeters) are non-zero when calculating the DPI factor.

src/changelog/v0.29.md

@@ -250,7 +250,7 @@
 - On Web, fix some `WindowBuilder` methods doing nothing.
 - On Web, fix some `Window` methods using incorrect HTML attributes instead of CSS properties.
 - On Web, fix the bfcache by not using the `beforeunload` event and map bfcache loading/unloading to `Suspended`/`Resumed` events.
-- On Web, fix touch input not gaining or loosing focus.
+- On Web, fix touch input not gaining or losing focus.
 - On Web, fix touch location to be as accurate as mouse position.
 - On Web, handle coalesced pointer events, which increases the resolution of pointer inputs.
 - On Web, implement `Window::focus_window()`.

src/changelog/v0.30.md

@@ -1,3 +1,177 @@
+## 0.30.12
+
+### Fixed
+
+- On macOS, fix crash on macOS 26 by using objc2's `relax-sign-encoding` feature.
+
+## 0.30.11
+
+### Fixed
+
+- On Windows, fixed crash in should_apps_use_dark_mode() for Windows versions < 17763.
+- On Wayland, fixed `pump_events` driven loop deadlocking when loop was not drained before exit.
+
+## 0.30.10
+
+### Added
+
+- On Windows, add `IconExtWindows::from_resource_name`.
+- On Windows, add `CursorGrabMode::Locked`.
+- On Wayland, add `WindowExtWayland::xdg_toplevel`.
+
+### Changed
+
+- On macOS, no longer need control of the main `NSApplication` class (which means you can now override it yourself).
+- On iOS, remove custom application delegates. You are now allowed to override the
+  application delegate yourself.
+- On iOS, no longer act as-if the application successfully open all URLs. Override
+  `application:didFinishLaunchingWithOptions:` and provide the desired behaviour yourself.
+
+### Fixed
+
+- On Windows, fixed ~500 ms pause when clicking the title bar during continuous redraw.
+- On macOS, `WindowExtMacOS::set_simple_fullscreen` now honors `WindowExtMacOS::set_borderless_game`
+- On X11 and Wayland, fixed pump_events with `Some(Duration::Zero)` blocking with `Wait` polling mode
+- On Wayland, fixed a crash when consequently calling `set_cursor_grab` without pointer focus.
+- On Wayland, ensure that external event loop is woken-up when using pump_events and integrating via `FD`.
+- On Wayland, apply fractional scaling to custom cursors.
+- On macOS, fixed `run_app_on_demand` returning without closing open windows.
+- On macOS, fixed `VideoMode::refresh_rate_millihertz` for fractional refresh rates.
+- On macOS, store monitor handle to avoid panics after going in/out of sleep.
+- On macOS, allow certain invalid monitor handles and return `None` instead of panicking.
+- On Windows, fixed `Ime::Preedit` cursor offset calculation.
+
+## 0.30.9
+
+### Changed
+
+- On Wayland, no longer send an explicit clearing `Ime::Preedit` just prior to a new `Ime::Preedit`.
+
+### Fixed
+
+- On X11, fix crash with uim.
+- On X11, fix modifiers for keys that were sent by the same X11 request.
+- On iOS, fix high CPU usage even when using `ControlFlow::Wait`.
+
+## 0.30.8
+
+### Added
+
+- `ActivationToken::from_raw` and `ActivationToken::into_raw`.
+- On X11, add a workaround for disabling IME on GNOME.
+
+### Fixed
+
+- On Windows, fixed the event loop not waking on accessibility requests.
+- On X11, fixed cursor grab mode state tracking on error.
+
+## 0.30.7
+
+### Fixed
+
+- On X11, fixed KeyboardInput delivered twice when IME enabled.
+
+## 0.30.6
+
+### Added
+
+- On macOS, add `WindowExtMacOS::set_borderless_game` and `WindowAttributesExtMacOS::with_borderless_game`
+  to fully disable the menu bar and dock in Borderless Fullscreen as commonly done in games.
+- On X11, the `window` example now understands the `X11_VISUAL_ID` and `X11_SCREEN_ID` env
+  variables to test the respective modifiers of window creation.
+- On Android, the soft keyboard can now be shown using `Window::set_ime_allowed`.
+- Add basic iOS IME support. The soft keyboard can now be shown using `Window::set_ime_allowed`.
+
+### Fixed
+
+- On macOS, fix `WindowEvent::Moved` sometimes being triggered unnecessarily on resize.
+- On macOS, package manifest definitions of `LSUIElement` will no longer be overridden with the
+  default activation policy, unless explicitly provided during initialization.
+- On macOS, fix crash when calling `drag_window()` without a left click present.
+- On X11, key events forward to IME anyway, even when it's disabled.
+- On Windows, make `ControlFlow::WaitUntil` work more precisely using `CREATE_WAITABLE_TIMER_HIGH_RESOLUTION`.
+- On X11, creating windows on screen that is not the first one (e.g. `DISPLAY=:0.1`) works again.
+- On X11, creating windows while passing `with_x11_screen(non_default_screen)` works again.
+- On X11, fix XInput handling that prevented a new window from getting the focus in some cases.
+- On macOS, fix crash when pressing Caps Lock in certain configurations.
+- On iOS, fixed `MonitorHandle`'s `PartialEq` and `Hash` implementations.
+- On macOS, fixed undocumented cursors (e.g. zoom, resize, help) always appearing to be invalid and falling back to the default cursor.
+
+## 0.30.5
+
+### Added
+
+- Add `ActiveEventLoop::system_theme()`, returning the current system theme.
+- On Web, implement `Error` for `platform::web::CustomCursorError`.
+- On Android, add `{Active,}EventLoopExtAndroid::android_app()` to access the app used to create the loop.
+
+### Fixed
+
+- On MacOS, fix building with `feature = "rwh_04"`.
+- On Web, pen events are now routed through to `WindowEvent::Cursor*`.
+- On macOS, fix panic when releasing not available monitor.
+- On MacOS, return the system theme in `Window::theme()` if no theme override is set.
+
+## 0.30.4
+
+### Changed
+
+- `DeviceId::dummy()` and `WindowId::dummy()` are no longer marked `unsafe`.
+
+### Fixed
+
+- On Wayland, avoid crashing when compositor is misbehaving.
+- On Web, fix `WindowEvent::Resized` not using `requestAnimationFrame` when sending
+  `WindowEvent::RedrawRequested` and also potentially causing `WindowEvent::RedrawRequested`
+  to not be de-duplicated.
+- Account for different browser engine implementations of pointer movement coordinate space.
+
+## 0.30.3
+
+### Added
+
+- On Web, add `EventLoopExtWebSys::(set_)poll_strategy()` to allow setting
+  control flow strategies before starting the event loop.
+- On Web, add `WaitUntilStrategy`, which allows to set different strategies for
+  `ControlFlow::WaitUntil`. By default the Prioritized Task Scheduling API is
+  used, with a fallback to `setTimeout()` with a trick to circumvent throttling
+  to 4ms. But an option to use a Web worker to schedule the timer is available
+  as well, which commonly prevents any throttling when the window is not focused.
+
+### Changed
+
+- On macOS, set the window theme on the `NSWindow` instead of application-wide.
+
+### Fixed
+
+- On X11, build on arm platforms.
+- On macOS, fixed `WindowBuilder::with_theme` not having any effect on the window.
+
+## 0.30.2
+
+### Fixed
+
+- On Web, fix `EventLoopProxy::send_event()` triggering event loop immediately
+  when not called from inside the event loop. Now queues a microtask instead.
+- On Web, stop overwriting default cursor with `CursorIcon::Default`.
+- On Web, prevent crash when using `InnerSizeWriter::request_inner_size()`.
+- On macOS, fix not working opacity for entire window.
+
+## 0.30.1
+
+### Added
+
+- Reexport `raw-window-handle` versions 0.4 and 0.5 as `raw_window_handle_04` and `raw_window_handle_05`.
+- Implement `ApplicationHandler` for `&mut` references and heap allocations to something that implements `ApplicationHandler`.
+
+### Fixed
+
+- On macOS, fix panic on exit when dropping windows outside the event loop.
+- On macOS, fix window dragging glitches when dragging across a monitor boundary with different scale factor.
+- On macOS, fix the range in `Ime::Preedit`.
+- On macOS, use the system's internal mechanisms for queuing events.
+- On macOS, handle events directly instead of queuing when possible.
+
 ## 0.30.0
 
 ### Added
@@ -65,7 +239,7 @@
   `Fn`. The semantics are mostly the same, given that the capture list of the
   closure is your new `State`. Consider the following code:
 
-  ```rust,no_run,ignore
+  ```rust,no_run
   use winit::event::Event;
   use winit::event_loop::EventLoop;
   use winit::window::Window;

src/changelog/v0.9.md

@@ -3,20 +3,20 @@
 - Added event `WindowEvent::HiDPIFactorChanged`.
 - Added method `MonitorId::get_hidpi_factor`.
 - Deprecated `get_inner_size_pixels` and `get_inner_size_points` methods of `Window` in favor of
-`get_inner_size`.
+  `get_inner_size`.
 - **Breaking:** `EventsLoop` is `!Send` and `!Sync` because of platform-dependant constraints,
   but `Window`, `WindowId`, `DeviceId` and `MonitorId` guaranteed to be `Send`.
 - `MonitorId::get_position` now returns `(i32, i32)` instead of `(u32, u32)`.
 - Rewrite of the wayland backend to use wayland-client-0.11
 - Support for dead keys on wayland for keyboard utf8 input
 - Monitor enumeration on Windows is now implemented using `EnumDisplayMonitors` instead of
-`EnumDisplayDevices`. This changes the value returned by `MonitorId::get_name()`.
+  `EnumDisplayDevices`. This changes the value returned by `MonitorId::get_name()`.
 - On Windows added `MonitorIdExt::hmonitor` method
 - Impl `Clone` for `EventsLoopProxy`
 - `EventsLoop::get_primary_monitor()` on X11 will fallback to any available monitor if no primary is found
 - Support for touch event on wayland
 - `WindowEvent`s `MouseMoved`, `MouseEntered`, and `MouseLeft` have been renamed to
-`CursorMoved`, `CursorEntered`, and `CursorLeft`.
+  `CursorMoved`, `CursorEntered`, and `CursorLeft`.
 - New `DeviceEvent`s added, `MouseMotion` and `MouseWheel`.
 - Send `CursorMoved` event after `CursorEntered` and `Focused` events.
 - Add support for `ModifiersState`, `MouseMove`, `MouseInput`, `MouseMotion` for emscripten backend.

src/event.rs

@@ -389,6 +389,8 @@ pub enum WindowEvent {
     /// Applications might wish to react to this to change the theme of the content of the window
     /// when the system changes the window theme.
     ///
+    /// This only reports a change if the window theme was not overridden by [`Window::set_theme`].
+    ///
     /// ## Platform-specific
     ///
     /// - **iOS / Android / X11 / Wayland / Orbital:** Unsupported.
@@ -447,16 +449,13 @@ pub struct DeviceId(pub(crate) platform_impl::DeviceId);
 impl DeviceId {
     /// Returns a dummy id, useful for unit testing.
     ///
-    /// # Safety
+    /// # Notes
     ///
     /// The only guarantee made about the return value of this function is that
     /// it will always be equal to itself and to future values returned by this function.
     /// No other guarantees are made. This may be equal to a real `DeviceId`.
-    ///
-    /// **Passing this into a winit function will result in undefined behavior.**
-    pub const unsafe fn dummy() -> Self {
-        #[allow(unused_unsafe)]
-        DeviceId(unsafe { platform_impl::DeviceId::dummy() })
+    pub const fn dummy() -> Self {
+        DeviceId(platform_impl::DeviceId::dummy())
     }
 }
 
@@ -533,11 +532,11 @@ pub struct KeyEvent {
     /// ## Caveats
     ///
     /// - Certain niche hardware will shuffle around physical key positions, e.g. a keyboard that
-    /// implements DVORAK in hardware (or firmware)
+    ///   implements DVORAK in hardware (or firmware)
     /// - Your application will likely have to handle keyboards which are missing keys that your
-    /// own keyboard has.
+    ///   own keyboard has.
     /// - Certain `KeyCode`s will move between a couple of different positions depending on what
-    /// layout the keyboard was manufactured to support.
+    ///   layout the keyboard was manufactured to support.
     ///
     ///  **Because of these caveats, it is important that you provide users with a way to configure
     ///  most (if not all) keybinds in your application.**
@@ -559,8 +558,7 @@ pub struct KeyEvent {
     ///
     /// This has two use cases:
     /// - Allows querying whether the current input is a Dead key.
-    /// - Allows handling key-bindings on platforms which don't
-    /// support [`key_without_modifiers`].
+    /// - Allows handling key-bindings on platforms which don't support [`key_without_modifiers`].
     ///
     /// If you use this field (or [`key_without_modifiers`] for that matter) for keyboard
     /// shortcuts, **it is important that you provide users with a way to configure your
@@ -568,8 +566,8 @@ pub struct KeyEvent {
     /// incompatible keyboard layout.**
     ///
     /// ## Platform-specific
-    /// - **Web:** Dead keys might be reported as the real key instead
-    /// of `Dead` depending on the browser/OS.
+    /// - **Web:** Dead keys might be reported as the real key instead of `Dead` depending on the
+    ///   browser/OS.
     ///
     /// [`key_without_modifiers`]: crate::platform::modifier_supplement::KeyEventExtModifierSupplement::key_without_modifiers
     pub logical_key: keyboard::Key,
@@ -851,8 +849,8 @@ pub struct Touch {
     ///
     /// - Only available on **iOS** 9.0+, **Windows** 8+, **Web**, and **Android**.
     /// - **Android**: This will never be [None]. If the device doesn't support pressure
-    /// sensitivity, force will either be 0.0 or 1.0. Also see the
-    /// [android documentation](https://developer.android.com/reference/android/view/MotionEvent#AXIS_PRESSURE).
+    ///   sensitivity, force will either be 0.0 or 1.0. Also see the
+    ///   [android documentation](https://developer.android.com/reference/android/view/MotionEvent#AXIS_PRESSURE).
     pub force: Option<Force>,
     /// Unique identifier of a finger.
     pub id: u64,
@@ -1019,7 +1017,7 @@ mod tests {
         ($closure:expr) => {{
             #[allow(unused_mut)]
             let mut x = $closure;
-            let did = unsafe { event::DeviceId::dummy() };
+            let did = event::DeviceId::dummy();
 
             #[allow(deprecated)]
             {
@@ -1029,7 +1027,7 @@ mod tests {
                 use crate::window::WindowId;
 
                 // Mainline events.
-                let wid = unsafe { WindowId::dummy() };
+                let wid = WindowId::dummy();
                 x(UserEvent(()));
                 x(NewEvents(event::StartCause::Init));
                 x(AboutToWait);
@@ -1154,11 +1152,11 @@ mod tests {
     #[test]
     fn ensure_attrs_do_not_panic() {
         foreach_event!(|event: event::Event<()>| {
-            let _ = format!("{:?}", event);
+            let _ = format!("{event:?}");
         });
         let _ = event::StartCause::Init.clone();
 
-        let did = unsafe { crate::event::DeviceId::dummy() }.clone();
+        let did = crate::event::DeviceId::dummy().clone();
         HashSet::new().insert(did);
         let mut set = [did, did, did];
         set.sort_unstable();

src/event_loop.rs

@@ -20,9 +20,10 @@ use web_time::{Duration, Instant};
 
 use crate::application::ApplicationHandler;
 use crate::error::{EventLoopError, OsError};
+use crate::event::Event;
 use crate::monitor::MonitorHandle;
 use crate::platform_impl;
-use crate::window::{CustomCursor, CustomCursorSource, Window, WindowAttributes};
+use crate::window::{CustomCursor, CustomCursorSource, Theme, Window, WindowAttributes};
 
 /// Provides a way to retrieve events from the system and from the windows that were registered to
 /// the events loop.
@@ -151,7 +152,6 @@ impl fmt::Debug for ActiveEventLoop {
 /// Defaults to [`Wait`].
 ///
 /// [`Wait`]: Self::Wait
-/// [`Event::AboutToWait`]: crate::event::Event::AboutToWait
 #[derive(Copy, Clone, Debug, Default, PartialEq, Eq)]
 pub enum ControlFlow {
     /// When the current loop iteration finishes, immediately begin a new iteration regardless of
@@ -209,110 +209,6 @@ impl EventLoop<()> {
     }
 }
 
-#[cfg(debug_assertions)]
-pub(crate) fn ensure_event_order<'a, T: 'static>(
-    handler: impl ApplicationHandler<T> + 'a,
-) -> impl ApplicationHandler<T> + 'a {
-    use crate::event::{DeviceEvent, DeviceId, StartCause, WindowEvent};
-    use crate::window::WindowId;
-
-    #[derive(Default, Debug, PartialEq, Eq, Clone)]
-    enum State {
-        #[default]
-        NotRunning,
-        Suspended,
-        Running,
-        Waiting,
-    }
-
-    impl State {
-        #[track_caller]
-        fn expect(&self, expected: State) {
-            if *self != expected {
-                tracing::error!("expected state to be {expected:?}, found {self:?}");
-            }
-        }
-
-        #[track_caller]
-        fn transition(&mut self, from: State, to: State) {
-            if *self != from {
-                tracing::error!(
-                    "invalid state transition to {to:?}. Expected {from:?}, found {self:?}"
-                );
-            }
-            *self = to;
-        }
-    }
-
-    struct EnsureEventOrder<A> {
-        inner: A,
-        state: State,
-    }
-
-    impl<A: ApplicationHandler<T>, T: 'static> ApplicationHandler<T> for EnsureEventOrder<A> {
-        fn new_events(&mut self, event_loop: &ActiveEventLoop, cause: StartCause) {
-            match cause {
-                StartCause::Init => self.state.transition(State::NotRunning, State::Suspended),
-                _ => self.state.transition(State::Waiting, State::Running),
-            }
-
-            self.inner.new_events(event_loop, cause);
-        }
-
-        fn resumed(&mut self, event_loop: &ActiveEventLoop) {
-            self.state.transition(State::Suspended, State::Running);
-            self.inner.resumed(event_loop);
-        }
-
-        fn suspended(&mut self, event_loop: &ActiveEventLoop) {
-            self.state.transition(State::Running, State::Suspended);
-            self.inner.suspended(event_loop);
-        }
-
-        fn about_to_wait(&mut self, event_loop: &ActiveEventLoop) {
-            self.state.transition(State::Running, State::Waiting);
-            self.inner.about_to_wait(event_loop);
-        }
-
-        fn exiting(&mut self, event_loop: &ActiveEventLoop) {
-            self.state.transition(State::Suspended, State::NotRunning);
-            self.inner.exiting(event_loop);
-        }
-
-        fn user_event(&mut self, event_loop: &ActiveEventLoop, event: T) {
-            self.state.expect(State::Running);
-            self.inner.user_event(event_loop, event);
-        }
-
-        fn window_event(
-            &mut self,
-            event_loop: &ActiveEventLoop,
-            window_id: WindowId,
-            event: WindowEvent,
-        ) {
-            self.state.expect(State::Running);
-            self.inner.window_event(event_loop, window_id, event);
-        }
-
-        fn device_event(
-            &mut self,
-            event_loop: &ActiveEventLoop,
-            device_id: DeviceId,
-            event: DeviceEvent,
-        ) {
-            self.state.expect(State::Running);
-            self.inner.device_event(event_loop, device_id, event);
-        }
-
-        fn memory_warning(&mut self, event_loop: &ActiveEventLoop) {
-            // TODO: What states are allowed when receiving this?
-            self.inner.memory_warning(event_loop);
-        }
-    }
-
-    EnsureEventOrder { inner: handler, state: State::NotRunning }
-}
-
 impl<T> EventLoop<T> {
     /// Start building a new event loop, with the given type as the user event
     /// type.
@@ -320,6 +216,21 @@ impl<T> EventLoop<T> {
         EventLoopBuilder { platform_specific: Default::default(), _p: PhantomData }
     }
 
+    /// See [`run_app`].
+    ///
+    /// [`run_app`]: Self::run_app
+    #[inline]
+    #[deprecated = "use `EventLoop::run_app` instead"]
+    #[cfg(not(all(web_platform, target_feature = "exception-handling")))]
+    pub fn run<F>(self, event_handler: F) -> Result<(), EventLoopError>
+    where
+        F: FnMut(Event<T>, &ActiveEventLoop),
+    {
+        let _span = tracing::debug_span!("winit::EventLoop::run").entered();
+
+        self.event_loop.run(event_handler)
+    }
+
     /// Run the application with the event loop on the calling thread.
     ///
     /// See the [`set_control_flow()`] docs on how to change the event loop's behavior.
@@ -351,9 +262,7 @@ impl<T> EventLoop<T> {
     #[inline]
     #[cfg(not(all(web_platform, target_feature = "exception-handling")))]
     pub fn run_app<A: ApplicationHandler<T>>(self, app: &mut A) -> Result<(), EventLoopError> {
-        #[cfg(debug_assertions)]
-        let app = &mut ensure_event_order(app);
-        self.event_loop.run_app(app)
+        self.event_loop.run(|event, event_loop| dispatch_event_for_app(app, event_loop, event))
     }
 
     /// Creates an [`EventLoopProxy`] that can be used to dispatch user events
@@ -528,6 +437,17 @@ impl ActiveEventLoop {
         self.p.listen_device_events(allowed);
     }
 
+    /// Returns the current system theme.
+    ///
+    /// Returns `None` if it cannot be determined on the current platform.
+    ///
+    /// ## Platform-specific
+    ///
+    /// - **iOS / Android / Wayland / x11 / Orbital:** Unsupported.
+    pub fn system_theme(&self) -> Option<Theme> {
+        self.p.system_theme()
+    }
+
     /// Sets the [`ControlFlow`].
     pub fn set_control_flow(&self, control_flow: ControlFlow) {
         self.p.set_control_flow(control_flow)
@@ -540,7 +460,7 @@ impl ActiveEventLoop {
 
     /// This exits the event loop.
     ///
-    /// See [`LoopExiting`][crate::event::Event::LoopExiting].
+    /// See [`LoopExiting`][Event::LoopExiting].
     pub fn exit(&self) {
         let _span = tracing::debug_span!("winit::ActiveEventLoop::exit",).entered();
 
@@ -581,7 +501,7 @@ unsafe impl rwh_05::HasRawDisplayHandle for ActiveEventLoop {
 
 /// A proxy for the underlying display handle.
 ///
-/// The purpose of this type is to provide a cheaply clonable handle to the underlying
+/// The purpose of this type is to provide a cheaply cloneable handle to the underlying
 /// display handle. This is often used by graphics APIs to connect to the underlying APIs.
 /// It is difficult to keep a handle to the [`EventLoop`] type or the [`ActiveEventLoop`]
 /// type. In contrast, this type involves no lifetimes and can be persisted for as long as
@@ -709,3 +629,23 @@ impl AsyncRequestSerial {
         Self { serial }
     }
 }
+
+/// Shim for various run APIs.
+#[inline(always)]
+pub(crate) fn dispatch_event_for_app<T: 'static, A: ApplicationHandler<T>>(
+    app: &mut A,
+    event_loop: &ActiveEventLoop,
+    event: Event<T>,
+) {
+    match event {
+        Event::NewEvents(cause) => app.new_events(event_loop, cause),
+        Event::WindowEvent { window_id, event } => app.window_event(event_loop, window_id, event),
+        Event::DeviceEvent { device_id, event } => app.device_event(event_loop, device_id, event),
+        Event::UserEvent(event) => app.user_event(event_loop, event),
+        Event::Suspended => app.suspended(event_loop),
+        Event::Resumed => app.resumed(event_loop),
+        Event::AboutToWait => app.about_to_wait(event_loop),
+        Event::LoopExiting => app.exiting(event_loop),
+        Event::MemoryWarning => app.memory_warning(event_loop),
+    }
+}

src/keyboard.rs

@@ -1232,7 +1232,7 @@ pub enum NamedKey {
     Dimmer,
     /// Swap video sources. (`VK_DISPLAY_SWAP`)
     DisplaySwap,
-    /// Select Digital Video Rrecorder. (`KEYCODE_DVR`)
+    /// Select Digital Video Recorder. (`KEYCODE_DVR`)
     DVR,
     /// Exit the current application. (`VK_EXIT`)
     Exit,

src/lib.rs

@@ -7,7 +7,12 @@
 //!
 //! ```no_run
 //! use winit::event_loop::EventLoop;
-//! let event_loop = EventLoop::new().unwrap();
+//!
+//! # // Intentionally use `fn main` for clarity
+//! fn main() {
+//!     let event_loop = EventLoop::new().unwrap();
+//!     // ...
+//! }
 //! ```
 //!
 //! Then you create a [`Window`] with [`create_window`].
@@ -84,19 +89,22 @@
 //!     }
 //! }
 //!
-//! let event_loop = EventLoop::new().unwrap();
+//! # // Intentionally use `fn main` for clarity
+//! fn main() {
+//!     let event_loop = EventLoop::new().unwrap();
 //!
-//! // ControlFlow::Poll continuously runs the event loop, even if the OS hasn't
-//! // dispatched any events. This is ideal for games and similar applications.
-//! event_loop.set_control_flow(ControlFlow::Poll);
+//!     // ControlFlow::Poll continuously runs the event loop, even if the OS hasn't
+//!     // dispatched any events. This is ideal for games and similar applications.
+//!     event_loop.set_control_flow(ControlFlow::Poll);
 //!
-//! // ControlFlow::Wait pauses the event loop if no events are available to process.
-//! // This is ideal for non-game applications that only update in response to user
-//! // input, and uses significantly less power/CPU time than ControlFlow::Poll.
-//! event_loop.set_control_flow(ControlFlow::Wait);
+//!     // ControlFlow::Wait pauses the event loop if no events are available to process.
+//!     // This is ideal for non-game applications that only update in response to user
+//!     // input, and uses significantly less power/CPU time than ControlFlow::Poll.
+//!     event_loop.set_control_flow(ControlFlow::Wait);
 //!
-//! let mut app = App::default();
-//! event_loop.run_app(&mut app);
+//!     let mut app = App::default();
+//!     event_loop.run_app(&mut app);
+//! }
 //! ```
 //!
 //! [`WindowEvent`] has a [`WindowId`] member. In multi-window environments, it should be
@@ -157,7 +165,6 @@
 //! [`Window`]: window::Window
 //! [`WindowId`]: window::WindowId
 //! [`WindowAttributes`]: window::WindowAttributes
-//! [window_new]: window::Window::new
 //! [`create_window`]: event_loop::ActiveEventLoop::create_window
 //! [`Window::id()`]: window::Window::id
 //! [`WindowEvent`]: event::WindowEvent
@@ -177,6 +184,9 @@
 // doc
 #![cfg_attr(docsrs, feature(doc_auto_cfg, doc_cfg_hide), doc(cfg_hide(doc, docsrs)))]
 #![allow(clippy::missing_safety_doc)]
+#![warn(clippy::uninlined_format_args)]
+// TODO: wasm-binding needs to be updated for that to be resolved, for now just silence it.
+#![cfg_attr(web_platform, allow(unknown_lints, renamed_and_removed_lints, wasm_c_abi))]
 
 #[cfg(feature = "rwh_04")]
 pub use rwh_04 as raw_window_handle_04;

src/platform/android.rs

@@ -62,7 +62,7 @@
 //! If your application is currently based on `NativeActivity` via the `ndk-glue` crate and building
 //! with `cargo apk`, then the minimal changes would be:
 //! 1. Remove `ndk-glue` from your `Cargo.toml`
-//! 2. Enable the `"android-native-activity"` feature for Winit: `winit = { version = "0.30.0",
+//! 2. Enable the `"android-native-activity"` feature for Winit: `winit = { version = "0.30.12",
 //!    features = [ "android-native-activity" ] }`
 //! 3. Add an `android_main` entrypoint (as above), instead of using the '`[ndk_glue::main]` proc
 //!    macro from `ndk-macros` (optionally add a dependency on `android_logger` and initialize
@@ -76,12 +76,22 @@ use crate::window::{Window, WindowAttributes};
 use self::activity::{AndroidApp, ConfigurationRef, Rect};
 
 /// Additional methods on [`EventLoop`] that are specific to Android.
-pub trait EventLoopExtAndroid {}
+pub trait EventLoopExtAndroid {
+    /// Get the [`AndroidApp`] which was used to create this event loop.
+    fn android_app(&self) -> &AndroidApp;
+}
 
-impl<T> EventLoopExtAndroid for EventLoop<T> {}
+impl<T> EventLoopExtAndroid for EventLoop<T> {
+    fn android_app(&self) -> &AndroidApp {
+        &self.event_loop.android_app
+    }
+}
 
 /// Additional methods on [`ActiveEventLoop`] that are specific to Android.
-pub trait ActiveEventLoopExtAndroid {}
+pub trait ActiveEventLoopExtAndroid {
+    /// Get the [`AndroidApp`] which was used to create this event loop.
+    fn android_app(&self) -> &AndroidApp;
+}
 
 /// Additional methods on [`Window`] that are specific to Android.
 pub trait WindowExtAndroid {
@@ -100,7 +110,11 @@ impl WindowExtAndroid for Window {
     }
 }
 
-impl ActiveEventLoopExtAndroid for ActiveEventLoop {}
+impl ActiveEventLoopExtAndroid for ActiveEventLoop {
+    fn android_app(&self) -> &AndroidApp {
+        &self.p.app
+    }
+}
 
 /// Additional methods on [`WindowAttributes`] that are specific to Android.
 pub trait WindowAttributesExtAndroid {}
@@ -108,9 +122,9 @@ pub trait WindowAttributesExtAndroid {}
 impl WindowAttributesExtAndroid for WindowAttributes {}
 
 pub trait EventLoopBuilderExtAndroid {
-    /// Associates the `AndroidApp` that was passed to `android_main()` with the event loop
+    /// Associates the [`AndroidApp`] that was passed to `android_main()` with the event loop
     ///
-    /// This must be called on Android since the `AndroidApp` is not global state.
+    /// This must be called on Android since the [`AndroidApp`] is not global state.
     fn with_android_app(&mut self, app: AndroidApp) -> &mut Self;
 
     /// Calling this will mark the volume keys to be manually handled by the application
@@ -147,7 +161,7 @@ impl<T> EventLoopBuilderExtAndroid for EventLoopBuilder<T> {
 /// depending on the `android_activity` crate, and instead consume the API that
 /// is re-exported by Winit.
 ///
-/// For compatibility applications should then import the `AndroidApp` type for
+/// For compatibility applications should then import the [`AndroidApp`] type for
 /// their `android_main(app: AndroidApp)` function like:
 /// ```rust
 /// #[cfg(target_os = "android")]

src/platform/ios.rs

@@ -3,11 +3,14 @@
 //! Winit has an OS requirement of iOS 8 or higher, and is regularly tested on
 //! iOS 9.3.
 //!
+//! ## Window initialization
+//!
 //! iOS's main `UIApplicationMain` does some init work that's required by all
 //! UI-related code (see issue [#1705]). It is best to create your windows
-//! inside `Event::Resumed`.
+//! inside [`ApplicationHandler::resumed`].
 //!
 //! [#1705]: https://github.com/rust-windowing/winit/issues/1705
+//! [`ApplicationHandler::resumed`]: crate::application::ApplicationHandler::resumed
 //!
 //! ## Building app
 //!
@@ -63,6 +66,16 @@
 //! opengl will result in segfault.
 //!
 //! Also note that app may not receive the LoopExiting event if suspended; it might be SIGKILL'ed.
+//!
+//! ## Custom `UIApplicationDelegate`
+//!
+//! Winit usually handles everything related to the lifecycle events of the application. Sometimes,
+//! though, you might want to access some of the more niche stuff that [the application
+//! delegate][app-delegate] provides. This functionality is not exposed directly in Winit, since it
+//! would increase the API surface by quite a lot. Instead, Winit guarantees that it will not
+//! register an application delegate, so you can set up a custom one in a nib file instead.
+//!
+//! [app-delegate]: https://developer.apple.com/documentation/uikit/uiapplicationdelegate?language=objc
 
 use std::os::raw::c_void;
 

src/platform/macos.rs

@@ -3,16 +3,84 @@
 //! Winit has an OS requirement of macOS 10.11 or higher (same as Rust
 //! itself), and is regularly tested on macOS 10.14.
 //!
+//! ## Window initialization
+//!
 //! A lot of functionality expects the application to be ready before you
 //! start doing anything; this includes creating windows, fetching monitors,
 //! drawing, and so on, see issues [#2238], [#2051] and [#2087].
 //!
 //! If you encounter problems, you should try doing your initialization inside
-//! `Event::Resumed`.
+//! [`ApplicationHandler::resumed`].
 //!
 //! [#2238]: https://github.com/rust-windowing/winit/issues/2238
 //! [#2051]: https://github.com/rust-windowing/winit/issues/2051
 //! [#2087]: https://github.com/rust-windowing/winit/issues/2087
+//! [`ApplicationHandler::resumed`]: crate::application::ApplicationHandler::resumed
+//!
+//! ## Custom `NSApplicationDelegate`
+//!
+//! Winit usually handles everything related to the lifecycle events of the application. Sometimes,
+//! though, you might want to do more niche stuff, such as [handle when the user re-activates the
+//! application][reopen]. Such functionality is not exposed directly in Winit, since it would
+//! increase the API surface by quite a lot.
+//!
+//! [reopen]: https://developer.apple.com/documentation/appkit/nsapplicationdelegate/1428638-applicationshouldhandlereopen?language=objc
+//!
+//! Instead, Winit guarantees that it will not register an application delegate, so the solution is
+//! to register your own application delegate, as outlined in the following example (see
+//! `objc2-app-kit` for more detailed information).
+#![cfg_attr(target_os = "macos", doc = "```")]
+#![cfg_attr(not(target_os = "macos"), doc = "```ignore")]
+//! use objc2::rc::Retained;
+//! use objc2::runtime::ProtocolObject;
+//! use objc2::{declare_class, msg_send_id, mutability, ClassType, DeclaredClass};
+//! use objc2_app_kit::{NSApplication, NSApplicationDelegate};
+//! use objc2_foundation::{NSArray, NSURL, MainThreadMarker, NSObject, NSObjectProtocol};
+//! use winit::event_loop::EventLoop;
+//!
+//! declare_class!(
+//!     struct AppDelegate;
+//!
+//!     unsafe impl ClassType for AppDelegate {
+//!         type Super = NSObject;
+//!         type Mutability = mutability::MainThreadOnly;
+//!         const NAME: &'static str = "MyAppDelegate";
+//!     }
+//!
+//!     impl DeclaredClass for AppDelegate {}
+//!
+//!     unsafe impl NSObjectProtocol for AppDelegate {}
+//!
+//!     unsafe impl NSApplicationDelegate for AppDelegate {
+//!         #[method(application:openURLs:)]
+//!         fn application_openURLs(&self, application: &NSApplication, urls: &NSArray<NSURL>) {
+//!             // Note: To specifically get `application:openURLs:` to work, you _might_
+//!             // have to bundle your application. This is not done in this example.
+//!             println!("open urls: {application:?}, {urls:?}");
+//!         }
+//!     }
+//! );
+//!
+//! impl AppDelegate {
+//!     fn new(mtm: MainThreadMarker) -> Retained<Self> {
+//!         unsafe { msg_send_id![super(mtm.alloc().set_ivars(())), init] }
+//!     }
+//! }
+//!
+//! fn main() -> Result<(), Box<dyn std::error::Error>> {
+//!     let event_loop = EventLoop::new()?;
+//!
+//!     let mtm = MainThreadMarker::new().unwrap();
+//!     let delegate = AppDelegate::new(mtm);
+//!     // Important: Call `sharedApplication` after `EventLoop::new`,
+//!     // doing it before is not yet supported.
+//!     let app = NSApplication::sharedApplication(mtm);
+//!     app.setDelegate(Some(ProtocolObject::from_ref(&*delegate)));
+//!
+//!     // event_loop.run_app(&mut my_app);
+//!     Ok(())
+//! }
+//! ```
 
 use std::os::raw::c_void;
 
@@ -94,6 +162,14 @@ pub trait WindowExtMacOS {
 
     /// Getter for the [`WindowExtMacOS::set_option_as_alt`].
     fn option_as_alt(&self) -> OptionAsAlt;
+
+    /// Disable the Menu Bar and Dock in Simple or Borderless Fullscreen mode. Useful for games.
+    /// The effect is applied when [`WindowExtMacOS::set_simple_fullscreen`] or
+    /// [`Window::set_fullscreen`] is called.
+    fn set_borderless_game(&self, borderless_game: bool);
+
+    /// Getter for the [`WindowExtMacOS::set_borderless_game`].
+    fn is_borderless_game(&self) -> bool;
 }
 
 impl WindowExtMacOS for Window {
@@ -166,6 +242,16 @@ impl WindowExtMacOS for Window {
     fn option_as_alt(&self) -> OptionAsAlt {
         self.window.maybe_wait_on_main(|w| w.option_as_alt())
     }
+
+    #[inline]
+    fn set_borderless_game(&self, borderless_game: bool) {
+        self.window.maybe_wait_on_main(|w| w.set_borderless_game(borderless_game))
+    }
+
+    #[inline]
+    fn is_borderless_game(&self) -> bool {
+        self.window.maybe_wait_on_main(|w| w.is_borderless_game())
+    }
 }
 
 /// Corresponds to `NSApplicationActivationPolicy`.
@@ -216,6 +302,8 @@ pub trait WindowAttributesExtMacOS {
     ///
     /// See [`WindowExtMacOS::set_option_as_alt`] for details on what this means if set.
     fn with_option_as_alt(self, option_as_alt: OptionAsAlt) -> Self;
+    /// See [`WindowExtMacOS::set_borderless_game`] for details on what this means if set.
+    fn with_borderless_game(self, borderless_game: bool) -> Self;
 }
 
 impl WindowAttributesExtMacOS for WindowAttributes {
@@ -284,12 +372,21 @@ impl WindowAttributesExtMacOS for WindowAttributes {
         self.platform_specific.option_as_alt = option_as_alt;
         self
     }
+
+    #[inline]
+    fn with_borderless_game(mut self, borderless_game: bool) -> Self {
+        self.platform_specific.borderless_game = borderless_game;
+        self
+    }
 }
 
 pub trait EventLoopBuilderExtMacOS {
-    /// Sets the activation policy for the application.
+    /// Sets the activation policy for the application. If used, this will override
+    /// any relevant settings provided in the package manifest.
+    /// For instance, `with_activation_policy(ActivationPolicy::Regular)` will prevent
+    /// the application from running as an "agent", even if LSUIElement is set to true.
     ///
-    /// It is set to [`ActivationPolicy::Regular`] by default.
+    /// If unused, the Winit will honor the package manifest.
     ///
     /// # Example
     ///
@@ -341,7 +438,7 @@ pub trait EventLoopBuilderExtMacOS {
 impl<T> EventLoopBuilderExtMacOS for EventLoopBuilder<T> {
     #[inline]
     fn with_activation_policy(&mut self, activation_policy: ActivationPolicy) -> &mut Self {
-        self.platform_specific.activation_policy = activation_policy;
+        self.platform_specific.activation_policy = Some(activation_policy);
         self
     }
 

src/platform/pump_events.rs

@@ -1,13 +1,12 @@
 use std::time::Duration;
 
 use crate::application::ApplicationHandler;
-use crate::event_loop::EventLoop;
+use crate::event::Event;
+use crate::event_loop::{self, ActiveEventLoop, EventLoop};
 
 /// Additional methods on [`EventLoop`] for pumping events within an external event loop
 pub trait EventLoopExtPumpEvents {
     /// A type provided by the user that can be passed through [`Event::UserEvent`].
-    ///
-    /// [`Event::UserEvent`]: crate::event::Event::UserEvent
     type UserEvent: 'static;
 
     /// Pump the `EventLoop` to check for and dispatch pending events.
@@ -52,19 +51,19 @@ pub trait EventLoopExtPumpEvents {
     /// buffered and handled outside of Winit include:
     /// - `RedrawRequested` events, used to schedule rendering.
     ///
-    ///     macOS for example uses a `drawRect` callback to drive rendering
-    /// within applications and expects rendering to be finished before
-    /// the `drawRect` callback returns.
+    ///   macOS for example uses a `drawRect` callback to drive rendering
+    ///   within applications and expects rendering to be finished before
+    ///   the `drawRect` callback returns.
     ///
-    ///     For portability it's strongly recommended that applications should
-    /// keep their rendering inside the closure provided to Winit.
+    ///   For portability it's strongly recommended that applications should
+    ///   keep their rendering inside the closure provided to Winit.
     /// - Any lifecycle events, such as `Suspended` / `Resumed`.
     ///
-    ///     The handling of these events needs to be synchronized with the
-    /// operating system and it would never be appropriate to buffer a
-    /// notification that your application has been suspended or resumed and
-    /// then handled that later since there would always be a chance that
-    /// other lifecycle events occur while the event is buffered.
+    ///   The handling of these events needs to be synchronized with the
+    ///   operating system and it would never be appropriate to buffer a
+    ///   notification that your application has been suspended or resumed and
+    ///   then handled that later since there would always be a chance that
+    ///   other lifecycle events occur while the event is buffered.
     ///
     /// ## Supported Platforms
     ///
@@ -75,13 +74,13 @@ pub trait EventLoopExtPumpEvents {
     ///
     /// ## Unsupported Platforms
     ///
-    /// - **Web:**  This API is fundamentally incompatible with the event-based way in which
-    /// Web browsers work because it's not possible to have a long-running external
-    /// loop that would block the browser and there is nothing that can be
-    /// polled to ask for new new events. Events are delivered via callbacks based
-    /// on an event loop that is internal to the browser itself.
+    /// - **Web:**  This API is fundamentally incompatible with the event-based way in which Web
+    ///   browsers work because it's not possible to have a long-running external loop that would
+    ///   block the browser and there is nothing that can be polled to ask for new new events.
+    ///   Events are delivered via callbacks based on an event loop that is internal to the browser
+    ///   itself.
     /// - **iOS:** It's not possible to stop and start an `NSApplication` repeatedly on iOS so
-    /// there's no way to support the same approach to polling as on MacOS.
+    ///   there's no way to support the same approach to polling as on MacOS.
     ///
     /// ## Platform-specific
     ///
@@ -108,18 +107,30 @@ pub trait EventLoopExtPumpEvents {
         &mut self,
         timeout: Option<Duration>,
         app: &mut A,
-    ) -> PumpStatus;
+    ) -> PumpStatus {
+        #[allow(deprecated)]
+        self.pump_events(timeout, |event, event_loop| {
+            event_loop::dispatch_event_for_app(app, event_loop, event)
+        })
+    }
+
+    /// See [`pump_app_events`].
+    ///
+    /// [`pump_app_events`]: Self::pump_app_events
+    #[deprecated = "use EventLoopExtPumpEvents::pump_app_events"]
+    fn pump_events<F>(&mut self, timeout: Option<Duration>, event_handler: F) -> PumpStatus
+    where
+        F: FnMut(Event<Self::UserEvent>, &ActiveEventLoop);
 }
 
 impl<T> EventLoopExtPumpEvents for EventLoop<T> {
     type UserEvent = T;
 
-    fn pump_app_events<A: ApplicationHandler<Self::UserEvent>>(
-        &mut self,
-        timeout: Option<Duration>,
-        app: &mut A,
-    ) -> PumpStatus {
-        self.event_loop.pump_app_events(timeout, app)
+    fn pump_events<F>(&mut self, timeout: Option<Duration>, event_handler: F) -> PumpStatus
+    where
+        F: FnMut(Event<Self::UserEvent>, &ActiveEventLoop),
+    {
+        self.event_loop.pump_events(timeout, event_handler)
     }
 }
 

src/platform/run_on_demand.rs

@@ -1,6 +1,7 @@
 use crate::application::ApplicationHandler;
 use crate::error::EventLoopError;
-use crate::event_loop::{ActiveEventLoop, EventLoop};
+use crate::event::Event;
+use crate::event_loop::{self, ActiveEventLoop, EventLoop};
 
 #[cfg(doc)]
 use crate::{platform::pump_events::EventLoopExtPumpEvents, window::Window};
@@ -8,10 +9,16 @@ use crate::{platform::pump_events::EventLoopExtPumpEvents, window::Window};
 /// Additional methods on [`EventLoop`] to return control flow to the caller.
 pub trait EventLoopExtRunOnDemand {
     /// A type provided by the user that can be passed through [`Event::UserEvent`].
-    ///
-    /// [`Event::UserEvent`]: crate::event::Event::UserEvent
     type UserEvent: 'static;
 
+    /// See [`run_app_on_demand`].
+    ///
+    /// [`run_app_on_demand`]: Self::run_app_on_demand
+    #[deprecated = "use EventLoopExtRunOnDemand::run_app_on_demand"]
+    fn run_on_demand<F>(&mut self, event_handler: F) -> Result<(), EventLoopError>
+    where
+        F: FnMut(Event<Self::UserEvent>, &ActiveEventLoop);
+
     /// Run the application with the event loop on the calling thread.
     ///
     /// Unlike [`EventLoop::run_app`], this function accepts non-`'static` (i.e. non-`move`)
@@ -35,7 +42,9 @@ pub trait EventLoopExtRunOnDemand {
     /// # Caveats
     /// - This extension isn't available on all platforms, since it's not always possible to return
     ///   to the caller (specifically this is impossible on iOS and Web - though with the Web
-    ///   backend it is possible to use `EventLoopExtWebSys::spawn()`[^1] more than once instead).
+    ///   backend it is possible to use `EventLoopExtWebSys::spawn()`
+    #[cfg_attr(not(web_platform), doc = "[^1]")]
+    ///   more than once instead).
     /// - No [`Window`] state can be carried between separate runs of the event loop.
     ///
     /// You are strongly encouraged to use [`EventLoop::run_app()`] for portability, unless you
@@ -54,25 +63,30 @@ pub trait EventLoopExtRunOnDemand {
     ///   are delivered via callbacks based on an event loop that is internal to the browser itself.
     /// - **iOS:** It's not possible to stop and start an `UIApplication` repeatedly on iOS.
     #[cfg_attr(not(web_platform), doc = "[^1]: `spawn()` is only available on `wasm` platforms.")]
-    #[rustfmt::skip]
     ///
+    #[rustfmt::skip]
     /// [`exit()`]: ActiveEventLoop::exit()
     /// [`set_control_flow()`]: ActiveEventLoop::set_control_flow()
     fn run_app_on_demand<A: ApplicationHandler<Self::UserEvent>>(
         &mut self,
         app: &mut A,
-    ) -> Result<(), EventLoopError>;
+    ) -> Result<(), EventLoopError> {
+        #[allow(deprecated)]
+        self.run_on_demand(|event, event_loop| {
+            event_loop::dispatch_event_for_app(app, event_loop, event)
+        })
+    }
 }
 
 impl<T> EventLoopExtRunOnDemand for EventLoop<T> {
     type UserEvent = T;
 
-    fn run_app_on_demand<A: ApplicationHandler<Self::UserEvent>>(
-        &mut self,
-        app: &mut A,
-    ) -> Result<(), EventLoopError> {
+    fn run_on_demand<F>(&mut self, event_handler: F) -> Result<(), EventLoopError>
+    where
+        F: FnMut(Event<Self::UserEvent>, &ActiveEventLoop),
+    {
         self.event_loop.window_target().clear_exit();
-        self.event_loop.run_app_on_demand(app)
+        self.event_loop.run_on_demand(event_handler)
     }
 }
 

src/platform/startup_notify.rs

@@ -64,7 +64,7 @@ impl EventLoopExtStartupNotify for ActiveEventLoop {
             crate::platform_impl::ActiveEventLoop::X(_) => env::var(X11_VAR),
         }
         .ok()
-        .map(ActivationToken::_new)
+        .map(ActivationToken::from_raw)
     }
 }
 
@@ -94,6 +94,6 @@ pub fn reset_activation_token_env() {
 ///
 /// This could be used before running daemon processes.
 pub fn set_activation_token_env(token: ActivationToken) {
-    env::set_var(X11_VAR, &token._token);
-    env::set_var(WAYLAND_VAR, token._token);
+    env::set_var(X11_VAR, &token.token);
+    env::set_var(WAYLAND_VAR, token.token);
 }

src/platform/wayland.rs

@@ -13,6 +13,10 @@
 //! * `wayland-csd-adwaita` (default).
 //! * `wayland-csd-adwaita-crossfont`.
 //! * `wayland-csd-adwaita-notitle`.
+
+use std::ffi::c_void;
+use std::ptr::NonNull;
+
 use crate::event_loop::{ActiveEventLoop, EventLoop, EventLoopBuilder};
 use crate::monitor::MonitorHandle;
 use crate::window::{Window, WindowAttributes};
@@ -72,9 +76,25 @@ impl<T> EventLoopBuilderExtWayland for EventLoopBuilder<T> {
 }
 
 /// Additional methods on [`Window`] that are specific to Wayland.
-pub trait WindowExtWayland {}
+///
+/// [`Window`]: crate::window::Window
+pub trait WindowExtWayland {
+    /// Returns `xdg_toplevel` of the window or [`None`] if the window is X11 window.
+    fn xdg_toplevel(&self) -> Option<NonNull<c_void>>;
+}
 
-impl WindowExtWayland for Window {}
+impl WindowExtWayland for Window {
+    #[inline]
+    fn xdg_toplevel(&self) -> Option<NonNull<c_void>> {
+        #[allow(clippy::single_match)]
+        match &self.window {
+            #[cfg(x11_platform)]
+            crate::platform_impl::Window::X(_) => None,
+            #[cfg(wayland_platform)]
+            crate::platform_impl::Window::Wayland(window) => window.xdg_toplevel(),
+        }
+    }
+}
 
 /// Additional methods on [`WindowAttributes`] that are specific to Wayland.
 pub trait WindowAttributesExtWayland {

src/platform/web.rs

@@ -55,7 +55,8 @@ use web_sys::HtmlCanvasElement;
 
 use crate::application::ApplicationHandler;
 use crate::cursor::CustomCursorSource;
-use crate::event_loop::{ActiveEventLoop, EventLoop};
+use crate::event::Event;
+use crate::event_loop::{self, ActiveEventLoop, EventLoop};
 #[cfg(web_platform)]
 use crate::platform_impl::CustomCursorFuture as PlatformCustomCursorFuture;
 use crate::platform_impl::PlatformCustomCursorSource;
@@ -155,9 +156,7 @@ impl WindowAttributesExtWebSys for WindowAttributes {
 
 /// Additional methods on `EventLoop` that are specific to the web.
 pub trait EventLoopExtWebSys {
-    /// A type provided by the user that can be passed through [`Event::UserEvent`].
-    ///
-    /// [`Event::UserEvent`]: crate::event::Event::UserEvent
+    /// A type provided by the user that can be passed through `Event::UserEvent`.
     type UserEvent: 'static;
 
     /// Initializes the winit event loop.
@@ -183,13 +182,74 @@ pub trait EventLoopExtWebSys {
     )]
     /// [^1]: `run_app()` is _not_ available on WASM when the target supports `exception-handling`.
     fn spawn_app<A: ApplicationHandler<Self::UserEvent> + 'static>(self, app: A);
+
+    /// See [`spawn_app`].
+    ///
+    /// [`spawn_app`]: Self::spawn_app
+    #[deprecated = "use EventLoopExtWebSys::spawn_app"]
+    fn spawn<F>(self, event_handler: F)
+    where
+        F: 'static + FnMut(Event<Self::UserEvent>, &ActiveEventLoop);
+
+    /// Sets the strategy for [`ControlFlow::Poll`].
+    ///
+    /// See [`PollStrategy`].
+    ///
+    /// [`ControlFlow::Poll`]: crate::event_loop::ControlFlow::Poll
+    fn set_poll_strategy(&self, strategy: PollStrategy);
+
+    /// Gets the strategy for [`ControlFlow::Poll`].
+    ///
+    /// See [`PollStrategy`].
+    ///
+    /// [`ControlFlow::Poll`]: crate::event_loop::ControlFlow::Poll
+    fn poll_strategy(&self) -> PollStrategy;
+
+    /// Sets the strategy for [`ControlFlow::WaitUntil`].
+    ///
+    /// See [`WaitUntilStrategy`].
+    ///
+    /// [`ControlFlow::WaitUntil`]: crate::event_loop::ControlFlow::WaitUntil
+    fn set_wait_until_strategy(&self, strategy: WaitUntilStrategy);
+
+    /// Gets the strategy for [`ControlFlow::WaitUntil`].
+    ///
+    /// See [`WaitUntilStrategy`].
+    ///
+    /// [`ControlFlow::WaitUntil`]: crate::event_loop::ControlFlow::WaitUntil
+    fn wait_until_strategy(&self) -> WaitUntilStrategy;
 }
 
 impl<T> EventLoopExtWebSys for EventLoop<T> {
     type UserEvent = T;
 
-    fn spawn_app<A: ApplicationHandler<Self::UserEvent> + 'static>(self, app: A) {
-        self.event_loop.spawn_app(app);
+    fn spawn_app<A: ApplicationHandler<Self::UserEvent> + 'static>(self, mut app: A) {
+        self.event_loop.spawn(move |event, event_loop| {
+            event_loop::dispatch_event_for_app(&mut app, event_loop, event)
+        });
+    }
+
+    fn spawn<F>(self, event_handler: F)
+    where
+        F: 'static + FnMut(Event<Self::UserEvent>, &ActiveEventLoop),
+    {
+        self.event_loop.spawn(event_handler)
+    }
+
+    fn set_poll_strategy(&self, strategy: PollStrategy) {
+        self.event_loop.set_poll_strategy(strategy);
+    }
+
+    fn poll_strategy(&self) -> PollStrategy {
+        self.event_loop.poll_strategy()
+    }
+
+    fn set_wait_until_strategy(&self, strategy: WaitUntilStrategy) {
+        self.event_loop.set_wait_until_strategy(strategy);
+    }
+
+    fn wait_until_strategy(&self) -> WaitUntilStrategy {
+        self.event_loop.wait_until_strategy()
     }
 }
 
@@ -208,6 +268,20 @@ pub trait ActiveEventLoopExtWebSys {
     /// [`ControlFlow::Poll`]: crate::event_loop::ControlFlow::Poll
     fn poll_strategy(&self) -> PollStrategy;
 
+    /// Sets the strategy for [`ControlFlow::WaitUntil`].
+    ///
+    /// See [`WaitUntilStrategy`].
+    ///
+    /// [`ControlFlow::WaitUntil`]: crate::event_loop::ControlFlow::WaitUntil
+    fn set_wait_until_strategy(&self, strategy: WaitUntilStrategy);
+
+    /// Gets the strategy for [`ControlFlow::WaitUntil`].
+    ///
+    /// See [`WaitUntilStrategy`].
+    ///
+    /// [`ControlFlow::WaitUntil`]: crate::event_loop::ControlFlow::WaitUntil
+    fn wait_until_strategy(&self) -> WaitUntilStrategy;
+
     /// Async version of [`ActiveEventLoop::create_custom_cursor()`] which waits until the
     /// cursor has completely finished loading.
     fn create_custom_cursor_async(&self, source: CustomCursorSource) -> CustomCursorFuture;
@@ -228,6 +302,16 @@ impl ActiveEventLoopExtWebSys for ActiveEventLoop {
     fn poll_strategy(&self) -> PollStrategy {
         self.p.poll_strategy()
     }
+
+    #[inline]
+    fn set_wait_until_strategy(&self, strategy: WaitUntilStrategy) {
+        self.p.set_wait_until_strategy(strategy);
+    }
+
+    #[inline]
+    fn wait_until_strategy(&self) -> WaitUntilStrategy {
+        self.p.wait_until_strategy()
+    }
 }
 
 /// Strategy used for [`ControlFlow::Poll`][crate::event_loop::ControlFlow::Poll].
@@ -256,6 +340,29 @@ pub enum PollStrategy {
     Scheduler,
 }
 
+/// Strategy used for [`ControlFlow::WaitUntil`][crate::event_loop::ControlFlow::WaitUntil].
+#[derive(Clone, Copy, Debug, Default, PartialEq, Eq)]
+pub enum WaitUntilStrategy {
+    /// Uses the [Prioritized Task Scheduling API] to queue the next event loop. If not available
+    /// this will fallback to [`setTimeout()`].
+    ///
+    /// This strategy is commonly not affected by browser throttling unless the window is not
+    /// focused.
+    ///
+    /// This is the default strategy.
+    ///
+    /// [Prioritized Task Scheduling API]: https://developer.mozilla.org/en-US/docs/Web/API/Prioritized_Task_Scheduling_API
+    /// [`setTimeout()`]: https://developer.mozilla.org/en-US/docs/Web/API/setTimeout
+    #[default]
+    Scheduler,
+    /// Equal to [`Scheduler`][Self::Scheduler] but wakes up the event loop from a [worker].
+    ///
+    /// This strategy is commonly not affected by browser throttling regardless of window focus.
+    ///
+    /// [worker]: https://developer.mozilla.org/en-US/docs/Web/API/Web_Workers_API
+    Worker,
+}
+
 pub trait CustomCursorExtWebSys {
     /// Returns if this cursor is an animation.
     fn is_animation(&self) -> bool;
@@ -315,7 +422,7 @@ impl fmt::Display for BadAnimation {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self {
             Self::Empty => write!(f, "No cursors supplied"),
-            Self::Animation => write!(f, "A supplied cursor is an animtion"),
+            Self::Animation => write!(f, "A supplied cursor is an animation"),
         }
     }
 }
@@ -354,3 +461,5 @@ impl Display for CustomCursorError {
         }
     }
 }
+
+impl Error for CustomCursorError {}

src/platform/windows.rs

@@ -660,6 +660,17 @@ impl DeviceIdExtWindows for DeviceId {
 }
 
 /// Additional methods on `Icon` that are specific to Windows.
+///
+/// Windows icons can be created from files, or from the [`embedded resources`](https://learn.microsoft.com/en-us/windows/win32/menurc/about-resource-files).
+///
+/// The `ICON` resource definition statement use the following syntax:
+/// ```rc
+/// nameID ICON filename
+/// ```
+/// `nameID` is a unique name or a 16-bit unsigned integer value identifying the resource,
+/// `filename` is the name of the file that contains the resource.
+///
+/// More information about the `ICON` resource can be found at [`Microsoft Learn`](https://learn.microsoft.com/en-us/windows/win32/menurc/icon-resource) portal.
 pub trait IconExtWindows: Sized {
     /// Create an icon from a file path.
     ///
@@ -671,7 +682,12 @@ pub trait IconExtWindows: Sized {
     fn from_path<P: AsRef<Path>>(path: P, size: Option<PhysicalSize<u32>>)
         -> Result<Self, BadIcon>;
 
-    /// Create an icon from a resource embedded in this executable or library.
+    /// Create an icon from a resource embedded in this executable or library by its ordinal id.
+    ///
+    /// The valid `ordinal` values range from 1 to [`u16::MAX`] (inclusive). The value `0` is an
+    /// invalid ordinal id, but it can be used with [`from_resource_name`] as `"0"`.
+    ///
+    /// [`from_resource_name`]: IconExtWindows::from_resource_name
     ///
     /// Specify `size` to load a specific icon size from the file, or `None` to load the default
     /// icon size from the file.
@@ -679,6 +695,55 @@ pub trait IconExtWindows: Sized {
     /// In cases where the specified size does not exist in the file, Windows may perform scaling
     /// to get an icon of the desired size.
     fn from_resource(ordinal: u16, size: Option<PhysicalSize<u32>>) -> Result<Self, BadIcon>;
+
+    /// Create an icon from a resource embedded in this executable or library by its name.
+    ///
+    /// Specify `size` to load a specific icon size from the file, or `None` to load the default
+    /// icon size from the file.
+    ///
+    /// In cases where the specified size does not exist in the file, Windows may perform scaling
+    /// to get an icon of the desired size.
+    ///
+    /// # Notes
+    ///
+    /// Consider the following resource definition statements:
+    /// ```rc
+    /// app     ICON "app.ico"
+    /// 1       ICON "a.ico"
+    /// 0027    ICON "custom.ico"
+    /// 0       ICON "alt.ico"
+    /// ```
+    ///
+    /// Due to some internal implementation details of the resource embedding/loading process on
+    /// Windows platform, strings that can be interpreted as 16-bit unsigned integers (`"1"`,
+    /// `"002"`, etc.) cannot be used as valid resource names, and instead should be passed into
+    /// [`from_resource`]:
+    ///
+    /// [`from_resource`]: IconExtWindows::from_resource
+    ///
+    /// ```rust,no_run
+    /// use winit::platform::windows::IconExtWindows;
+    /// use winit::window::Icon;
+    ///
+    /// assert!(Icon::from_resource_name("app", None).is_ok());
+    /// assert!(Icon::from_resource(1, None).is_ok());
+    /// assert!(Icon::from_resource(27, None).is_ok());
+    /// assert!(Icon::from_resource_name("27", None).is_err());
+    /// assert!(Icon::from_resource_name("0027", None).is_err());
+    /// ```
+    ///
+    /// While `0` cannot be used as an ordinal id (see [`from_resource`]), it can be used as a
+    /// name:
+    ///
+    /// [`from_resource`]: IconExtWindows::from_resource
+    ///
+    /// ```rust,no_run
+    /// # use winit::platform::windows::IconExtWindows;
+    /// # use winit::window::Icon;
+    /// assert!(Icon::from_resource_name("0", None).is_ok());
+    /// assert!(Icon::from_resource(0, None).is_err());
+    /// ```
+    fn from_resource_name(name: &str, size: Option<PhysicalSize<u32>>) -> Result<Self, BadIcon>;
 }
 
 impl IconExtWindows for Icon {
@@ -694,4 +759,9 @@ impl IconExtWindows for Icon {
         let win_icon = crate::platform_impl::WinIcon::from_resource(ordinal, size)?;
         Ok(Icon { inner: win_icon })
     }
+
+    fn from_resource_name(name: &str, size: Option<PhysicalSize<u32>>) -> Result<Self, BadIcon> {
+        let win_icon = crate::platform_impl::WinIcon::from_resource_name(name, size)?;
+        Ok(Icon { inner: win_icon })
+    }
 }

src/platform/x11.rs

@@ -81,9 +81,7 @@ pub type XWindow = u32;
 #[inline]
 pub fn register_xlib_error_hook(hook: XlibErrorHook) {
     // Append new hook.
-    unsafe {
-        crate::platform_impl::XLIB_ERROR_HOOKS.lock().unwrap().push(hook);
-    }
+    crate::platform_impl::XLIB_ERROR_HOOKS.lock().unwrap().push(hook);
 }
 
 /// Additional methods on [`ActiveEventLoop`] that are specific to X11.

src/platform_impl/android/mod.rs

@@ -1,5 +1,3 @@
-#![cfg(android_platform)]
-
 use std::cell::Cell;
 use std::collections::VecDeque;
 use std::hash::Hash;
@@ -14,13 +12,12 @@ use android_activity::{
 };
 use tracing::{debug, trace, warn};
 
-use crate::application::ApplicationHandler;
 use crate::cursor::Cursor;
 use crate::dpi::{PhysicalPosition, PhysicalSize, Position, Size};
 use crate::error;
 use crate::error::EventLoopError;
 use crate::event::{self, Force, InnerSizeWriter, StartCause};
-use crate::event_loop::{self, ControlFlow, DeviceEvents};
+use crate::event_loop::{self, ActiveEventLoop as RootAEL, ControlFlow, DeviceEvents};
 use crate::platform::pump_events::PumpStatus;
 use crate::platform_impl::Fullscreen;
 use crate::window::{
@@ -135,7 +132,7 @@ impl RedrawRequester {
 pub struct KeyEventExtra {}
 
 pub struct EventLoop<T: 'static> {
-    android_app: AndroidApp,
+    pub(crate) android_app: AndroidApp,
     window_target: event_loop::ActiveEventLoop,
     redraw_flag: SharedFlag,
     user_events_sender: mpsc::Sender<T>,
@@ -198,28 +195,27 @@ impl<T: 'static> EventLoop<T> {
         })
     }
 
-    fn single_iteration<A: ApplicationHandler<T>>(
-        &mut self,
-        main_event: Option<MainEvent<'_>>,
-        app: &mut A,
-    ) {
+    fn single_iteration<F>(&mut self, main_event: Option<MainEvent<'_>>, callback: &mut F)
+    where
+        F: FnMut(event::Event<T>, &RootAEL),
+    {
         trace!("Mainloop iteration");
 
         let cause = self.cause;
         let mut pending_redraw = self.pending_redraw;
         let mut resized = false;
 
-        app.new_events(self.window_target(), cause);
+        callback(event::Event::NewEvents(cause), self.window_target());
 
         if let Some(event) = main_event {
             trace!("Handling main event {:?}", event);
 
             match event {
                 MainEvent::InitWindow { .. } => {
-                    app.resumed(self.window_target());
+                    callback(event::Event::Resumed, self.window_target());
                 },
                 MainEvent::TerminateWindow { .. } => {
-                    app.suspended(self.window_target());
+                    callback(event::Event::Suspended, self.window_target());
                 },
                 MainEvent::WindowResized { .. } => resized = true,
                 MainEvent::RedrawNeeded { .. } => pending_redraw = true,
@@ -228,15 +224,23 @@ impl<T: 'static> EventLoop<T> {
                 },
                 MainEvent::GainedFocus => {
                     HAS_FOCUS.store(true, Ordering::Relaxed);
-                    let window_id = window::WindowId(WindowId);
-                    let event = event::WindowEvent::Focused(true);
-                    app.window_event(self.window_target(), window_id, event);
+                    callback(
+                        event::Event::WindowEvent {
+                            window_id: window::WindowId(WindowId),
+                            event: event::WindowEvent::Focused(true),
+                        },
+                        self.window_target(),
+                    );
                 },
                 MainEvent::LostFocus => {
                     HAS_FOCUS.store(false, Ordering::Relaxed);
-                    let window_id = window::WindowId(WindowId);
-                    let event = event::WindowEvent::Focused(false);
-                    app.window_event(self.window_target(), window_id, event);
+                    callback(
+                        event::Event::WindowEvent {
+                            window_id: window::WindowId(WindowId),
+                            event: event::WindowEvent::Focused(false),
+                        },
+                        self.window_target(),
+                    );
                 },
                 MainEvent::ConfigChanged { .. } => {
                     let monitor = MonitorHandle::new(self.android_app.clone());
@@ -246,19 +250,20 @@ impl<T: 'static> EventLoop<T> {
                         let new_inner_size = Arc::new(Mutex::new(
                             MonitorHandle::new(self.android_app.clone()).size(),
                         ));
-                        let window_id = window::WindowId(WindowId);
-                        let event = event::WindowEvent::ScaleFactorChanged {
-                            inner_size_writer: InnerSizeWriter::new(Arc::downgrade(
-                                &new_inner_size,
-                            )),
-                            scale_factor,
+                        let event = event::Event::WindowEvent {
+                            window_id: window::WindowId(WindowId),
+                            event: event::WindowEvent::ScaleFactorChanged {
+                                inner_size_writer: InnerSizeWriter::new(Arc::downgrade(
+                                    &new_inner_size,
+                                )),
+                                scale_factor,
+                            },
                         };
-
-                        app.window_event(self.window_target(), window_id, event);
+                        callback(event, self.window_target());
                     }
                 },
                 MainEvent::LowMemory => {
-                    app.memory_warning(self.window_target());
+                    callback(event::Event::MemoryWarning, self.window_target());
                 },
                 MainEvent::Start => {
                     // XXX: how to forward this state to applications?
@@ -306,7 +311,7 @@ impl<T: 'static> EventLoop<T> {
         match android_app.input_events_iter() {
             Ok(mut input_iter) => loop {
                 let read_event =
-                    input_iter.next(|event| self.handle_input_event(&android_app, event, app));
+                    input_iter.next(|event| self.handle_input_event(&android_app, event, callback));
 
                 if !read_event {
                     break;
@@ -320,7 +325,7 @@ impl<T: 'static> EventLoop<T> {
         // Empty the user event buffer
         {
             while let Ok(event) = self.user_events_receiver.try_recv() {
-                app.user_event(self.window_target(), event);
+                callback(crate::event::Event::UserEvent(event), self.window_target());
             }
         }
 
@@ -333,32 +338,39 @@ impl<T: 'static> EventLoop<T> {
                 } else {
                     PhysicalSize::new(0, 0)
                 };
-                let window_id = window::WindowId(WindowId);
-                let event = event::WindowEvent::Resized(size);
-                app.window_event(self.window_target(), window_id, event);
+                let event = event::Event::WindowEvent {
+                    window_id: window::WindowId(WindowId),
+                    event: event::WindowEvent::Resized(size),
+                };
+                callback(event, self.window_target());
             }
 
             pending_redraw |= self.redraw_flag.get_and_reset();
             if pending_redraw {
                 pending_redraw = false;
-                let window_id = window::WindowId(WindowId);
-                let event = event::WindowEvent::RedrawRequested;
-                app.window_event(self.window_target(), window_id, event);
+                let event = event::Event::WindowEvent {
+                    window_id: window::WindowId(WindowId),
+                    event: event::WindowEvent::RedrawRequested,
+                };
+                callback(event, self.window_target());
             }
         }
 
         // This is always the last event we dispatch before poll again
-        app.about_to_wait(self.window_target());
+        callback(event::Event::AboutToWait, self.window_target());
 
         self.pending_redraw = pending_redraw;
     }
 
-    fn handle_input_event<A: ApplicationHandler<T>>(
+    fn handle_input_event<F>(
         &mut self,
         android_app: &AndroidApp,
         event: &InputEvent<'_>,
-        app: &mut A,
-    ) -> InputStatus {
+        callback: &mut F,
+    ) -> InputStatus
+    where
+        F: FnMut(event::Event<T>, &RootAEL),
+    {
         let mut input_status = InputStatus::Handled;
         match event {
             InputEvent::MotionEvent(motion_event) => {
@@ -396,16 +408,17 @@ impl<T: 'static> EventLoop<T> {
                             "Input event {device_id:?}, {phase:?}, loc={location:?}, \
                              pointer={pointer:?}"
                         );
-
-                        let event = event::WindowEvent::Touch(event::Touch {
-                            device_id,
-                            phase,
-                            location,
-                            id: pointer.pointer_id() as u64,
-                            force: Some(Force::Normalized(pointer.pressure() as f64)),
-                        });
-
-                        app.window_event(self.window_target(), window_id, event);
+                        let event = event::Event::WindowEvent {
+                            window_id,
+                            event: event::WindowEvent::Touch(event::Touch {
+                                device_id,
+                                phase,
+                                location,
+                                id: pointer.pointer_id() as u64,
+                                force: Some(Force::Normalized(pointer.pressure() as f64)),
+                            }),
+                        };
+                        callback(event, self.window_target());
                     }
                 }
             },
@@ -433,22 +446,23 @@ impl<T: 'static> EventLoop<T> {
                             &mut self.combining_accent,
                         );
 
-                        let window_id = window::WindowId(WindowId);
-                        let event = event::WindowEvent::KeyboardInput {
-                            device_id: event::DeviceId(DeviceId(key.device_id())),
-                            event: event::KeyEvent {
-                                state,
-                                physical_key: keycodes::to_physical_key(keycode),
-                                logical_key: keycodes::to_logical(key_char, keycode),
-                                location: keycodes::to_location(keycode),
-                                repeat: key.repeat_count() > 0,
-                                text: None,
-                                platform_specific: KeyEventExtra {},
+                        let event = event::Event::WindowEvent {
+                            window_id: window::WindowId(WindowId),
+                            event: event::WindowEvent::KeyboardInput {
+                                device_id: event::DeviceId(DeviceId(key.device_id())),
+                                event: event::KeyEvent {
+                                    state,
+                                    physical_key: keycodes::to_physical_key(keycode),
+                                    logical_key: keycodes::to_logical(key_char, keycode),
+                                    location: keycodes::to_location(keycode),
+                                    repeat: key.repeat_count() > 0,
+                                    text: None,
+                                    platform_specific: KeyEventExtra {},
+                                },
+                                is_synthetic: false,
                             },
-                            is_synthetic: false,
                         };
-
-                        app.window_event(self.window_target(), window_id, event);
+                        callback(event, self.window_target());
                     },
                 }
             },
@@ -460,16 +474,19 @@ impl<T: 'static> EventLoop<T> {
         input_status
     }
 
-    pub fn run_app<A: ApplicationHandler<T>>(mut self, app: &mut A) -> Result<(), EventLoopError> {
-        self.run_app_on_demand(app)
+    pub fn run<F>(mut self, event_handler: F) -> Result<(), EventLoopError>
+    where
+        F: FnMut(event::Event<T>, &event_loop::ActiveEventLoop),
+    {
+        self.run_on_demand(event_handler)
     }
 
-    pub fn run_app_on_demand<A: ApplicationHandler<T>>(
-        &mut self,
-        app: &mut A,
-    ) -> Result<(), EventLoopError> {
+    pub fn run_on_demand<F>(&mut self, mut event_handler: F) -> Result<(), EventLoopError>
+    where
+        F: FnMut(event::Event<T>, &event_loop::ActiveEventLoop),
+    {
         loop {
-            match self.pump_app_events(None, app) {
+            match self.pump_events(None, &mut event_handler) {
                 PumpStatus::Exit(0) => {
                     break Ok(());
                 },
@@ -483,11 +500,10 @@ impl<T: 'static> EventLoop<T> {
         }
     }
 
-    pub fn pump_app_events<A: ApplicationHandler<T>>(
-        &mut self,
-        timeout: Option<Duration>,
-        app: &mut A,
-    ) -> PumpStatus {
+    pub fn pump_events<F>(&mut self, timeout: Option<Duration>, mut callback: F) -> PumpStatus
+    where
+        F: FnMut(event::Event<T>, &RootAEL),
+    {
         if !self.loop_running {
             self.loop_running = true;
 
@@ -498,18 +514,18 @@ impl<T: 'static> EventLoop<T> {
             self.cause = StartCause::Init;
 
             // run the initial loop iteration
-            self.single_iteration(None, app);
+            self.single_iteration(None, &mut callback);
         }
 
         // Consider the possibility that the `StartCause::Init` iteration could
         // request to Exit
         if !self.exiting() {
-            self.poll_events_with_timeout(timeout, app);
+            self.poll_events_with_timeout(timeout, &mut callback);
         }
         if self.exiting() {
             self.loop_running = false;
 
-            app.exiting(self.window_target());
+            callback(event::Event::LoopExiting, self.window_target());
 
             PumpStatus::Exit(0)
         } else {
@@ -517,11 +533,10 @@ impl<T: 'static> EventLoop<T> {
         }
     }
 
-    fn poll_events_with_timeout<A: ApplicationHandler<T>>(
-        &mut self,
-        mut timeout: Option<Duration>,
-        app: &mut A,
-    ) {
+    fn poll_events_with_timeout<F>(&mut self, mut timeout: Option<Duration>, mut callback: F)
+    where
+        F: FnMut(event::Event<T>, &RootAEL),
+    {
         let start = Instant::now();
 
         self.pending_redraw |= self.redraw_flag.get_and_reset();
@@ -542,8 +557,8 @@ impl<T: 'static> EventLoop<T> {
                 min_timeout(control_flow_timeout, timeout)
             };
 
-        let android_app = self.android_app.clone(); // Don't borrow self as part of poll expression
-        android_app.poll_events(timeout, |poll_event| {
+        let app = self.android_app.clone(); // Don't borrow self as part of poll expression
+        app.poll_events(timeout, |poll_event| {
             let mut main_event = None;
 
             match poll_event {
@@ -584,7 +599,7 @@ impl<T: 'static> EventLoop<T> {
                 },
             };
 
-            self.single_iteration(main_event, app);
+            self.single_iteration(main_event, &mut callback);
         });
     }
 
@@ -631,7 +646,7 @@ impl<T> EventLoopProxy<T> {
 }
 
 pub struct ActiveEventLoop {
-    app: AndroidApp,
+    pub(crate) app: AndroidApp,
     control_flow: Cell<ControlFlow>,
     exit: Cell<bool>,
     redraw_requester: RedrawRequester,
@@ -662,6 +677,11 @@ impl ActiveEventLoop {
         rwh_05::RawDisplayHandle::Android(rwh_05::AndroidDisplayHandle::empty())
     }
 
+    #[inline]
+    pub fn system_theme(&self) -> Option<Theme> {
+        None
+    }
+
     #[cfg(feature = "rwh_06")]
     #[inline]
     pub fn raw_display_handle_rwh_06(
@@ -888,7 +908,13 @@ impl Window {
 
     pub fn set_ime_cursor_area(&self, _position: Position, _size: Size) {}
 
-    pub fn set_ime_allowed(&self, _allowed: bool) {}
+    pub fn set_ime_allowed(&self, allowed: bool) {
+        if allowed {
+            self.app.show_soft_input(true);
+        } else {
+            self.app.hide_soft_input(true);
+        }
+    }
 
     pub fn set_ime_purpose(&self, _purpose: ImePurpose) {}
 

src/platform_impl/ios/app_delegate.rs

@@ -1,103 +0,0 @@
-use objc2::{declare_class, mutability, ClassType, DeclaredClass};
-use objc2_foundation::{MainThreadMarker, NSObject, NSObjectProtocol};
-use objc2_ui_kit::{UIApplication, UIWindow};
-
-use super::app_state::{self, EventWrapper};
-use super::window::WinitUIWindow;
-use crate::event::{Event, WindowEvent};
-use crate::window::WindowId as RootWindowId;
-
-declare_class!(
-    pub struct AppDelegate;
-
-    unsafe impl ClassType for AppDelegate {
-        type Super = NSObject;
-        type Mutability = mutability::InteriorMutable;
-        const NAME: &'static str = "WinitApplicationDelegate";
-    }
-
-    impl DeclaredClass for AppDelegate {}
-
-    // UIApplicationDelegate protocol
-    unsafe impl AppDelegate {
-        #[method(application:didFinishLaunchingWithOptions:)]
-        fn did_finish_launching(&self, _application: &UIApplication, _: *mut NSObject) -> bool {
-            app_state::did_finish_launching(MainThreadMarker::new().unwrap());
-            true
-        }
-
-        #[method(applicationDidBecomeActive:)]
-        fn did_become_active(&self, _application: &UIApplication) {
-            let mtm = MainThreadMarker::new().unwrap();
-            app_state::handle_nonuser_event(mtm, EventWrapper::StaticEvent(Event::Resumed))
-        }
-
-        #[method(applicationWillResignActive:)]
-        fn will_resign_active(&self, _application: &UIApplication) {
-            let mtm = MainThreadMarker::new().unwrap();
-            app_state::handle_nonuser_event(mtm, EventWrapper::StaticEvent(Event::Suspended))
-        }
-
-        #[method(applicationWillEnterForeground:)]
-        fn will_enter_foreground(&self, application: &UIApplication) {
-            self.send_occluded_event_for_all_windows(application, false);
-        }
-
-        #[method(applicationDidEnterBackground:)]
-        fn did_enter_background(&self, application: &UIApplication) {
-            self.send_occluded_event_for_all_windows(application, true);
-        }
-
-        #[method(applicationWillTerminate:)]
-        fn will_terminate(&self, application: &UIApplication) {
-            let mut events = Vec::new();
-            #[allow(deprecated)]
-            for window in application.windows().iter() {
-                if window.is_kind_of::<WinitUIWindow>() {
-                    // SAFETY: We just checked that the window is a `winit` window
-                    let window = unsafe {
-                        let ptr: *const UIWindow = window;
-                        let ptr: *const WinitUIWindow = ptr.cast();
-                        &*ptr
-                    };
-                    events.push(EventWrapper::StaticEvent(Event::WindowEvent {
-                        window_id: RootWindowId(window.id()),
-                        event: WindowEvent::Destroyed,
-                    }));
-                }
-            }
-            let mtm = MainThreadMarker::new().unwrap();
-            app_state::handle_nonuser_events(mtm, events);
-            app_state::terminated(mtm);
-        }
-
-        #[method(applicationDidReceiveMemoryWarning:)]
-        fn did_receive_memory_warning(&self, _application: &UIApplication) {
-            let mtm = MainThreadMarker::new().unwrap();
-            app_state::handle_nonuser_event(mtm, EventWrapper::StaticEvent(Event::MemoryWarning))
-        }
-    }
-);
-
-impl AppDelegate {
-    fn send_occluded_event_for_all_windows(&self, application: &UIApplication, occluded: bool) {
-        let mut events = Vec::new();
-        #[allow(deprecated)]
-        for window in application.windows().iter() {
-            if window.is_kind_of::<WinitUIWindow>() {
-                // SAFETY: We just checked that the window is a `winit` window
-                let window = unsafe {
-                    let ptr: *const UIWindow = window;
-                    let ptr: *const WinitUIWindow = ptr.cast();
-                    &*ptr
-                };
-                events.push(EventWrapper::StaticEvent(Event::WindowEvent {
-                    window_id: RootWindowId(window.id()),
-                    event: WindowEvent::Occluded(occluded),
-                }));
-            }
-        }
-        let mtm = MainThreadMarker::new().unwrap();
-        app_state::handle_nonuser_events(mtm, events);
-    }
-}

src/platform_impl/ios/app_state.rs

@@ -20,7 +20,7 @@ use objc2_foundation::{
     CGRect, CGSize, MainThreadMarker, NSInteger, NSObjectProtocol, NSOperatingSystemVersion,
     NSProcessInfo,
 };
-use objc2_ui_kit::{UICoordinateSpace, UIView};
+use objc2_ui_kit::{UIApplication, UICoordinateSpace, UIView, UIWindow};
 
 use super::window::WinitUIWindow;
 use crate::dpi::PhysicalSize;
@@ -147,6 +147,8 @@ impl AppState {
         // must be mut because plain `static` requires `Sync`
         static mut APP_STATE: RefCell<Option<AppState>> = RefCell::new(None);
 
+        #[allow(unknown_lints)] // New lint below
+        #[allow(static_mut_refs)] // TODO: Use `MainThreadBound` instead.
         let mut guard = unsafe { APP_STATE.borrow_mut() };
         if guard.is_none() {
             #[inline(never)]
@@ -373,6 +375,7 @@ impl AppState {
             (ControlFlow::Wait, ControlFlow::Wait) => {
                 let start = Instant::now();
                 self.set_state(AppStateImpl::Waiting { waiting_handler, start });
+                self.waker.stop()
             },
             (ControlFlow::WaitUntil(old_instant), ControlFlow::WaitUntil(new_instant))
                 if old_instant == new_instant =>
@@ -662,6 +665,28 @@ fn handle_user_events(mtm: MainThreadMarker) {
     }
 }
 
+pub(crate) fn send_occluded_event_for_all_windows(application: &UIApplication, occluded: bool) {
+    let mtm = MainThreadMarker::from(application);
+
+    let mut events = Vec::new();
+    #[allow(deprecated)]
+    for window in application.windows().iter() {
+        if window.is_kind_of::<WinitUIWindow>() {
+            // SAFETY: We just checked that the window is a `winit` window
+            let window = unsafe {
+                let ptr: *const UIWindow = window;
+                let ptr: *const WinitUIWindow = ptr.cast();
+                &*ptr
+            };
+            events.push(EventWrapper::StaticEvent(Event::WindowEvent {
+                window_id: RootWindowId(window.id()),
+                event: WindowEvent::Occluded(occluded),
+            }));
+        }
+    }
+    handle_nonuser_events(mtm, events);
+}
+
 pub fn handle_main_events_cleared(mtm: MainThreadMarker) {
     let mut this = AppState::get_mut(mtm);
     if !this.has_launched() || this.has_terminated() {
@@ -696,7 +721,27 @@ pub fn handle_events_cleared(mtm: MainThreadMarker) {
     AppState::get_mut(mtm).events_cleared_transition();
 }
 
-pub fn terminated(mtm: MainThreadMarker) {
+pub(crate) fn terminated(application: &UIApplication) {
+    let mtm = MainThreadMarker::from(application);
+
+    let mut events = Vec::new();
+    #[allow(deprecated)]
+    for window in application.windows().iter() {
+        if window.is_kind_of::<WinitUIWindow>() {
+            // SAFETY: We just checked that the window is a `winit` window
+            let window = unsafe {
+                let ptr: *const UIWindow = window;
+                let ptr: *const WinitUIWindow = ptr.cast();
+                &*ptr
+            };
+            events.push(EventWrapper::StaticEvent(Event::WindowEvent {
+                window_id: RootWindowId(window.id()),
+                event: WindowEvent::Destroyed,
+            }));
+        }
+    }
+    handle_nonuser_events(mtm, events);
+
     let mut this = AppState::get_mut(mtm);
     let mut handler = this.terminated_transition();
     drop(this);
@@ -756,7 +801,7 @@ impl EventLoopWaker {
             // future, but that gets changed to fire immediately in did_finish_launching
             let timer = CFRunLoopTimerCreate(
                 ptr::null_mut(),
-                std::f64::MAX,
+                f64::MAX,
                 0.000_000_1,
                 0,
                 0,
@@ -770,11 +815,11 @@ impl EventLoopWaker {
     }
 
     fn stop(&mut self) {
-        unsafe { CFRunLoopTimerSetNextFireDate(self.timer, std::f64::MAX) }
+        unsafe { CFRunLoopTimerSetNextFireDate(self.timer, f64::MAX) }
     }
 
     fn start(&mut self) {
-        unsafe { CFRunLoopTimerSetNextFireDate(self.timer, std::f64::MIN) }
+        unsafe { CFRunLoopTimerSetNextFireDate(self.timer, f64::MIN) }
     }
 
     fn start_at(&mut self, instant: Instant) {

src/platform_impl/ios/event_loop.rs

@@ -13,21 +13,26 @@ use core_foundation::runloop::{
 };
 use objc2::rc::Retained;
 use objc2::{msg_send_id, ClassType};
-use objc2_foundation::{MainThreadMarker, NSString};
-use objc2_ui_kit::{UIApplication, UIApplicationMain, UIDevice, UIScreen, UIUserInterfaceIdiom};
+use objc2_foundation::{MainThreadMarker, NSNotificationCenter, NSObject};
+use objc2_ui_kit::{
+    UIApplication, UIApplicationDidBecomeActiveNotification,
+    UIApplicationDidEnterBackgroundNotification, UIApplicationDidFinishLaunchingNotification,
+    UIApplicationDidReceiveMemoryWarningNotification, UIApplicationMain,
+    UIApplicationWillEnterForegroundNotification, UIApplicationWillResignActiveNotification,
+    UIApplicationWillTerminateNotification, UIDevice, UIScreen, UIUserInterfaceIdiom,
+};
 
-use crate::application::ApplicationHandler;
 use crate::error::EventLoopError;
 use crate::event::Event;
 use crate::event_loop::{
     ActiveEventLoop as RootActiveEventLoop, ControlFlow, DeviceEvents, EventLoopClosed,
 };
 use crate::platform::ios::Idiom;
-use crate::platform_impl::platform::app_state::{EventLoopHandler, HandlePendingUserEvents};
-use crate::window::{CustomCursor, CustomCursorSource};
+use crate::platform_impl::ios::app_state::{EventLoopHandler, HandlePendingUserEvents};
+use crate::window::{CustomCursor, CustomCursorSource, Theme};
 
-use super::app_delegate::AppDelegate;
-use super::app_state::AppState;
+use super::app_state::{send_occluded_event_for_all_windows, AppState, EventWrapper};
+use super::notification_center::create_observer;
 use super::{app_state, monitor, MonitorHandle};
 
 #[derive(Debug)]
@@ -59,6 +64,11 @@ impl ActiveEventLoop {
         rwh_05::RawDisplayHandle::UiKit(rwh_05::UiKitDisplayHandle::empty())
     }
 
+    #[inline]
+    pub fn system_theme(&self) -> Option<Theme> {
+        None
+    }
+
     #[cfg(feature = "rwh_06")]
     #[inline]
     pub fn raw_display_handle_rwh_06(
@@ -109,28 +119,17 @@ impl OwnedDisplayHandle {
     }
 }
 
-fn map_user_event<T: 'static, A: ApplicationHandler<T>>(
-    app: &mut A,
+fn map_user_event<T: 'static>(
+    mut handler: impl FnMut(Event<T>, &RootActiveEventLoop),
     receiver: mpsc::Receiver<T>,
-) -> impl FnMut(Event<HandlePendingUserEvents>, &RootActiveEventLoop) + '_ {
-    move |event, window_target| match event {
-        Event::NewEvents(cause) => app.new_events(window_target, cause),
-        Event::WindowEvent { window_id, event } => {
-            app.window_event(window_target, window_id, event)
-        },
-        Event::DeviceEvent { device_id, event } => {
-            app.device_event(window_target, device_id, event)
-        },
-        Event::UserEvent(_) => {
+) -> impl FnMut(Event<HandlePendingUserEvents>, &RootActiveEventLoop) {
+    move |event, window_target| match event.map_nonuser_event() {
+        Ok(event) => (handler)(event, window_target),
+        Err(_) => {
             for event in receiver.try_iter() {
-                app.user_event(window_target, event);
+                (handler)(Event::UserEvent(event), window_target);
             }
         },
-        Event::Suspended => app.suspended(window_target),
-        Event::Resumed => app.resumed(window_target),
-        Event::AboutToWait => app.about_to_wait(window_target),
-        Event::LoopExiting => app.exiting(window_target),
-        Event::MemoryWarning => app.memory_warning(window_target),
     }
 }
 
@@ -139,6 +138,18 @@ pub struct EventLoop<T: 'static> {
     sender: Sender<T>,
     receiver: Receiver<T>,
     window_target: RootActiveEventLoop,
+
+    // Since iOS 9.0, we no longer need to remove the observers before they are deallocated; the
+    // system instead cleans it up next time it would have posted a notification to it.
+    //
+    // Though we do still need to keep the observers around to prevent them from being deallocated.
+    _did_finish_launching_observer: Retained<NSObject>,
+    _did_become_active_observer: Retained<NSObject>,
+    _will_resign_active_observer: Retained<NSObject>,
+    _will_enter_foreground_observer: Retained<NSObject>,
+    _did_enter_background_observer: Retained<NSObject>,
+    _will_terminate_observer: Retained<NSObject>,
+    _did_receive_memory_warning_observer: Retained<NSObject>,
 }
 
 #[derive(Default, Debug, Copy, Clone, PartialEq, Eq, Hash)]
@@ -165,15 +176,104 @@ impl<T: 'static> EventLoop<T> {
         // this line sets up the main run loop before `UIApplicationMain`
         setup_control_flow_observers();
 
+        let center = unsafe { NSNotificationCenter::defaultCenter() };
+
+        let _did_finish_launching_observer = create_observer(
+            &center,
+            // `application:didFinishLaunchingWithOptions:`
+            unsafe { UIApplicationDidFinishLaunchingNotification },
+            move |_| {
+                app_state::did_finish_launching(mtm);
+            },
+        );
+        let _did_become_active_observer = create_observer(
+            &center,
+            // `applicationDidBecomeActive:`
+            unsafe { UIApplicationDidBecomeActiveNotification },
+            move |_| {
+                app_state::handle_nonuser_event(mtm, EventWrapper::StaticEvent(Event::Resumed));
+            },
+        );
+        let _will_resign_active_observer = create_observer(
+            &center,
+            // `applicationWillResignActive:`
+            unsafe { UIApplicationWillResignActiveNotification },
+            move |_| {
+                app_state::handle_nonuser_event(mtm, EventWrapper::StaticEvent(Event::Suspended));
+            },
+        );
+        let _will_enter_foreground_observer = create_observer(
+            &center,
+            // `applicationWillEnterForeground:`
+            unsafe { UIApplicationWillEnterForegroundNotification },
+            move |notification| {
+                let app = unsafe { notification.object() }.expect(
+                    "UIApplicationWillEnterForegroundNotification to have application object",
+                );
+                // SAFETY: The `object` in `UIApplicationWillEnterForegroundNotification` is
+                // documented to be `UIApplication`.
+                let app: Retained<UIApplication> = unsafe { Retained::cast(app) };
+                send_occluded_event_for_all_windows(&app, false);
+            },
+        );
+        let _did_enter_background_observer = create_observer(
+            &center,
+            // `applicationDidEnterBackground:`
+            unsafe { UIApplicationDidEnterBackgroundNotification },
+            move |notification| {
+                let app = unsafe { notification.object() }.expect(
+                    "UIApplicationDidEnterBackgroundNotification to have application object",
+                );
+                // SAFETY: The `object` in `UIApplicationDidEnterBackgroundNotification` is
+                // documented to be `UIApplication`.
+                let app: Retained<UIApplication> = unsafe { Retained::cast(app) };
+                send_occluded_event_for_all_windows(&app, true);
+            },
+        );
+        let _will_terminate_observer = create_observer(
+            &center,
+            // `applicationWillTerminate:`
+            unsafe { UIApplicationWillTerminateNotification },
+            move |notification| {
+                let app = unsafe { notification.object() }
+                    .expect("UIApplicationWillTerminateNotification to have application object");
+                // SAFETY: The `object` in `UIApplicationWillTerminateNotification` is
+                // (somewhat) documented to be `UIApplication`.
+                let app: Retained<UIApplication> = unsafe { Retained::cast(app) };
+                app_state::terminated(&app);
+            },
+        );
+        let _did_receive_memory_warning_observer = create_observer(
+            &center,
+            // `applicationDidReceiveMemoryWarning:`
+            unsafe { UIApplicationDidReceiveMemoryWarningNotification },
+            move |_| {
+                app_state::handle_nonuser_event(
+                    mtm,
+                    EventWrapper::StaticEvent(Event::MemoryWarning),
+                );
+            },
+        );
+
         Ok(EventLoop {
             mtm,
             sender,
             receiver,
             window_target: RootActiveEventLoop { p: ActiveEventLoop { mtm }, _marker: PhantomData },
+            _did_finish_launching_observer,
+            _did_become_active_observer,
+            _will_resign_active_observer,
+            _will_enter_foreground_observer,
+            _did_enter_background_observer,
+            _will_terminate_observer,
+            _did_receive_memory_warning_observer,
         })
     }
 
-    pub fn run_app<A: ApplicationHandler<T>>(self, app: &mut A) -> ! {
+    pub fn run<F>(self, handler: F) -> !
+    where
+        F: FnMut(Event<T>, &RootActiveEventLoop),
+    {
         let application: Option<Retained<UIApplication>> =
             unsafe { msg_send_id![UIApplication::class(), sharedApplication] };
         assert!(
@@ -183,7 +283,7 @@ impl<T: 'static> EventLoop<T> {
              `EventLoop::run_app` calls `UIApplicationMain` on iOS",
         );
 
-        let handler = map_user_event(app, self.receiver);
+        let handler = map_user_event(handler, self.receiver);
 
         let handler = unsafe {
             std::mem::transmute::<
@@ -196,9 +296,6 @@ impl<T: 'static> EventLoop<T> {
 
         app_state::will_launch(self.mtm, handler);
 
-        // Ensure application delegate is initialized
-        let _ = AppDelegate::class();
-
         extern "C" {
             // These functions are in crt_externs.h.
             fn _NSGetArgc() -> *mut c_int;
@@ -209,8 +306,10 @@ impl<T: 'static> EventLoop<T> {
             UIApplicationMain(
                 *_NSGetArgc(),
                 NonNull::new(*_NSGetArgv()).unwrap(),
+                // We intentionally override neither the application nor the delegate, to allow the
+                // user to do so themselves!
+                None,
                 None,
-                Some(&NSString::from_str(AppDelegate::NAME)),
             )
         };
         unreachable!()
@@ -283,8 +382,7 @@ impl<T> EventLoopProxy<T> {
                 cancel: None,
                 perform: event_loop_proxy_handler,
             };
-            let source =
-                CFRunLoopSourceCreate(ptr::null_mut(), CFIndex::max_value() - 1, &mut context);
+            let source = CFRunLoopSourceCreate(ptr::null_mut(), CFIndex::MAX - 1, &mut context);
             CFRunLoopAddSource(rl, source, kCFRunLoopCommonModes);
             CFRunLoopWakeUp(rl);
 
@@ -367,7 +465,7 @@ fn setup_control_flow_observers() {
             ptr::null_mut(),
             kCFRunLoopAfterWaiting,
             1, // repeat = true
-            CFIndex::min_value(),
+            CFIndex::MIN,
             control_flow_begin_handler,
             ptr::null_mut(),
         );
@@ -387,7 +485,7 @@ fn setup_control_flow_observers() {
             ptr::null_mut(),
             kCFRunLoopExit | kCFRunLoopBeforeWaiting,
             1, // repeat = true
-            CFIndex::max_value(),
+            CFIndex::MAX,
             control_flow_end_handler,
             ptr::null_mut(),
         );

src/platform_impl/ios/mod.rs

@@ -1,10 +1,9 @@
-#![cfg(ios_platform)]
 #![allow(clippy::let_unit_value)]
 
-mod app_delegate;
 mod app_state;
 mod event_loop;
 mod monitor;
+mod notification_center;
 mod view;
 mod view_controller;
 mod window;
@@ -33,7 +32,7 @@ pub(crate) use crate::platform_impl::Fullscreen;
 pub struct DeviceId;
 
 impl DeviceId {
-    pub const unsafe fn dummy() -> Self {
+    pub const fn dummy() -> Self {
         DeviceId
     }
 }

src/platform_impl/ios/monitor.rs

@@ -102,13 +102,20 @@ impl Clone for MonitorHandle {
 
 impl hash::Hash for MonitorHandle {
     fn hash<H: hash::Hasher>(&self, state: &mut H) {
-        (self as *const Self).hash(state);
+        // SAFETY: Only getting the pointer.
+        let mtm = unsafe { MainThreadMarker::new_unchecked() };
+        Retained::as_ptr(self.ui_screen.get(mtm)).hash(state);
     }
 }
 
 impl PartialEq for MonitorHandle {
     fn eq(&self, other: &Self) -> bool {
-        ptr::eq(self, other)
+        // SAFETY: Only getting the pointer.
+        let mtm = unsafe { MainThreadMarker::new_unchecked() };
+        ptr::eq(
+            Retained::as_ptr(self.ui_screen.get(mtm)),
+            Retained::as_ptr(other.ui_screen.get(mtm)),
+        )
     }
 }
 
@@ -122,8 +129,10 @@ impl PartialOrd for MonitorHandle {
 
 impl Ord for MonitorHandle {
     fn cmp(&self, other: &Self) -> std::cmp::Ordering {
+        // SAFETY: Only getting the pointer.
         // TODO: Make a better ordering
-        (self as *const Self).cmp(&(other as *const Self))
+        let mtm = unsafe { MainThreadMarker::new_unchecked() };
+        Retained::as_ptr(self.ui_screen.get(mtm)).cmp(&Retained::as_ptr(other.ui_screen.get(mtm)))
     }
 }
 
@@ -242,3 +251,27 @@ pub fn uiscreens(mtm: MainThreadMarker) -> VecDeque<MonitorHandle> {
     #[allow(deprecated)]
     UIScreen::screens(mtm).into_iter().map(MonitorHandle::new).collect()
 }
+
+#[cfg(test)]
+mod tests {
+    use objc2_foundation::NSSet;
+
+    use super::*;
+
+    // Test that UIScreen pointer comparisons are correct.
+    #[test]
+    #[allow(deprecated)]
+    fn screen_comparisons() {
+        // Test code, doesn't matter that it's not thread safe
+        let mtm = unsafe { MainThreadMarker::new_unchecked() };
+
+        assert!(ptr::eq(&*UIScreen::mainScreen(mtm), &*UIScreen::mainScreen(mtm)));
+
+        let main = UIScreen::mainScreen(mtm);
+        assert!(UIScreen::screens(mtm).iter().any(|screen| ptr::eq(screen, &*main)));
+
+        assert!(unsafe {
+            NSSet::setWithArray(&UIScreen::screens(mtm)).containsObject(&UIScreen::mainScreen(mtm))
+        });
+    }
+}

src/platform_impl/ios/notification_center.rs

@@ -0,0 +1,27 @@
+use std::ptr::NonNull;
+
+use block2::RcBlock;
+use objc2::rc::Retained;
+use objc2_foundation::{NSNotification, NSNotificationCenter, NSNotificationName, NSObject};
+
+/// Observe the given notification.
+///
+/// This is used in Winit as an alternative to declaring an application delegate, as we want to
+/// give the user full control over those.
+pub fn create_observer(
+    center: &NSNotificationCenter,
+    name: &NSNotificationName,
+    handler: impl Fn(&NSNotification) + 'static,
+) -> Retained<NSObject> {
+    let block = RcBlock::new(move |notification: NonNull<NSNotification>| {
+        handler(unsafe { notification.as_ref() });
+    });
+    unsafe {
+        center.addObserverForName_object_queue_usingBlock(
+            Some(name),
+            None, // No sender filter
+            None, // No queue, run on posting thread (i.e. main thread)
+            &block,
+        )
+    }
+}

src/platform_impl/ios/view.rs

@@ -4,19 +4,21 @@ use std::cell::{Cell, RefCell};
 use objc2::rc::Retained;
 use objc2::runtime::{NSObjectProtocol, ProtocolObject};
 use objc2::{declare_class, msg_send, msg_send_id, mutability, sel, ClassType, DeclaredClass};
-use objc2_foundation::{CGFloat, CGPoint, CGRect, MainThreadMarker, NSObject, NSSet};
+use objc2_foundation::{CGFloat, CGPoint, CGRect, MainThreadMarker, NSObject, NSSet, NSString};
 use objc2_ui_kit::{
     UICoordinateSpace, UIEvent, UIForceTouchCapability, UIGestureRecognizer,
-    UIGestureRecognizerDelegate, UIGestureRecognizerState, UIPanGestureRecognizer,
+    UIGestureRecognizerDelegate, UIGestureRecognizerState, UIKeyInput, UIPanGestureRecognizer,
     UIPinchGestureRecognizer, UIResponder, UIRotationGestureRecognizer, UITapGestureRecognizer,
-    UITouch, UITouchPhase, UITouchType, UITraitEnvironment, UIView,
+    UITextInputTraits, UITouch, UITouchPhase, UITouchType, UITraitEnvironment, UIView,
 };
 
 use super::app_state::{self, EventWrapper};
 use super::window::WinitUIWindow;
 use crate::dpi::PhysicalPosition;
-use crate::event::{Event, Force, Touch, TouchPhase, WindowEvent};
+use crate::event::{ElementState, Event, Force, KeyEvent, Touch, TouchPhase, WindowEvent};
+use crate::keyboard::{Key, KeyCode, KeyLocation, NamedKey, NativeKeyCode, PhysicalKey};
 use crate::platform_impl::platform::DEVICE_ID;
+use crate::platform_impl::KeyEventExtra;
 use crate::window::{WindowAttributes, WindowId as RootWindowId};
 
 pub struct WinitViewState {
@@ -188,7 +190,7 @@ declare_class!(
                     // Pass -delta so that action is reversed
                     (TouchPhase::Cancelled, -recognizer.scale())
                 }
-                state => panic!("unexpected recognizer state: {:?}", state),
+                state => panic!("unexpected recognizer state: {state:?}"),
             };
 
             let gesture_event = EventWrapper::StaticEvent(Event::WindowEvent {
@@ -247,7 +249,7 @@ declare_class!(
                     // Pass -delta so that action is reversed
                     (TouchPhase::Cancelled, -recognizer.rotation())
                 }
-                state => panic!("unexpected recognizer state: {:?}", state),
+                state => panic!("unexpected recognizer state: {state:?}"),
             };
 
             // Make delta negative to match macos, convert to degrees
@@ -298,7 +300,7 @@ declare_class!(
                     // Pass -delta so that action is reversed
                     (TouchPhase::Cancelled, -last_pan.x, -last_pan.y)
                 }
-                state => panic!("unexpected recognizer state: {:?}", state),
+                state => panic!("unexpected recognizer state: {state:?}"),
             };
 
 
@@ -314,6 +316,11 @@ declare_class!(
             let mtm = MainThreadMarker::new().unwrap();
             app_state::handle_nonuser_event(mtm, gesture_event);
         }
+
+        #[method(canBecomeFirstResponder)]
+        fn can_become_first_responder(&self) -> bool {
+            true
+        }
     }
 
     unsafe impl NSObjectProtocol for WinitView {}
@@ -324,6 +331,26 @@ declare_class!(
             true
         }
     }
+
+    unsafe impl UITextInputTraits for WinitView {
+    }
+
+    unsafe impl UIKeyInput for WinitView {
+        #[method(hasText)]
+        fn has_text(&self) -> bool {
+            true
+        }
+
+        #[method(insertText:)]
+        fn insert_text(&self, text: &NSString) {
+            self.handle_insert_text(text)
+        }
+
+        #[method(deleteBackward)]
+        fn delete_backward(&self) {
+            self.handle_delete_backward()
+        }
+    }
 );
 
 impl WinitView {
@@ -512,4 +539,69 @@ impl WinitView {
         let mtm = MainThreadMarker::new().unwrap();
         app_state::handle_nonuser_events(mtm, touch_events);
     }
+
+    fn handle_insert_text(&self, text: &NSString) {
+        let window = self.window().unwrap();
+        let window_id = RootWindowId(window.id());
+        let mtm = MainThreadMarker::new().unwrap();
+        // send individual events for each character
+        app_state::handle_nonuser_events(
+            mtm,
+            text.to_string().chars().flat_map(|c| {
+                let text = smol_str::SmolStr::from_iter([c]);
+                // Emit both press and release events
+                [ElementState::Pressed, ElementState::Released].map(|state| {
+                    EventWrapper::StaticEvent(Event::WindowEvent {
+                        window_id,
+                        event: WindowEvent::KeyboardInput {
+                            event: KeyEvent {
+                                text: if state == ElementState::Pressed {
+                                    Some(text.clone())
+                                } else {
+                                    None
+                                },
+                                state,
+                                location: KeyLocation::Standard,
+                                repeat: false,
+                                logical_key: Key::Character(text.clone()),
+                                physical_key: PhysicalKey::Unidentified(
+                                    NativeKeyCode::Unidentified,
+                                ),
+                                platform_specific: KeyEventExtra {},
+                            },
+                            is_synthetic: false,
+                            device_id: DEVICE_ID,
+                        },
+                    })
+                })
+            }),
+        );
+    }
+
+    fn handle_delete_backward(&self) {
+        let window = self.window().unwrap();
+        let window_id = RootWindowId(window.id());
+        let mtm = MainThreadMarker::new().unwrap();
+        app_state::handle_nonuser_events(
+            mtm,
+            [ElementState::Pressed, ElementState::Released].map(|state| {
+                EventWrapper::StaticEvent(Event::WindowEvent {
+                    window_id,
+                    event: WindowEvent::KeyboardInput {
+                        device_id: DEVICE_ID,
+                        event: KeyEvent {
+                            state,
+                            logical_key: Key::Named(NamedKey::Backspace),
+                            physical_key: PhysicalKey::Code(KeyCode::Backspace),
+                            platform_specific: KeyEventExtra {},
+                            repeat: false,
+                            location: KeyLocation::Standard,
+                            text: None,
+                        },
+                        is_synthetic: false,
+                    },
+                })
+            }),
+        );
+    }
 }

src/platform_impl/ios/window.rs

@@ -367,12 +367,24 @@ impl Inner {
         warn!("`Window::set_ime_cursor_area` is ignored on iOS")
     }
 
-    pub fn set_ime_allowed(&self, _allowed: bool) {
-        warn!("`Window::set_ime_allowed` is ignored on iOS")
+    /// Show / hide the keyboard. To show the keyboard, we call `becomeFirstResponder`,
+    /// requesting focus for the [WinitView]. Since [WinitView] implements
+    /// [objc2_ui_kit::UIKeyInput], the keyboard will be shown.
+    /// <https://developer.apple.com/documentation/uikit/uiresponder/1621113-becomefirstresponder>
+    pub fn set_ime_allowed(&self, allowed: bool) {
+        if allowed {
+            unsafe {
+                self.view.becomeFirstResponder();
+            }
+        } else {
+            unsafe {
+                self.view.resignFirstResponder();
+            }
+        }
     }
 
     pub fn set_ime_purpose(&self, _purpose: ImePurpose) {
-        warn!("`Window::set_ime_allowed` is ignored on iOS")
+        warn!("`Window::set_ime_purpose` is ignored on iOS")
     }
 
     pub fn focus_window(&self) {
@@ -701,7 +713,7 @@ pub struct WindowId {
 }
 
 impl WindowId {
-    pub const unsafe fn dummy() -> Self {
+    pub const fn dummy() -> Self {
         WindowId { window: std::ptr::null_mut() }
     }
 }

src/platform_impl/linux/common/xkb/mod.rs

@@ -184,7 +184,7 @@ pub struct KeyContext<'a> {
     scratch_buffer: &'a mut Vec<u8>,
 }
 
-impl<'a> KeyContext<'a> {
+impl KeyContext<'_> {
     pub fn process_key_event(
         &mut self,
         keycode: u32,
@@ -320,7 +320,7 @@ impl<'a, 'b> KeyEventResults<'a, 'b> {
 
     // The current behaviour makes it so composing a character overrides attempts to input a
     // control character with the `Ctrl` key. We can potentially add a configuration option
-    // if someone specifically wants the oppsite behaviour.
+    // if someone specifically wants the opposite behaviour.
     pub fn text_with_all_modifiers(&mut self) -> Option<SmolStr> {
         match self.composed_text() {
             Ok(text) => text,

src/platform_impl/linux/mod.rs

@@ -11,8 +11,6 @@ use std::{env, fmt};
 #[cfg(x11_platform)]
 use std::{ffi::CStr, mem::MaybeUninit, os::raw::*, sync::Mutex};
 
-use crate::application::ApplicationHandler;
-use crate::platform::pump_events::PumpStatus;
 #[cfg(x11_platform)]
 use crate::utils::Lazy;
 use smol_str::SmolStr;
@@ -21,9 +19,12 @@ use smol_str::SmolStr;
 use self::x11::{X11Error, XConnection, XError, XNotSupported};
 use crate::dpi::{PhysicalPosition, PhysicalSize, Position, Size};
 use crate::error::{EventLoopError, ExternalError, NotSupportedError, OsError as RootOsError};
-use crate::event_loop::{AsyncRequestSerial, ControlFlow, DeviceEvents, EventLoopClosed};
+use crate::event_loop::{
+    ActiveEventLoop as RootELW, AsyncRequestSerial, ControlFlow, DeviceEvents, EventLoopClosed,
+};
 use crate::icon::Icon;
 use crate::keyboard::Key;
+use crate::platform::pump_events::PumpStatus;
 #[cfg(x11_platform)]
 use crate::platform::x11::{WindowType as XWindowType, XlibErrorHook};
 use crate::window::{
@@ -116,6 +117,8 @@ pub(crate) static X11_BACKEND: Lazy<Mutex<Result<Arc<XConnection>, XNotSupported
 pub enum OsError {
     Misc(&'static str),
     #[cfg(x11_platform)]
+    XNotSupported(XNotSupported),
+    #[cfg(x11_platform)]
     XError(Arc<X11Error>),
     #[cfg(wayland_platform)]
     WaylandError(Arc<wayland::WaylandError>),
@@ -126,6 +129,8 @@ impl fmt::Display for OsError {
         match *self {
             OsError::Misc(e) => _f.pad(e),
             #[cfg(x11_platform)]
+            OsError::XNotSupported(ref e) => fmt::Display::fmt(e, _f),
+            #[cfg(x11_platform)]
             OsError::XError(ref e) => fmt::Display::fmt(e, _f),
             #[cfg(wayland_platform)]
             OsError::WaylandError(ref e) => fmt::Display::fmt(e, _f),
@@ -156,7 +161,7 @@ impl From<u64> for WindowId {
 }
 
 impl WindowId {
-    pub const unsafe fn dummy() -> Self {
+    pub const fn dummy() -> Self {
         Self(0)
     }
 }
@@ -170,11 +175,11 @@ pub enum DeviceId {
 }
 
 impl DeviceId {
-    pub const unsafe fn dummy() -> Self {
+    pub const fn dummy() -> Self {
         #[cfg(wayland_platform)]
-        return DeviceId::Wayland(unsafe { wayland::DeviceId::dummy() });
+        return DeviceId::Wayland(wayland::DeviceId::dummy());
         #[cfg(all(not(wayland_platform), x11_platform))]
-        return DeviceId::X(unsafe { x11::DeviceId::dummy() });
+        return DeviceId::X(x11::DeviceId::dummy());
     }
 }
 
@@ -642,18 +647,18 @@ pub(crate) enum PlatformCustomCursor {
 
 /// Hooks for X11 errors.
 #[cfg(x11_platform)]
-pub(crate) static mut XLIB_ERROR_HOOKS: Mutex<Vec<XlibErrorHook>> = Mutex::new(Vec::new());
+pub(crate) static XLIB_ERROR_HOOKS: Mutex<Vec<XlibErrorHook>> = Mutex::new(Vec::new());
 
 #[cfg(x11_platform)]
 unsafe extern "C" fn x_error_callback(
     display: *mut x11::ffi::Display,
     event: *mut x11::ffi::XErrorEvent,
 ) -> c_int {
-    let xconn_lock = X11_BACKEND.lock().unwrap();
+    let xconn_lock = X11_BACKEND.lock().unwrap_or_else(|e| e.into_inner());
     if let Ok(ref xconn) = *xconn_lock {
         // Call all the hooks.
         let mut error_handled = false;
-        for hook in unsafe { XLIB_ERROR_HOOKS.lock() }.unwrap().iter() {
+        for hook in XLIB_ERROR_HOOKS.lock().unwrap().iter() {
             error_handled |= hook(display as *mut _, event as *mut _);
         }
 
@@ -691,6 +696,7 @@ unsafe extern "C" fn x_error_callback(
     0
 }
 
+#[allow(clippy::large_enum_variant)]
 pub enum EventLoop<T: 'static> {
     #[cfg(wayland_platform)]
     Wayland(Box<wayland::EventLoop<T>>),
@@ -763,9 +769,9 @@ impl<T: 'static> EventLoop<T> {
         // Create the display based on the backend.
         match backend {
             #[cfg(wayland_platform)]
-            Backend::Wayland => EventLoop::new_wayland_any_thread().map_err(Into::into),
+            Backend::Wayland => EventLoop::new_wayland_any_thread(),
             #[cfg(x11_platform)]
-            Backend::X => EventLoop::new_x11_any_thread().map_err(Into::into),
+            Backend::X => EventLoop::new_x11_any_thread(),
         }
     }
 
@@ -776,9 +782,11 @@ impl<T: 'static> EventLoop<T> {
 
     #[cfg(x11_platform)]
     fn new_x11_any_thread() -> Result<EventLoop<T>, EventLoopError> {
-        let xconn = match X11_BACKEND.lock().unwrap().as_ref() {
+        let xconn = match X11_BACKEND.lock().unwrap_or_else(|e| e.into_inner()).as_ref() {
             Ok(xconn) => xconn.clone(),
-            Err(_) => return Err(EventLoopError::NotSupported(NotSupportedError::new())),
+            Err(err) => {
+                return Err(EventLoopError::Os(os_error!(OsError::XNotSupported(err.clone()))))
+            },
         };
 
         Ok(EventLoop::X(x11::EventLoop::new(xconn)))
@@ -798,23 +806,25 @@ impl<T: 'static> EventLoop<T> {
         x11_or_wayland!(match self; EventLoop(evlp) => evlp.create_proxy(); as EventLoopProxy)
     }
 
-    pub fn run_app<A: ApplicationHandler<T>>(self, app: &mut A) -> Result<(), EventLoopError> {
-        x11_or_wayland!(match self; EventLoop(evlp) => evlp.run_app(app))
+    pub fn run<F>(mut self, callback: F) -> Result<(), EventLoopError>
+    where
+        F: FnMut(crate::event::Event<T>, &RootELW),
+    {
+        self.run_on_demand(callback)
     }
 
-    pub fn run_app_on_demand<A: ApplicationHandler<T>>(
-        &mut self,
-        app: &mut A,
-    ) -> Result<(), EventLoopError> {
-        x11_or_wayland!(match self; EventLoop(evlp) => evlp.run_app_on_demand(app))
+    pub fn run_on_demand<F>(&mut self, callback: F) -> Result<(), EventLoopError>
+    where
+        F: FnMut(crate::event::Event<T>, &RootELW),
+    {
+        x11_or_wayland!(match self; EventLoop(evlp) => evlp.run_on_demand(callback))
     }
 
-    pub fn pump_app_events<A: ApplicationHandler<T>>(
-        &mut self,
-        timeout: Option<Duration>,
-        app: &mut A,
-    ) -> PumpStatus {
-        x11_or_wayland!(match self; EventLoop(evlp) => evlp.pump_app_events(timeout, app))
+    pub fn pump_events<F>(&mut self, timeout: Option<Duration>, callback: F) -> PumpStatus
+    where
+        F: FnMut(crate::event::Event<T>, &RootELW),
+    {
+        x11_or_wayland!(match self; EventLoop(evlp) => evlp.pump_events(timeout, callback))
     }
 
     pub fn window_target(&self) -> &crate::event_loop::ActiveEventLoop {
@@ -840,6 +850,7 @@ impl<T: 'static> EventLoopProxy<T> {
     }
 }
 
+#[allow(clippy::large_enum_variant)]
 pub enum ActiveEventLoop {
     #[cfg(wayland_platform)]
     Wayland(wayland::ActiveEventLoop),
@@ -894,6 +905,11 @@ impl ActiveEventLoop {
         x11_or_wayland!(match self; Self(evlp) => evlp.raw_display_handle_rwh_05())
     }
 
+    #[inline]
+    pub fn system_theme(&self) -> Option<Theme> {
+        None
+    }
+
     #[cfg(feature = "rwh_06")]
     #[inline]
     pub fn raw_display_handle_rwh_06(

src/platform_impl/linux/wayland/event_loop/mod.rs

@@ -4,17 +4,22 @@ use std::cell::{Cell, RefCell};
 use std::io::Result as IOResult;
 use std::marker::PhantomData;
 use std::mem;
+use std::os::fd::OwnedFd;
 use std::os::unix::io::{AsFd, AsRawFd, BorrowedFd, RawFd};
 use std::rc::Rc;
 use std::sync::atomic::Ordering;
-use std::sync::{Arc, Mutex};
+use std::sync::{Arc, Condvar, Mutex};
+use std::thread::JoinHandle;
 use std::time::{Duration, Instant};
 
+use calloop::ping::Ping;
+use rustix::event::{PollFd, PollFlags};
+use rustix::pipe::{self, PipeFlags};
 use sctk::reexports::calloop::Error as CalloopError;
 use sctk::reexports::calloop_wayland_source::WaylandSource;
 use sctk::reexports::client::{globals, Connection, QueueHandle};
+use tracing::warn;
 
-use crate::application::ApplicationHandler;
 use crate::cursor::OnlyCursorImage;
 use crate::dpi::LogicalSize;
 use crate::error::{EventLoopError, OsError as RootOsError};
@@ -69,6 +74,8 @@ pub struct EventLoop<T: 'static> {
     // XXX drop after everything else, just to be safe.
     /// Calloop's event loop.
     event_loop: calloop::EventLoop<'static, WinitState>,
+
+    pump_event_notifier: Option<PumpEventNotifier>,
 }
 
 impl<T: 'static> EventLoop<T> {
@@ -169,21 +176,18 @@ impl<T: 'static> EventLoop<T> {
                 p: PlatformActiveEventLoop::Wayland(window_target),
                 _marker: PhantomData,
             },
+            pump_event_notifier: None,
         };
 
         Ok(event_loop)
     }
 
-    pub fn run_app<A: ApplicationHandler<T>>(mut self, app: &mut A) -> Result<(), EventLoopError> {
-        self.run_app_on_demand(app)
-    }
-
-    pub fn run_app_on_demand<A: ApplicationHandler<T>>(
-        &mut self,
-        app: &mut A,
-    ) -> Result<(), EventLoopError> {
+    pub fn run_on_demand<F>(&mut self, mut event_handler: F) -> Result<(), EventLoopError>
+    where
+        F: FnMut(Event<T>, &RootActiveEventLoop),
+    {
         let exit = loop {
-            match self.pump_app_events(None, app) {
+            match self.pump_events(None, &mut event_handler) {
                 PumpStatus::Exit(0) => {
                     break Ok(());
                 },
@@ -205,39 +209,58 @@ impl<T: 'static> EventLoop<T> {
         exit
     }
 
-    pub fn pump_app_events<A: ApplicationHandler<T>>(
-        &mut self,
-        timeout: Option<Duration>,
-        app: &mut A,
-    ) -> PumpStatus {
+    pub fn pump_events<F>(&mut self, timeout: Option<Duration>, mut callback: F) -> PumpStatus
+    where
+        F: FnMut(Event<T>, &RootActiveEventLoop),
+    {
         if !self.loop_running {
             self.loop_running = true;
 
             // Run the initial loop iteration.
-            self.single_iteration(app, StartCause::Init);
+            self.single_iteration(&mut callback, StartCause::Init);
         }
 
         // Consider the possibility that the `StartCause::Init` iteration could
         // request to Exit.
         if !self.exiting() {
-            self.poll_events_with_timeout(timeout, app);
+            self.poll_events_with_timeout(timeout, &mut callback);
         }
         if let Some(code) = self.exit_code() {
             self.loop_running = false;
 
-            app.exiting(&self.window_target);
+            callback(Event::LoopExiting, self.window_target());
 
             PumpStatus::Exit(code)
         } else {
+            // NOTE: spawn a wake-up thread, thus if we have code reading the wayland connection
+            // in parallel to winit, we ensure that the loop itself is marked as having events.
+            if timeout.is_some() && self.pump_event_notifier.is_none() {
+                let awakener = match &self.window_target.p {
+                    PlatformActiveEventLoop::Wayland(window_target) => {
+                        window_target.event_loop_awakener.clone()
+                    },
+                    #[cfg(x11_platform)]
+                    PlatformActiveEventLoop::X(_) => unreachable!(),
+                };
+
+                self.pump_event_notifier =
+                    Some(PumpEventNotifier::spawn(self.connection.clone(), awakener));
+            }
+
+            if let Some(pump_event_notifier) = self.pump_event_notifier.as_ref() {
+                // Notify that we don't have to wait, since we're out of winit.
+                *pump_event_notifier.control.0.lock().unwrap() = PumpEventNotifierAction::Monitor;
+                pump_event_notifier.control.1.notify_one();
+            }
+
             PumpStatus::Continue
         }
     }
 
-    pub fn poll_events_with_timeout<A: ApplicationHandler<T>>(
-        &mut self,
-        mut timeout: Option<Duration>,
-        app: &mut A,
-    ) {
+    pub fn poll_events_with_timeout<F>(&mut self, mut timeout: Option<Duration>, mut callback: F)
+    where
+        F: FnMut(Event<T>, &RootActiveEventLoop),
+    {
         let cause = loop {
             let start = Instant::now();
 
@@ -292,17 +315,23 @@ impl<T: 'static> EventLoop<T> {
 
             // Reduce spurious wake-ups.
             let dispatched_events = self.with_state(|state| state.dispatched_events);
-            if matches!(cause, StartCause::WaitCancelled { .. }) && !dispatched_events {
+            if matches!(cause, StartCause::WaitCancelled { .. })
+                && !dispatched_events
+                && timeout.is_none()
+            {
                 continue;
             }
 
             break cause;
         };
 
-        self.single_iteration(app, cause);
+        self.single_iteration(&mut callback, cause);
     }
 
-    fn single_iteration<A: ApplicationHandler<T>>(&mut self, app: &mut A, cause: StartCause) {
+    fn single_iteration<F>(&mut self, callback: &mut F, cause: StartCause)
+    where
+        F: FnMut(Event<T>, &RootActiveEventLoop),
+    {
         // NOTE currently just indented to simplify the diff
 
         // We retain these grow-only scratch buffers as part of the EventLoop
@@ -313,18 +342,18 @@ impl<T: 'static> EventLoop<T> {
         let mut buffer_sink = std::mem::take(&mut self.buffer_sink);
         let mut window_ids = std::mem::take(&mut self.window_ids);
 
-        app.new_events(&self.window_target, cause);
+        callback(Event::NewEvents(cause), &self.window_target);
 
         // NB: For consistency all platforms must emit a 'resumed' event even though Wayland
         // applications don't themselves have a formal suspend/resume lifecycle.
         if cause == StartCause::Init {
-            app.resumed(&self.window_target);
+            callback(Event::Resumed, &self.window_target);
         }
 
         // Handle pending user events. We don't need back buffer, since we can't dispatch
         // user events indirectly via callback to the user.
         for user_event in self.pending_user_events.borrow_mut().drain(..) {
-            app.user_event(&self.window_target, user_event);
+            callback(Event::UserEvent(user_event), &self.window_target);
         }
 
         // Drain the pending compositor updates.
@@ -345,13 +374,18 @@ impl<T: 'static> EventLoop<T> {
                 let old_physical_size = physical_size;
 
                 let new_inner_size = Arc::new(Mutex::new(physical_size));
-                let root_window_id = crate::window::WindowId(window_id);
-                let event = WindowEvent::ScaleFactorChanged {
-                    scale_factor,
-                    inner_size_writer: InnerSizeWriter::new(Arc::downgrade(&new_inner_size)),
-                };
-
-                app.window_event(&self.window_target, root_window_id, event);
+                callback(
+                    Event::WindowEvent {
+                        window_id: crate::window::WindowId(window_id),
+                        event: WindowEvent::ScaleFactorChanged {
+                            scale_factor,
+                            inner_size_writer: InnerSizeWriter::new(Arc::downgrade(
+                                &new_inner_size,
+                            )),
+                        },
+                    },
+                    &self.window_target,
+                );
 
                 let physical_size = *new_inner_size.lock().unwrap();
                 drop(new_inner_size);
@@ -394,14 +428,23 @@ impl<T: 'static> EventLoop<T> {
                     size
                 });
 
-                let window_id = crate::window::WindowId(window_id);
-                let event = WindowEvent::Resized(physical_size);
-                app.window_event(&self.window_target, window_id, event);
+                callback(
+                    Event::WindowEvent {
+                        window_id: crate::window::WindowId(window_id),
+                        event: WindowEvent::Resized(physical_size),
+                    },
+                    &self.window_target,
+                );
             }
 
             if compositor_update.close_window {
-                let window_id = crate::window::WindowId(window_id);
-                app.window_event(&self.window_target, window_id, WindowEvent::CloseRequested);
+                callback(
+                    Event::WindowEvent {
+                        window_id: crate::window::WindowId(window_id),
+                        event: WindowEvent::CloseRequested,
+                    },
+                    &self.window_target,
+                );
             }
         }
 
@@ -410,15 +453,8 @@ impl<T: 'static> EventLoop<T> {
             buffer_sink.append(&mut state.window_events_sink.lock().unwrap());
         });
         for event in buffer_sink.drain() {
-            match event {
-                Event::WindowEvent { window_id, event } => {
-                    app.window_event(&self.window_target, window_id, event)
-                },
-                Event::DeviceEvent { device_id, event } => {
-                    app.device_event(&self.window_target, device_id, event)
-                },
-                _ => unreachable!("event which is neither device nor window event."),
-            }
+            let event = event.map_nonuser_event().unwrap();
+            callback(event, &self.window_target);
         }
 
         // Handle non-synthetic events.
@@ -426,15 +462,8 @@ impl<T: 'static> EventLoop<T> {
             buffer_sink.append(&mut state.events_sink);
         });
         for event in buffer_sink.drain() {
-            match event {
-                Event::WindowEvent { window_id, event } => {
-                    app.window_event(&self.window_target, window_id, event)
-                },
-                Event::DeviceEvent { device_id, event } => {
-                    app.device_event(&self.window_target, device_id, event)
-                },
-                _ => unreachable!("event which is neither device nor window event."),
-            }
+            let event = event.map_nonuser_event().unwrap();
+            callback(event, &self.window_target);
         }
 
         // Collect the window ids
@@ -470,8 +499,10 @@ impl<T: 'static> EventLoop<T> {
             });
 
             if let Some(event) = event {
-                let window_id = crate::window::WindowId(*window_id);
-                app.window_event(&self.window_target, window_id, event);
+                callback(
+                    Event::WindowEvent { window_id: crate::window::WindowId(*window_id), event },
+                    &self.window_target,
+                );
             }
         }
 
@@ -481,7 +512,7 @@ impl<T: 'static> EventLoop<T> {
         });
 
         // This is always the last event we dispatch before poll again
-        app.about_to_wait(&self.window_target);
+        callback(Event::AboutToWait, &self.window_target);
 
         // Update the window frames and schedule redraws.
         let mut wake_up = false;
@@ -602,7 +633,7 @@ impl<T> AsRawFd for EventLoop<T> {
 
 pub struct ActiveEventLoop {
     /// The event loop wakeup source.
-    pub event_loop_awakener: calloop::ping::Ping,
+    pub event_loop_awakener: Ping,
 
     /// The main queue used by the event loop.
     pub queue_handle: QueueHandle<WinitState>,
@@ -686,3 +717,94 @@ impl ActiveEventLoop {
         .into())
     }
 }
+
+#[derive(Debug)]
+struct PumpEventNotifier {
+    /// Whether we're in winit or not.
+    control: Arc<(Mutex<PumpEventNotifierAction>, Condvar)>,
+    /// Waker handle for the working thread.
+    worker_waker: Option<OwnedFd>,
+    /// Thread handle.
+    handle: Option<JoinHandle<()>>,
+}
+
+impl Drop for PumpEventNotifier {
+    fn drop(&mut self) {
+        // Wake-up the thread.
+        if let Some(worker_waker) = self.worker_waker.as_ref() {
+            let _ = rustix::io::write(worker_waker.as_fd(), &[0u8]);
+        }
+        *self.control.0.lock().unwrap() = PumpEventNotifierAction::Shutdown;
+        self.control.1.notify_one();
+
+        if let Some(handle) = self.handle.take() {
+            let _ = handle.join();
+        }
+    }
+}
+
+impl PumpEventNotifier {
+    fn spawn(connection: Connection, awakener: Ping) -> Self {
+        // Start from the waiting state.
+        let control = Arc::new((Mutex::new(PumpEventNotifierAction::Pause), Condvar::new()));
+        let control_thread = Arc::clone(&control);
+
+        let (read, write) = match pipe::pipe_with(PipeFlags::CLOEXEC | PipeFlags::NONBLOCK) {
+            Ok((read, write)) => (read, write),
+            Err(_) => return Self { control, handle: None, worker_waker: None },
+        };
+
+        let handle =
+            std::thread::Builder::new().name(String::from("pump_events mon")).spawn(move || {
+                let (lock, cvar) = &*control_thread;
+                'outer: loop {
+                    let mut wait = lock.lock().unwrap();
+                    while *wait == PumpEventNotifierAction::Pause {
+                        wait = cvar.wait(wait).unwrap();
+                    }
+
+                    // Exit the loop when we're asked to. Given that we poll
+                    // only once we can take the `prepare_read`, but in some cases
+                    // it could be not possible, we may block on `join`.
+                    if *wait == PumpEventNotifierAction::Shutdown {
+                        break 'outer;
+                    }
+
+                    // Wake-up the main loop and put this one back to sleep.
+                    *wait = PumpEventNotifierAction::Pause;
+                    drop(wait);
+
+                    while let Some(read_guard) = connection.prepare_read() {
+                        let _ = connection.flush();
+                        let poll_fd = PollFd::from_borrowed_fd(connection.as_fd(), PollFlags::IN);
+                        let pipe_poll_fd = PollFd::from_borrowed_fd(read.as_fd(), PollFlags::IN);
+                        // Read from the `fd` before going back to poll.
+                        if Ok(1) == rustix::io::read(read.as_fd(), &mut [0u8; 1]) {
+                            break 'outer;
+                        }
+                        let _ = rustix::event::poll(&mut [poll_fd, pipe_poll_fd], -1);
+                        // Non-blocking read the connection.
+                        let _ = read_guard.read_without_dispatch();
+                    }
+
+                    awakener.ping();
+                }
+            });
+
+        if let Some(err) = handle.as_ref().err() {
+            warn!("failed to spawn pump_events wake-up thread: {err}");
+        }
+
+        PumpEventNotifier { control, handle: handle.ok(), worker_waker: Some(write) }
+    }
+}
+
+#[derive(Debug, PartialEq, Eq)]
+enum PumpEventNotifierAction {
+    /// Monitor the wayland queue.
+    Monitor,
+    /// Pause monitoring.
+    Pause,
+    /// Shutdown the thread.
+    Shutdown,
+}

src/platform_impl/linux/wayland/mod.rs

@@ -1,5 +1,3 @@
-#![cfg(wayland_platform)]
-
 //! Winit's Wayland backend.
 
 use std::fmt::Display;
@@ -68,7 +66,7 @@ impl From<WaylandError> for OsError {
 pub struct DeviceId;
 
 impl DeviceId {
-    pub const unsafe fn dummy() -> Self {
+    pub const fn dummy() -> Self {
         DeviceId
     }
 }

src/platform_impl/linux/wayland/seat/keyboard/mod.rs

@@ -18,7 +18,6 @@ use crate::keyboard::ModifiersState;
 
 use crate::platform_impl::common::xkb::Context;
 use crate::platform_impl::wayland::event_loop::sink::EventSink;
-use crate::platform_impl::wayland::seat::WinitSeatState;
 use crate::platform_impl::wayland::state::WinitState;
 use crate::platform_impl::wayland::{self, DeviceId, WindowId};
 
@@ -33,7 +32,17 @@ impl Dispatch<WlKeyboard, KeyboardData, WinitState> for WinitState {
     ) {
         let seat_state = match state.seats.get_mut(&data.seat.id()) {
             Some(seat_state) => seat_state,
-            None => return,
+            None => {
+                warn!("Received keyboard event {event:?} without seat");
+                return;
+            },
+        };
+        let keyboard_state = match seat_state.keyboard_state.as_mut() {
+            Some(keyboard_state) => keyboard_state,
+            None => {
+                warn!("Received keyboard event {event:?} without keyboard");
+                return;
+            },
         };
 
         match event {
@@ -43,7 +52,7 @@ impl Dispatch<WlKeyboard, KeyboardData, WinitState> for WinitState {
                         warn!("non-xkb compatible keymap")
                     },
                     WlKeymapFormat::XkbV1 => {
-                        let context = &mut seat_state.keyboard_state.as_mut().unwrap().xkb_context;
+                        let context = &mut keyboard_state.xkb_context;
                         context.set_keymap_from_fd(fd, size as usize);
                     },
                     _ => unreachable!(),
@@ -67,7 +76,6 @@ impl Dispatch<WlKeyboard, KeyboardData, WinitState> for WinitState {
                 };
 
                 // Drop the repeat, if there were any.
-                let keyboard_state = seat_state.keyboard_state.as_mut().unwrap();
                 keyboard_state.current_repeat = None;
                 if let Some(token) = keyboard_state.repeat_token.take() {
                     keyboard_state.loop_handle.remove(token);
@@ -91,9 +99,8 @@ impl Dispatch<WlKeyboard, KeyboardData, WinitState> for WinitState {
             WlKeyboardEvent::Leave { surface, .. } => {
                 let window_id = wayland::make_wid(&surface);
 
-                // NOTE: we should drop the repeat regardless whethere it was for the present
+                // NOTE: we should drop the repeat regardless whether it was for the present
                 // window of for the window which just went gone.
-                let keyboard_state = seat_state.keyboard_state.as_mut().unwrap();
                 keyboard_state.current_repeat = None;
                 if let Some(token) = keyboard_state.repeat_token.take() {
                     keyboard_state.loop_handle.remove(token);
@@ -128,7 +135,7 @@ impl Dispatch<WlKeyboard, KeyboardData, WinitState> for WinitState {
                 let key = key + 8;
 
                 key_input(
-                    seat_state,
+                    keyboard_state,
                     &mut state.events_sink,
                     data,
                     key,
@@ -136,7 +143,6 @@ impl Dispatch<WlKeyboard, KeyboardData, WinitState> for WinitState {
                     false,
                 );
 
-                let keyboard_state = seat_state.keyboard_state.as_mut().unwrap();
                 let delay = match keyboard_state.repeat_info {
                     RepeatInfo::Repeat { delay, .. } => delay,
                     RepeatInfo::Disable => return,
@@ -163,18 +169,25 @@ impl Dispatch<WlKeyboard, KeyboardData, WinitState> for WinitState {
                         state.dispatched_events = true;
 
                         let data = wl_keyboard.data::<KeyboardData>().unwrap();
-                        let seat_state = state.seats.get_mut(&data.seat.id()).unwrap();
+                        let seat_state = match state.seats.get_mut(&data.seat.id()) {
+                            Some(seat_state) => seat_state,
+                            None => return TimeoutAction::Drop,
+                        };
 
-                        // NOTE: The removed on event source is batched, but key change to
-                        // `None` is instant.
-                        let repeat_keycode =
-                            match seat_state.keyboard_state.as_ref().unwrap().current_repeat {
-                                Some(repeat_keycode) => repeat_keycode,
-                                None => return TimeoutAction::Drop,
-                            };
+                        let keyboard_state = match seat_state.keyboard_state.as_mut() {
+                            Some(keyboard_state) => keyboard_state,
+                            None => return TimeoutAction::Drop,
+                        };
+
+                        // NOTE: The removed on event source is batched, but key change to `None`
+                        // is instant.
+                        let repeat_keycode = match keyboard_state.current_repeat {
+                            Some(repeat_keycode) => repeat_keycode,
+                            None => return TimeoutAction::Drop,
+                        };
 
                         key_input(
-                            seat_state,
+                            keyboard_state,
                             &mut state.events_sink,
                             data,
                             repeat_keycode,
@@ -183,7 +196,7 @@ impl Dispatch<WlKeyboard, KeyboardData, WinitState> for WinitState {
                         );
 
                         // NOTE: the gap could change dynamically while repeat is going.
-                        match seat_state.keyboard_state.as_ref().unwrap().repeat_info {
+                        match keyboard_state.repeat_info {
                             RepeatInfo::Repeat { gap, .. } => TimeoutAction::ToDuration(gap),
                             RepeatInfo::Disable => TimeoutAction::Drop,
                         }
@@ -194,7 +207,7 @@ impl Dispatch<WlKeyboard, KeyboardData, WinitState> for WinitState {
                 let key = key + 8;
 
                 key_input(
-                    seat_state,
+                    keyboard_state,
                     &mut state.events_sink,
                     data,
                     key,
@@ -202,7 +215,6 @@ impl Dispatch<WlKeyboard, KeyboardData, WinitState> for WinitState {
                     false,
                 );
 
-                let keyboard_state = seat_state.keyboard_state.as_mut().unwrap();
                 if keyboard_state.repeat_info != RepeatInfo::Disable
                     && keyboard_state.xkb_context.keymap_mut().unwrap().key_repeats(key)
                     && Some(key) == keyboard_state.current_repeat
@@ -216,7 +228,7 @@ impl Dispatch<WlKeyboard, KeyboardData, WinitState> for WinitState {
             WlKeyboardEvent::Modifiers {
                 mods_depressed, mods_latched, mods_locked, group, ..
             } => {
-                let xkb_context = &mut seat_state.keyboard_state.as_mut().unwrap().xkb_context;
+                let xkb_context = &mut keyboard_state.xkb_context;
                 let xkb_state = match xkb_context.state_mut() {
                     Some(state) => state,
                     None => return,
@@ -240,7 +252,6 @@ impl Dispatch<WlKeyboard, KeyboardData, WinitState> for WinitState {
                 );
             },
             WlKeyboardEvent::RepeatInfo { rate, delay } => {
-                let keyboard_state = seat_state.keyboard_state.as_mut().unwrap();
                 keyboard_state.repeat_info = if rate == 0 {
                     // Stop the repeat once we get a disable event.
                     keyboard_state.current_repeat = None;
@@ -348,7 +359,7 @@ impl KeyboardData {
 }
 
 fn key_input(
-    seat_state: &mut WinitSeatState,
+    keyboard_state: &mut KeyboardState,
     event_sink: &mut EventSink,
     data: &KeyboardData,
     keycode: u32,
@@ -360,8 +371,6 @@ fn key_input(
         None => return,
     };
 
-    let keyboard_state = seat_state.keyboard_state.as_mut().unwrap();
-
     let device_id = crate::event::DeviceId(crate::platform_impl::DeviceId::Wayland(DeviceId));
     if let Some(mut key_context) = keyboard_state.xkb_context.key_context() {
         let event = key_context.process_key_event(keycode, state, repeat);

src/platform_impl/linux/wayland/seat/mod.rs

@@ -3,6 +3,7 @@
 use std::sync::Arc;
 
 use ahash::AHashMap;
+use tracing::warn;
 
 use sctk::reexports::client::backend::ObjectId;
 use sctk::reexports::client::protocol::wl_seat::WlSeat;
@@ -76,7 +77,13 @@ impl SeatHandler for WinitState {
         seat: WlSeat,
         capability: SeatCapability,
     ) {
-        let seat_state = self.seats.get_mut(&seat.id()).unwrap();
+        let seat_state = match self.seats.get_mut(&seat.id()) {
+            Some(seat_state) => seat_state,
+            None => {
+                warn!("Received wl_seat::new_capability for unknown seat");
+                return;
+            },
+        };
 
         match capability {
             SeatCapability::Touch if seat_state.touch.is_none() => {
@@ -89,8 +96,12 @@ impl SeatHandler for WinitState {
             },
             SeatCapability::Pointer if seat_state.pointer.is_none() => {
                 let surface = self.compositor_state.create_surface(queue_handle);
+                let viewport = self
+                    .viewporter_state
+                    .as_ref()
+                    .map(|state| state.get_viewport(&surface, queue_handle));
                 let surface_id = surface.id();
-                let pointer_data = WinitPointerData::new(seat.clone());
+                let pointer_data = WinitPointerData::new(seat.clone(), viewport);
                 let themed_pointer = self
                     .seat_state
                     .get_pointer_with_theme_and_data(
@@ -139,7 +150,13 @@ impl SeatHandler for WinitState {
         seat: WlSeat,
         capability: SeatCapability,
     ) {
-        let seat_state = self.seats.get_mut(&seat.id()).unwrap();
+        let seat_state = match self.seats.get_mut(&seat.id()) {
+            Some(seat_state) => seat_state,
+            None => {
+                warn!("Received wl_seat::remove_capability for unknown seat");
+                return;
+            },
+        };
 
         if let Some(text_input) = seat_state.text_input.take() {
             text_input.destroy();

src/platform_impl/linux/wayland/seat/pointer/mod.rs

@@ -4,6 +4,8 @@ use std::ops::Deref;
 use std::sync::{Arc, Mutex};
 use std::time::Duration;
 
+use tracing::warn;
+
 use sctk::reexports::client::delegate_dispatch;
 use sctk::reexports::client::protocol::wl_pointer::WlPointer;
 use sctk::reexports::client::protocol::wl_seat::WlSeat;
@@ -16,6 +18,7 @@ use sctk::reexports::protocols::wp::cursor_shape::v1::client::wp_cursor_shape_ma
 use sctk::reexports::protocols::wp::pointer_constraints::zv1::client::zwp_pointer_constraints_v1::{Lifetime, ZwpPointerConstraintsV1};
 use sctk::reexports::client::globals::{BindError, GlobalList};
 use sctk::reexports::csd_frame::FrameClick;
+use sctk::reexports::protocols::wp::viewporter::client::wp_viewport::WpViewport;
 
 use sctk::compositor::SurfaceData;
 use sctk::globals::GlobalData;
@@ -41,7 +44,21 @@ impl PointerHandler for WinitState {
         events: &[PointerEvent],
     ) {
         let seat = pointer.winit_data().seat();
-        let seat_state = self.seats.get(&seat.id()).unwrap();
+        let seat_state = match self.seats.get(&seat.id()) {
+            Some(seat_state) => seat_state,
+            None => {
+                warn!("Received pointer event without seat");
+                return;
+            },
+        };
+
+        let themed_pointer = match seat_state.pointer.as_ref() {
+            Some(pointer) => pointer,
+            None => {
+                warn!("Received pointer event without pointer");
+                return;
+            },
+        };
 
         let device_id = crate::event::DeviceId(crate::platform_impl::DeviceId::Wayland(DeviceId));
 
@@ -78,9 +95,7 @@ impl PointerHandler for WinitState {
                         event.position.0,
                         event.position.1,
                     ) {
-                        if let Some(pointer) = seat_state.pointer.as_ref() {
-                            let _ = pointer.set_cursor(connection, icon);
-                        }
+                        let _ = themed_pointer.set_cursor(connection, icon);
                     }
                 },
                 PointerEventKind::Leave { .. } if parent_surface != surface => {
@@ -113,9 +128,7 @@ impl PointerHandler for WinitState {
                     self.events_sink
                         .push_window_event(WindowEvent::CursorEntered { device_id }, window_id);
 
-                    if let Some(pointer) = seat_state.pointer.as_ref().map(Arc::downgrade) {
-                        window.pointer_entered(pointer);
-                    }
+                    window.pointer_entered(Arc::downgrade(themed_pointer));
 
                     // Set the currently focused surface.
                     pointer.winit_data().inner.lock().unwrap().surface = Some(window_id);
@@ -126,9 +139,7 @@ impl PointerHandler for WinitState {
                     );
                 },
                 PointerEventKind::Leave { .. } => {
-                    if let Some(pointer) = seat_state.pointer.as_ref().map(Arc::downgrade) {
-                        window.pointer_left(pointer);
-                    }
+                    window.pointer_left(Arc::downgrade(themed_pointer));
 
                     // Remove the active surface.
                     pointer.winit_data().inner.lock().unwrap().surface = None;
@@ -183,15 +194,15 @@ impl PointerHandler for WinitState {
                     pointer_data.phase = phase;
 
                     // Mice events have both pixel and discrete delta's at the same time. So prefer
-                    // the descrite values if they are present.
+                    // the discrete values if they are present.
                     let delta = if has_discrete_scroll {
-                        // XXX Wayland sign convention is the inverse of winit.
+                        // NOTE: Wayland sign convention is the inverse of winit.
                         MouseScrollDelta::LineDelta(
                             (-horizontal.discrete) as f32,
                             (-vertical.discrete) as f32,
                         )
                     } else {
-                        // XXX Wayland sign convention is the inverse of winit.
+                        // NOTE: Wayland sign convention is the inverse of winit.
                         MouseScrollDelta::PixelDelta(
                             LogicalPosition::new(-horizontal.absolute, -vertical.absolute)
                                 .to_physical(scale_factor),
@@ -215,13 +226,17 @@ pub struct WinitPointerData {
 
     /// The data required by the sctk.
     sctk_data: PointerData,
+
+    /// Viewport for fractional cursor.
+    viewport: Option<WpViewport>,
 }
 
 impl WinitPointerData {
-    pub fn new(seat: WlSeat) -> Self {
+    pub fn new(seat: WlSeat, viewport: Option<WpViewport>) -> Self {
         Self {
             inner: Mutex::new(WinitPointerDataInner::default()),
             sctk_data: PointerData::new(seat),
+            viewport,
         }
     }
 
@@ -302,6 +317,18 @@ impl WinitPointerData {
             locked_pointer.set_cursor_position_hint(surface_x, surface_y);
         }
     }
+
+    pub fn viewport(&self) -> Option<&WpViewport> {
+        self.viewport.as_ref()
+    }
+}
+
+impl Drop for WinitPointerData {
+    fn drop(&mut self) {
+        if let Some(viewport) = self.viewport.take() {
+            viewport.destroy();
+        }
+    }
 }
 
 impl PointerDataExt for WinitPointerData {

src/platform_impl/linux/wayland/seat/text_input/mod.rs

@@ -121,11 +121,15 @@ impl Dispatch<ZwpTextInputV3, TextInputData, WinitState> for TextInputState {
                     None => return,
                 };
 
-                // Clear preedit at the start of `Done`.
-                state.events_sink.push_window_event(
-                    WindowEvent::Ime(Ime::Preedit(String::new(), None)),
-                    window_id,
-                );
+                // Clear preedit, unless all we'll be doing next is sending a new preedit.
+                if text_input_data.pending_commit.is_some()
+                    || text_input_data.pending_preedit.is_none()
+                {
+                    state.events_sink.push_window_event(
+                        WindowEvent::Ime(Ime::Preedit(String::new(), None)),
+                        window_id,
+                    );
+                }
 
                 // Send `Commit`.
                 if let Some(text) = text_input_data.pending_commit.take() {

src/platform_impl/linux/wayland/seat/touch/mod.rs

@@ -1,5 +1,7 @@
 //! Touch handling.
 
+use tracing::warn;
+
 use sctk::reexports::client::protocol::wl_seat::WlSeat;
 use sctk::reexports::client::protocol::wl_surface::WlSurface;
 use sctk::reexports::client::protocol::wl_touch::WlTouch;
@@ -31,11 +33,16 @@ impl TouchHandler for WinitState {
             None => return,
         };
 
-        let location = LogicalPosition::<f64>::from(position);
-
-        let seat_state = self.seats.get_mut(&touch.seat().id()).unwrap();
+        let seat_state = match self.seats.get_mut(&touch.seat().id()) {
+            Some(seat_state) => seat_state,
+            None => {
+                warn!("Received wl_touch::down without seat");
+                return;
+            },
+        };
 
         // Update the state of the point.
+        let location = LogicalPosition::<f64>::from(position);
         seat_state.touch_map.insert(id, TouchPoint { surface, location });
 
         self.events_sink.push_window_event(
@@ -61,7 +68,13 @@ impl TouchHandler for WinitState {
         _: u32,
         id: i32,
     ) {
-        let seat_state = self.seats.get_mut(&touch.seat().id()).unwrap();
+        let seat_state = match self.seats.get_mut(&touch.seat().id()) {
+            Some(seat_state) => seat_state,
+            None => {
+                warn!("Received wl_touch::up without seat");
+                return;
+            },
+        };
 
         // Remove the touch point.
         let touch_point = match seat_state.touch_map.remove(&id) {
@@ -98,7 +111,13 @@ impl TouchHandler for WinitState {
         id: i32,
         position: (f64, f64),
     ) {
-        let seat_state = self.seats.get_mut(&touch.seat().id()).unwrap();
+        let seat_state = match self.seats.get_mut(&touch.seat().id()) {
+            Some(seat_state) => seat_state,
+            None => {
+                warn!("Received wl_touch::motion without seat");
+                return;
+            },
+        };
 
         // Remove the touch point.
         let touch_point = match seat_state.touch_map.get_mut(&id) {
@@ -129,7 +148,13 @@ impl TouchHandler for WinitState {
     }
 
     fn cancel(&mut self, _: &Connection, _: &QueueHandle<Self>, touch: &WlTouch) {
-        let seat_state = self.seats.get_mut(&touch.seat().id()).unwrap();
+        let seat_state = match self.seats.get_mut(&touch.seat().id()) {
+            Some(seat_state) => seat_state,
+            None => {
+                warn!("Received wl_touch::cancel without seat");
+                return;
+            },
+        };
 
         for (id, touch_point) in seat_state.touch_map.drain() {
             let window_id = wayland::make_wid(&touch_point.surface);

src/platform_impl/linux/wayland/state.rs

@@ -339,12 +339,30 @@ impl CompositorHandler for WinitState {
         &mut self,
         _: &Connection,
         _: &QueueHandle<Self>,
-        _: &wayland_client::protocol::wl_surface::WlSurface,
+        _: &WlSurface,
         _: wayland_client::protocol::wl_output::Transform,
     ) {
         // TODO(kchibisov) we need to expose it somehow in winit.
     }
 
+    fn surface_enter(
+        &mut self,
+        _: &Connection,
+        _: &QueueHandle<Self>,
+        _: &WlSurface,
+        _: &WlOutput,
+    ) {
+    }
+
+    fn surface_leave(
+        &mut self,
+        _: &Connection,
+        _: &QueueHandle<Self>,
+        _: &WlSurface,
+        _: &WlOutput,
+    ) {
+    }
+
     fn scale_factor_changed(
         &mut self,
         _: &Connection,

src/platform_impl/linux/wayland/types/xdg_activation.rs

@@ -80,7 +80,7 @@ impl Dispatch<XdgActivationTokenV1, XdgActivationTokenData, WinitState> for XdgA
                 state.events_sink.push_window_event(
                     crate::event::WindowEvent::ActivationTokenDone {
                         serial: *serial,
-                        token: ActivationToken::_new(token),
+                        token: ActivationToken::from_raw(token),
                     },
                     *window_id,
                 );

src/platform_impl/linux/wayland/window/mod.rs

@@ -1,5 +1,7 @@
 //! The Wayland window.
 
+use std::ffi::c_void;
+use std::ptr::NonNull;
 use std::sync::atomic::{AtomicBool, Ordering};
 use std::sync::{Arc, Mutex};
 
@@ -168,7 +170,7 @@ impl Window {
         if let (Some(xdg_activation), Some(token)) =
             (xdg_activation.as_ref(), attributes.platform_specific.activation_token)
         {
-            xdg_activation.activate(token._token, &surface);
+            xdg_activation.activate(token.token, &surface);
         }
 
         // XXX Do initial commit.
@@ -223,6 +225,10 @@ impl Window {
             window_events_sink,
         })
     }
+
+    pub(crate) fn xdg_toplevel(&self) -> Option<NonNull<c_void>> {
+        NonNull::new(self.window.xdg_toplevel().id().as_ptr().cast())
+    }
 }
 
 impl Window {

src/platform_impl/linux/wayland/window/state.rs

@@ -31,7 +31,7 @@ use sctk::subcompositor::SubcompositorState;
 use wayland_protocols_plasma::blur::client::org_kde_kwin_blur::OrgKdeKwinBlur;
 
 use crate::cursor::CustomCursor as RootCustomCursor;
-use crate::dpi::{LogicalPosition, LogicalSize, PhysicalSize, Size};
+use crate::dpi::{LogicalPosition, LogicalSize, PhysicalPosition, PhysicalSize, Size};
 use crate::error::{ExternalError, NotSupportedError};
 use crate::platform_impl::wayland::logical_to_physical_rounded;
 use crate::platform_impl::wayland::types::cursor::{CustomCursor, SelectedCursor};
@@ -222,9 +222,9 @@ impl WindowState {
     }
 
     /// Apply closure on the given pointer.
-    fn apply_on_pointer<F: Fn(&ThemedPointer<WinitPointerData>, &WinitPointerData)>(
+    fn apply_on_pointer<F: FnMut(&ThemedPointer<WinitPointerData>, &WinitPointerData)>(
         &self,
-        callback: F,
+        mut callback: F,
     ) {
         self.pointers.iter().filter_map(Weak::upgrade).for_each(|pointer| {
             let data = pointer.pointer().winit_data();
@@ -726,17 +726,26 @@ impl WindowState {
     }
 
     fn apply_custom_cursor(&self, cursor: &CustomCursor) {
-        self.apply_on_pointer(|pointer, _| {
+        self.apply_on_pointer(|pointer, data| {
             let surface = pointer.surface();
 
-            let scale = surface.data::<SurfaceData>().unwrap().surface_data().scale_factor();
+            let scale = if let Some(viewport) = data.viewport() {
+                let scale = self.scale_factor();
+                let size = PhysicalSize::new(cursor.w, cursor.h).to_logical(scale);
+                viewport.set_destination(size.width, size.height);
+                scale
+            } else {
+                let scale = surface.data::<SurfaceData>().unwrap().surface_data().scale_factor();
+                surface.set_buffer_scale(scale);
+                scale as f64
+            };
 
-            surface.set_buffer_scale(scale);
             surface.attach(Some(cursor.buffer.wl_buffer()), 0, 0);
             if surface.version() >= 4 {
                 surface.damage_buffer(0, 0, cursor.w, cursor.h);
             } else {
-                surface.damage(0, 0, cursor.w / scale, cursor.h / scale);
+                let size = PhysicalSize::new(cursor.w, cursor.h).to_logical(scale);
+                surface.damage(0, 0, size.width, size.height);
             }
             surface.commit();
 
@@ -746,12 +755,9 @@ impl WindowState {
                 .and_then(|data| data.pointer_data().latest_enter_serial())
                 .unwrap();
 
-            pointer.pointer().set_cursor(
-                serial,
-                Some(surface),
-                cursor.hotspot_x / scale,
-                cursor.hotspot_y / scale,
-            );
+            let hotspot =
+                PhysicalPosition::new(cursor.hotspot_x, cursor.hotspot_y).to_logical(scale);
+            pointer.pointer().set_cursor(serial, Some(surface), hotspot.x, hotspot.y);
         });
     }
 
@@ -827,34 +833,51 @@ impl WindowState {
             None => return Err(ExternalError::NotSupported(NotSupportedError::new())),
         };
 
-        // Replace the current mode.
-        let old_mode = std::mem::replace(&mut self.cursor_grab_mode.current_grab_mode, mode);
-
-        match old_mode {
-            CursorGrabMode::None => (),
+        let mut unset_old = false;
+        match self.cursor_grab_mode.current_grab_mode {
+            CursorGrabMode::None => unset_old = true,
             CursorGrabMode::Confined => self.apply_on_pointer(|_, data| {
                 data.unconfine_pointer();
+                unset_old = true;
             }),
             CursorGrabMode::Locked => {
-                self.apply_on_pointer(|_, data| data.unlock_pointer());
+                self.apply_on_pointer(|_, data| {
+                    data.unlock_pointer();
+                    unset_old = true;
+                });
             },
         }
 
+        // In case we haven't unset the old mode, it means that we don't have a cursor above
+        // the window, thus just wait for it to re-appear.
+        if !unset_old {
+            return Ok(());
+        }
+
+        let mut set_mode = false;
         let surface = self.window.wl_surface();
         match mode {
             CursorGrabMode::Locked => self.apply_on_pointer(|pointer, data| {
                 let pointer = pointer.pointer();
-                data.lock_pointer(pointer_constraints, surface, pointer, &self.queue_handle)
+                data.lock_pointer(pointer_constraints, surface, pointer, &self.queue_handle);
+                set_mode = true;
             }),
             CursorGrabMode::Confined => self.apply_on_pointer(|pointer, data| {
                 let pointer = pointer.pointer();
-                data.confine_pointer(pointer_constraints, surface, pointer, &self.queue_handle)
+                data.confine_pointer(pointer_constraints, surface, pointer, &self.queue_handle);
+                set_mode = true;
             }),
             CursorGrabMode::None => {
                 // Current lock/confine was already removed.
+                set_mode = true;
             },
         }
 
+        // Replace the current grab mode after we've ensure that it got updated.
+        if set_mode {
+            self.cursor_grab_mode.current_grab_mode = mode;
+        }
+
         Ok(())
     }
 

src/platform_impl/linux/x11/activation.rs

@@ -165,14 +165,14 @@ fn push_display(buffer: &mut Vec<u8>, display: &impl std::fmt::Display) {
         buffer: &'a mut Vec<u8>,
     }
 
-    impl<'a> std::fmt::Write for Writer<'a> {
+    impl std::fmt::Write for Writer<'_> {
         fn write_str(&mut self, s: &str) -> std::fmt::Result {
             self.buffer.extend_from_slice(s.as_bytes());
             Ok(())
         }
     }
 
-    write!(Writer { buffer }, "{}", display).unwrap();
+    write!(Writer { buffer }, "{display}").unwrap();
 }
 
 #[cfg(test)]

src/platform_impl/linux/x11/event_processor.rs

@@ -66,7 +66,10 @@ pub struct EventProcessor {
     pub active_window: Option<xproto::Window>,
     /// Latest modifiers we've sent for the user to trigger change in event.
     pub modifiers: Cell<ModifiersState>,
-    pub xfiltered_modifiers: VecDeque<c_ulong>,
+    // Track modifiers based on keycodes. NOTE: that serials generally don't work for tracking
+    // since they are not unique and could be duplicated in case of sequence of key events is
+    // delivered at near the same time.
+    pub xfiltered_modifiers: VecDeque<u8>,
     pub xmodmap: util::ModifierKeymap,
     pub is_composing: bool,
 }
@@ -129,6 +132,7 @@ impl EventProcessor {
     /// Specifically, this involves all of the KeyPress events in compose/pre-edit sequences,
     /// along with an extra copy of the KeyRelease events. This also prevents backspace and
     /// arrow keys from being detected twice.
+    #[must_use]
     fn filter_event(&mut self, xev: &mut XEvent) -> bool {
         let wt = Self::window_target(&self.target);
         unsafe {
@@ -145,20 +149,38 @@ impl EventProcessor {
     {
         let event_type = xev.get_type();
 
-        if self.filter_event(xev) {
-            if event_type == xlib::KeyPress || event_type == xlib::KeyRelease {
+        // If we have IME disabled, don't try to `filter_event`, since only IME can consume them
+        // and forward back. This is not desired for e.g. games since some IMEs may delay the input
+        // and game can toggle IME back when e.g. typing into some field where latency won't really
+        // matter.
+        let filtered = if event_type == xlib::KeyPress || event_type == xlib::KeyRelease {
+            let wt = Self::window_target(&self.target);
+            let ime = wt.ime.as_ref();
+            let window = self.active_window.map(|window| window as XWindow);
+            let forward_to_ime = ime
+                .and_then(|ime| window.map(|window| ime.borrow().is_ime_allowed(window)))
+                .unwrap_or(false);
+
+            let filtered = forward_to_ime && self.filter_event(xev);
+            if filtered {
                 let xev: &XKeyEvent = xev.as_ref();
                 if self.xmodmap.is_modifier(xev.keycode as u8) {
                     // Don't grow the buffer past the `MAX_MOD_REPLAY_LEN`. This could happen
-                    // when the modifiers are consumed entirely or serials are altered.
-                    //
-                    // Both cases shouldn't happen in well behaving clients.
+                    // when the modifiers are consumed entirely.
                     if self.xfiltered_modifiers.len() == MAX_MOD_REPLAY_LEN {
                         self.xfiltered_modifiers.pop_back();
                     }
-                    self.xfiltered_modifiers.push_front(xev.serial);
+                    self.xfiltered_modifiers.push_front(xev.keycode as u8);
                 }
             }
+
+            filtered
+        } else {
+            self.filter_event(xev)
+        };
+
+        // Don't process event if it was filtered.
+        if filtered {
             return;
         }
 
@@ -434,7 +456,7 @@ impl EventProcessor {
             let flags = xev.data.get_long(1);
             let version = flags >> 24;
             self.dnd.version = Some(version);
-            let has_more_types = flags - (flags & (c_long::max_value() - 1)) == 1;
+            let has_more_types = flags - (flags & (c_long::MAX - 1)) == 1;
             if !has_more_types {
                 let type_list = vec![
                     xev.data.get_long(2) as xproto::Atom,
@@ -929,7 +951,7 @@ impl EventProcessor {
         // itself are out of sync due to XkbState being delivered before XKeyEvent, since it's
         // being replayed by the XIM, thus we should replay ourselves.
         let replay = if let Some(position) =
-            self.xfiltered_modifiers.iter().rev().position(|&s| s == xev.serial)
+            self.xfiltered_modifiers.iter().rev().position(|&s| s == xev.keycode as u8)
         {
             // We don't have to replay modifiers pressed before the current event if some events
             // were not forwarded to us, since their state is irrelevant.

src/platform_impl/linux/x11/ime/callbacks.rs

@@ -123,19 +123,15 @@ unsafe fn replace_im(inner: *mut ImeInner) -> Result<(), ReplaceImError> {
         let is_allowed =
             old_context.as_ref().map(|old_context| old_context.is_allowed()).unwrap_or_default();
 
-        // We can't use the style from the old context here, since it may change on reload, so
-        // pick style from the new XIM based on the old state.
-        let style = if is_allowed { new_im.preedit_style } else { new_im.none_style };
-
         let new_context = {
             let result = unsafe {
                 ImeContext::new(
                     xconn,
-                    new_im.im,
-                    style,
+                    &new_im,
                     *window,
                     spot,
                     (*inner).event_sender.clone(),
+                    is_allowed,
                 )
             };
             if result.is_err() {

src/platform_impl/linux/x11/ime/context.rs

@@ -5,10 +5,9 @@ use std::{mem, ptr};
 
 use x11_dl::xlib::{XIMCallback, XIMPreeditCaretCallbackStruct, XIMPreeditDrawCallbackStruct};
 
-use crate::platform_impl::platform::x11::ime::input_method::{Style, XIMStyle};
-use crate::platform_impl::platform::x11::ime::{ImeEvent, ImeEventSender};
-
 use super::{ffi, util, XConnection, XError};
+use crate::platform_impl::platform::x11::ime::input_method::{InputMethod, Style, XIMStyle};
+use crate::platform_impl::platform::x11::ime::{ImeEvent, ImeEventSender};
 
 /// IME creation error.
 #[derive(Debug)]
@@ -158,7 +157,9 @@ struct PreeditCallbacks {
 impl PreeditCallbacks {
     pub fn new(client_data: ffi::XPointer) -> PreeditCallbacks {
         let start_callback = create_xim_callback(client_data, unsafe {
-            mem::transmute(preedit_start_callback as usize)
+            mem::transmute::<usize, unsafe extern "C" fn(ffi::XIM, ffi::XPointer, ffi::XPointer)>(
+                preedit_start_callback as usize,
+            )
         });
         let done_callback = create_xim_callback(client_data, preedit_done_callback);
         let caret_callback = create_xim_callback(client_data, preedit_caret_callback);
@@ -182,7 +183,7 @@ struct ImeContextClientData {
 pub struct ImeContext {
     pub(crate) ic: ffi::XIC,
     pub(crate) ic_spot: ffi::XPoint,
-    pub(crate) style: Style,
+    pub(crate) allowed: bool,
     // Since the data is passed shared between X11 XIM callbacks, but couldn't be directly free
     // from there we keep the pointer to automatically deallocate it.
     _client_data: Box<ImeContextClientData>,
@@ -191,11 +192,11 @@ pub struct ImeContext {
 impl ImeContext {
     pub(crate) unsafe fn new(
         xconn: &Arc<XConnection>,
-        im: ffi::XIM,
-        style: Style,
+        im: &InputMethod,
         window: ffi::Window,
         ic_spot: Option<ffi::XPoint>,
         event_sender: ImeEventSender,
+        allowed: bool,
     ) -> Result<Self, ImeContextCreationError> {
         let client_data = Box::into_raw(Box::new(ImeContextClientData {
             window,
@@ -204,20 +205,24 @@ impl ImeContext {
             cursor_pos: 0,
         }));
 
+        let style = if allowed { im.preedit_style } else { im.none_style };
+
         let ic = match style as _ {
             Style::Preedit(style) => unsafe {
                 ImeContext::create_preedit_ic(
                     xconn,
-                    im,
+                    im.im,
                     style,
                     window,
                     client_data as ffi::XPointer,
                 )
             },
             Style::Nothing(style) => unsafe {
-                ImeContext::create_nothing_ic(xconn, im, style, window)
+                ImeContext::create_nothing_ic(xconn, im.im, style, window)
+            },
+            Style::None(style) => unsafe {
+                ImeContext::create_none_ic(xconn, im.im, style, window)
             },
-            Style::None(style) => unsafe { ImeContext::create_none_ic(xconn, im, style, window) },
         }
         .ok_or(ImeContextCreationError::Null)?;
 
@@ -226,7 +231,7 @@ impl ImeContext {
         let mut context = ImeContext {
             ic,
             ic_spot: ffi::XPoint { x: 0, y: 0 },
-            style,
+            allowed,
             _client_data: unsafe { Box::from_raw(client_data) },
         };
 
@@ -333,7 +338,7 @@ impl ImeContext {
     }
 
     pub fn is_allowed(&self) -> bool {
-        !matches!(self.style, Style::None(_))
+        self.allowed
     }
 
     // Set the spot for preedit text. Setting spot isn't working with libX11 when preedit callbacks

src/platform_impl/linux/x11/ime/input_method.rs

@@ -176,7 +176,7 @@ unsafe fn get_xim_servers(xconn: &Arc<XConnection>) -> Result<Vec<String>, GetXi
         )
         .map_err(GetXimServersError::GetPropertyError)?
         .into_iter()
-        .map(ffi::Atom::from)
+        .map(|atom| atom as _)
         .collect::<Vec<_>>();
 
     let mut names: Vec<*const c_char> = Vec::with_capacity(atoms.len());

src/platform_impl/linux/x11/ime/mod.rs

@@ -10,15 +10,13 @@ use std::sync::Arc;
 
 #[cfg(feature = "serde")]
 use serde::{Deserialize, Serialize};
-use tracing::debug;
-
-use super::{ffi, util, XConnection, XError};
 
 use self::callbacks::*;
 use self::context::ImeContext;
 pub use self::context::ImeContextCreationError;
 use self::inner::{close_im, ImeInner};
-use self::input_method::{PotentialInputMethods, Style};
+use self::input_method::PotentialInputMethods;
+use super::{ffi, util, XConnection, XError};
 
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
@@ -114,39 +112,26 @@ impl Ime {
     pub fn create_context(
         &mut self,
         window: ffi::Window,
-        with_preedit: bool,
+        with_ime: bool,
     ) -> Result<bool, ImeContextCreationError> {
         let context = if self.is_destroyed() {
             // Create empty entry in map, so that when IME is rebuilt, this window has a context.
             None
         } else {
             let im = self.inner.im.as_ref().unwrap();
-            let style = if with_preedit { im.preedit_style } else { im.none_style };
 
             let context = unsafe {
                 ImeContext::new(
                     &self.inner.xconn,
-                    im.im,
-                    style,
+                    im,
                     window,
                     None,
                     self.inner.event_sender.clone(),
+                    with_ime,
                 )?
             };
 
-            // Check the state on the context, since it could fail to enable or disable preedit.
-            let event = if matches!(style, Style::None(_)) {
-                if with_preedit {
-                    debug!("failed to create IME context with preedit support.")
-                }
-                ImeEvent::Disabled
-            } else {
-                if !with_preedit {
-                    debug!("failed to create IME context without preedit support.")
-                }
-                ImeEvent::Enabled
-            };
-
+            let event = if context.is_allowed() { ImeEvent::Enabled } else { ImeEvent::Disabled };
             self.inner.event_sender.send((window, event)).expect("Failed to send enabled event");
 
             Some(context)
@@ -226,6 +211,16 @@ impl Ime {
         // Create new context supporting IME input.
         let _ = self.create_context(window, allowed);
     }
+
+    pub fn is_ime_allowed(&self, window: ffi::Window) -> bool {
+        if self.is_destroyed() {
+            false
+        } else if let Some(Some(context)) = self.inner.contexts.get(&window) {
+            context.is_allowed()
+        } else {
+            false
+        }
+    }
 }
 
 impl Drop for Ime {

src/platform_impl/linux/x11/mod.rs

@@ -1,5 +1,3 @@
-#![cfg(x11_platform)]
-
 use std::cell::{Cell, RefCell};
 use std::collections::{HashMap, HashSet, VecDeque};
 use std::ffi::CStr;
@@ -27,7 +25,6 @@ use x11rb::protocol::xproto::{self, ConnectionExt as _};
 use x11rb::x11_utils::X11Error as LogicalError;
 use x11rb::xcb_ffi::ReplyOrIdError;
 
-use crate::application::ApplicationHandler;
 use crate::error::{EventLoopError, OsError as RootOsError};
 use crate::event::{Event, StartCause, WindowEvent};
 use crate::event_loop::{ActiveEventLoop as RootAEL, ControlFlow, DeviceEvents, EventLoopClosed};
@@ -380,16 +377,12 @@ impl<T: 'static> EventLoop<T> {
         &self.event_processor.target
     }
 
-    pub fn run_app<A: ApplicationHandler<T>>(mut self, app: &mut A) -> Result<(), EventLoopError> {
-        self.run_app_on_demand(app)
-    }
-
-    pub fn run_app_on_demand<A: ApplicationHandler<T>>(
-        &mut self,
-        app: &mut A,
-    ) -> Result<(), EventLoopError> {
+    pub fn run_on_demand<F>(&mut self, mut event_handler: F) -> Result<(), EventLoopError>
+    where
+        F: FnMut(Event<T>, &RootAEL),
+    {
         let exit = loop {
-            match self.pump_app_events(None, app) {
+            match self.pump_events(None, &mut event_handler) {
                 PumpStatus::Exit(0) => {
                     break Ok(());
                 },
@@ -414,27 +407,26 @@ impl<T: 'static> EventLoop<T> {
         exit
     }
 
-    pub fn pump_app_events<A: ApplicationHandler<T>>(
-        &mut self,
-        timeout: Option<Duration>,
-        app: &mut A,
-    ) -> PumpStatus {
+    pub fn pump_events<F>(&mut self, timeout: Option<Duration>, mut callback: F) -> PumpStatus
+    where
+        F: FnMut(Event<T>, &RootAEL),
+    {
         if !self.loop_running {
             self.loop_running = true;
 
             // run the initial loop iteration
-            self.single_iteration(app, StartCause::Init);
+            self.single_iteration(&mut callback, StartCause::Init);
         }
 
         // Consider the possibility that the `StartCause::Init` iteration could
         // request to Exit.
         if !self.exiting() {
-            self.poll_events_with_timeout(timeout, app);
+            self.poll_events_with_timeout(timeout, &mut callback);
         }
         if let Some(code) = self.exit_code() {
             self.loop_running = false;
 
-            app.exiting(self.window_target());
+            callback(Event::LoopExiting, self.window_target());
 
             PumpStatus::Exit(code)
         } else {
@@ -448,11 +440,10 @@ impl<T: 'static> EventLoop<T> {
             || self.redraw_receiver.has_incoming()
     }
 
-    pub fn poll_events_with_timeout<A: ApplicationHandler<T>>(
-        &mut self,
-        mut timeout: Option<Duration>,
-        app: &mut A,
-    ) {
+    pub fn poll_events_with_timeout<F>(&mut self, mut timeout: Option<Duration>, mut callback: F)
+    where
+        F: FnMut(Event<T>, &RootAEL),
+    {
         let start = Instant::now();
 
         let has_pending = self.has_pending();
@@ -506,24 +497,28 @@ impl<T: 'static> EventLoop<T> {
         // If we don't have any pending `_receiver`
         if !self.has_pending()
             && !matches!(&cause, StartCause::ResumeTimeReached { .. } | StartCause::Poll)
+            && timeout.is_none()
         {
             return;
         }
 
-        self.single_iteration(app, cause);
+        self.single_iteration(&mut callback, cause);
     }
 
-    fn single_iteration<A: ApplicationHandler<T>>(&mut self, app: &mut A, cause: StartCause) {
-        app.new_events(&self.event_processor.target, cause);
+    fn single_iteration<F>(&mut self, callback: &mut F, cause: StartCause)
+    where
+        F: FnMut(Event<T>, &RootAEL),
+    {
+        callback(Event::NewEvents(cause), &self.event_processor.target);
 
         // NB: For consistency all platforms must emit a 'resumed' event even though X11
         // applications don't themselves have a formal suspend/resume lifecycle.
         if cause == StartCause::Init {
-            app.resumed(&self.event_processor.target)
+            callback(Event::Resumed, &self.event_processor.target);
         }
 
         // Process all pending events
-        self.drain_events(app);
+        self.drain_events(callback);
 
         // Empty activation tokens.
         while let Ok((window_id, serial)) = self.activation_receiver.try_recv() {
@@ -533,12 +528,14 @@ impl<T: 'static> EventLoop<T> {
 
             match token {
                 Some(Ok(token)) => {
-                    let window_id = crate::window::WindowId(window_id);
-                    let event = WindowEvent::ActivationTokenDone {
-                        serial,
-                        token: crate::window::ActivationToken::_new(token),
+                    let event = Event::WindowEvent {
+                        window_id: crate::window::WindowId(window_id),
+                        event: WindowEvent::ActivationTokenDone {
+                            serial,
+                            token: crate::window::ActivationToken::from_raw(token),
+                        },
                     };
-                    app.window_event(&self.event_processor.target, window_id, event);
+                    callback(event, &self.event_processor.target)
                 },
                 Some(Err(e)) => {
                     tracing::error!("Failed to get activation token: {}", e);
@@ -550,7 +547,7 @@ impl<T: 'static> EventLoop<T> {
         // Empty the user event buffer
         {
             while let Ok(event) = self.user_receiver.try_recv() {
-                app.user_event(&self.event_processor.target, event);
+                callback(Event::UserEvent(event), &self.event_processor.target);
             }
         }
 
@@ -564,24 +561,28 @@ impl<T: 'static> EventLoop<T> {
 
             for window_id in windows {
                 let window_id = crate::window::WindowId(window_id);
-                app.window_event(
+                callback(
+                    Event::WindowEvent { window_id, event: WindowEvent::RedrawRequested },
                     &self.event_processor.target,
-                    window_id,
-                    WindowEvent::RedrawRequested,
                 );
             }
         }
 
         // This is always the last event we dispatch before poll again
-        app.about_to_wait(&self.event_processor.target);
+        {
+            callback(Event::AboutToWait, &self.event_processor.target);
+        }
     }
 
-    fn drain_events<A: ApplicationHandler<T>>(&mut self, app: &mut A) {
+    fn drain_events<F>(&mut self, callback: &mut F)
+    where
+        F: FnMut(Event<T>, &RootAEL),
+    {
         let mut xev = MaybeUninit::uninit();
 
         while unsafe { self.event_processor.poll_one_event(xev.as_mut_ptr()) } {
             let mut xev = unsafe { xev.assume_init() };
-            self.event_processor.process_event(&mut xev, |window_target, event: Event<T>| {
+            self.event_processor.process_event(&mut xev, |window_target, event| {
                 if let Event::WindowEvent {
                     window_id: crate::window::WindowId(wid),
                     event: WindowEvent::RedrawRequested,
@@ -590,15 +591,7 @@ impl<T: 'static> EventLoop<T> {
                     let window_target = EventProcessor::window_target(window_target);
                     window_target.redraw_sender.send(wid).unwrap();
                 } else {
-                    match event {
-                        Event::WindowEvent { window_id, event } => {
-                            app.window_event(window_target, window_id, event)
-                        },
-                        Event::DeviceEvent { device_id, event } => {
-                            app.device_event(window_target, device_id, event)
-                        },
-                        _ => unreachable!("event which is neither device nor window event."),
-                    }
+                    callback(event, window_target);
                 }
             });
         }
@@ -759,14 +752,14 @@ impl<'a> DeviceInfo<'a> {
     }
 }
 
-impl<'a> Drop for DeviceInfo<'a> {
+impl Drop for DeviceInfo<'_> {
     fn drop(&mut self) {
         assert!(!self.info.is_null());
         unsafe { (self.xconn.xinput2.XIFreeDeviceInfo)(self.info as *mut _) };
     }
 }
 
-impl<'a> Deref for DeviceInfo<'a> {
+impl Deref for DeviceInfo<'_> {
     type Target = [ffi::XIDeviceInfo];
 
     fn deref(&self) -> &Self::Target {
@@ -779,7 +772,7 @@ pub struct DeviceId(xinput::DeviceId);
 
 impl DeviceId {
     #[allow(unused)]
-    pub const unsafe fn dummy() -> Self {
+    pub const fn dummy() -> Self {
         DeviceId(0)
     }
 }
@@ -857,24 +850,24 @@ pub enum X11Error {
 impl fmt::Display for X11Error {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self {
-            X11Error::Xlib(e) => write!(f, "Xlib error: {}", e),
-            X11Error::Connect(e) => write!(f, "X11 connection error: {}", e),
-            X11Error::Connection(e) => write!(f, "X11 connection error: {}", e),
-            X11Error::XidsExhausted(e) => write!(f, "XID range exhausted: {}", e),
-            X11Error::GetProperty(e) => write!(f, "Failed to get X property {}", e),
-            X11Error::X11(e) => write!(f, "X11 error: {:?}", e),
-            X11Error::UnexpectedNull(s) => write!(f, "Xlib function returned null: {}", s),
+            X11Error::Xlib(e) => write!(f, "Xlib error: {e}"),
+            X11Error::Connect(e) => write!(f, "X11 connection error: {e}"),
+            X11Error::Connection(e) => write!(f, "X11 connection error: {e}"),
+            X11Error::XidsExhausted(e) => write!(f, "XID range exhausted: {e}"),
+            X11Error::GetProperty(e) => write!(f, "Failed to get X property {e}"),
+            X11Error::X11(e) => write!(f, "X11 error: {e:?}"),
+            X11Error::UnexpectedNull(s) => write!(f, "Xlib function returned null: {s}"),
             X11Error::InvalidActivationToken(s) => write!(
                 f,
                 "Invalid activation token: {}",
                 std::str::from_utf8(s).unwrap_or("<invalid utf8>")
             ),
-            X11Error::MissingExtension(s) => write!(f, "Missing X11 extension: {}", s),
+            X11Error::MissingExtension(s) => write!(f, "Missing X11 extension: {s}"),
             X11Error::NoSuchVisual(visualid) => {
-                write!(f, "Could not find a matching X11 visual for ID `{:x}`", visualid)
+                write!(f, "Could not find a matching X11 visual for ID `{visualid:x}`")
             },
             X11Error::XsettingsParse(err) => {
-                write!(f, "Failed to parse xsettings: {:?}", err)
+                write!(f, "Failed to parse xsettings: {err:?}")
             },
         }
     }
@@ -965,7 +958,7 @@ trait CookieResultExt {
     fn expect_then_ignore_error(self, msg: &str);
 }
 
-impl<'a, E: fmt::Debug> CookieResultExt for Result<VoidCookie<'a>, E> {
+impl<E: fmt::Debug> CookieResultExt for Result<VoidCookie<'_>, E> {
     fn expect_then_ignore_error(self, msg: &str) {
         self.expect(msg).ignore_error()
     }

src/platform_impl/linux/x11/monitor.rs

@@ -301,7 +301,7 @@ impl XConnection {
         let info = self
             .xcb_connection()
             .extension_information(randr::X11_EXTENSION_NAME)?
-            .ok_or_else(|| X11Error::MissingExtension(randr::X11_EXTENSION_NAME))?;
+            .ok_or(X11Error::MissingExtension(randr::X11_EXTENSION_NAME))?;
 
         // Select input data.
         let event_mask =

src/platform_impl/linux/x11/util/memory.rs

@@ -19,7 +19,7 @@ impl<'a, T> XSmartPointer<'a, T> {
     }
 }
 
-impl<'a, T> Deref for XSmartPointer<'a, T> {
+impl<T> Deref for XSmartPointer<'_, T> {
     type Target = T;
 
     fn deref(&self) -> &T {
@@ -27,13 +27,13 @@ impl<'a, T> Deref for XSmartPointer<'a, T> {
     }
 }
 
-impl<'a, T> DerefMut for XSmartPointer<'a, T> {
+impl<T> DerefMut for XSmartPointer<'_, T> {
     fn deref_mut(&mut self) -> &mut T {
         unsafe { &mut *self.ptr }
     }
 }
 
-impl<'a, T> Drop for XSmartPointer<'a, T> {
+impl<T> Drop for XSmartPointer<'_, T> {
     fn drop(&mut self) {
         unsafe {
             (self.xconn.xlib.XFree)(self.ptr as *mut _);

src/platform_impl/linux/x11/util/mod.rs

@@ -51,7 +51,7 @@ where
 }
 
 impl XConnection {
-    // This is impoartant, so pay attention!
+    // This is important, so pay attention!
     // Xlib has an output buffer, and tries to hide the async nature of X from you.
     // This buffer contains the requests you make, and is flushed under various circumstances:
     // 1. `XPending`, `XNextEvent`, and `XWindowEvent` flush "as needed"

src/platform_impl/linux/x11/util/randr.rs

@@ -79,7 +79,7 @@ impl XConnection {
             .iter()
             // XRROutputInfo contains an array of mode ids that correspond to
             // modes in the array in XRRScreenResources
-            .filter(|x| output_modes.iter().any(|id| x.id == *id))
+            .filter(|x| output_modes.contains(&x.id))
             .map(|mode| {
                 VideoModeHandle {
                     size: (mode.width.into(), mode.height.into()),

src/platform_impl/linux/x11/window.rs

@@ -144,12 +144,26 @@ impl UnownedWindow {
     ) -> Result<UnownedWindow, RootOsError> {
         let xconn = &event_loop.xconn;
         let atoms = xconn.atoms();
+
+        let screen_id = match window_attrs.platform_specific.x11.screen_id {
+            Some(id) => id,
+            None => xconn.default_screen_index() as c_int,
+        };
+
+        let screen = {
+            let screen_id_usize = usize::try_from(screen_id)
+                .map_err(|_| os_error!(OsError::Misc("screen id must be non-negative")))?;
+            xconn.xcb_connection().setup().roots.get(screen_id_usize).ok_or(os_error!(
+                OsError::Misc("requested screen id not present in server's response")
+            ))?
+        };
+
         #[cfg(feature = "rwh_06")]
         let root = match window_attrs.parent_window.as_ref().map(|handle| handle.0) {
             Some(rwh_06::RawWindowHandle::Xlib(handle)) => handle.window as xproto::Window,
             Some(rwh_06::RawWindowHandle::Xcb(handle)) => handle.window.get(),
             Some(raw) => unreachable!("Invalid raw window handle {raw:?} on X11"),
-            None => event_loop.root,
+            None => screen.root,
         };
         #[cfg(not(feature = "rwh_06"))]
         let root = event_loop.root;
@@ -207,18 +221,10 @@ impl UnownedWindow {
             dimensions
         };
 
-        let screen_id = match window_attrs.platform_specific.x11.screen_id {
-            Some(id) => id,
-            None => xconn.default_screen_index() as c_int,
-        };
-
-        // An iterator over all of the visuals combined with their depths.
-        let mut all_visuals = xconn
-            .xcb_connection()
-            .setup()
-            .roots
+        // An iterator over the visuals matching screen id combined with their depths.
+        let mut all_visuals = screen
+            .allowed_depths
             .iter()
-            .flat_map(|root| &root.allowed_depths)
             .flat_map(|depth| depth.visuals.iter().map(move |visual| (visual, depth.depth)));
 
         // creating
@@ -484,6 +490,20 @@ impl UnownedWindow {
             );
             leap!(result).ignore_error();
 
+            // Select XInput2 events
+            let mask = xinput::XIEventMask::MOTION
+                | xinput::XIEventMask::BUTTON_PRESS
+                | xinput::XIEventMask::BUTTON_RELEASE
+                | xinput::XIEventMask::ENTER
+                | xinput::XIEventMask::LEAVE
+                | xinput::XIEventMask::FOCUS_IN
+                | xinput::XIEventMask::FOCUS_OUT
+                | xinput::XIEventMask::TOUCH_BEGIN
+                | xinput::XIEventMask::TOUCH_UPDATE
+                | xinput::XIEventMask::TOUCH_END;
+            leap!(xconn.select_xinput_events(window.xwindow, super::ALL_MASTER_DEVICES, mask))
+                .ignore_error();
+
             // Set visibility (map window)
             if window_attrs.visible {
                 leap!(xconn.xcb_connection().map_window(window.xwindow)).ignore_error();
@@ -507,20 +527,6 @@ impl UnownedWindow {
                 }
             }
 
-            // Select XInput2 events
-            let mask = xinput::XIEventMask::MOTION
-                | xinput::XIEventMask::BUTTON_PRESS
-                | xinput::XIEventMask::BUTTON_RELEASE
-                | xinput::XIEventMask::ENTER
-                | xinput::XIEventMask::LEAVE
-                | xinput::XIEventMask::FOCUS_IN
-                | xinput::XIEventMask::FOCUS_OUT
-                | xinput::XIEventMask::TOUCH_BEGIN
-                | xinput::XIEventMask::TOUCH_UPDATE
-                | xinput::XIEventMask::TOUCH_END;
-            leap!(xconn.select_xinput_events(window.xwindow, super::ALL_MASTER_DEVICES, mask))
-                .ignore_error();
-
             // Try to create input context for the window.
             if let Some(ime) = event_loop.ime.as_ref() {
                 let result = ime.borrow_mut().create_context(window.xwindow as ffi::Window, false);
@@ -553,7 +559,7 @@ impl UnownedWindow {
 
         // Remove the startup notification if we have one.
         if let Some(startup) = window_attrs.platform_specific.activation_token.as_ref() {
-            leap!(xconn.remove_activation_token(xwindow, &startup._token));
+            leap!(xconn.remove_activation_token(xwindow, &startup.token));
         }
 
         // We never want to give the user a broken window, since by then, it's too late to handle.
@@ -970,8 +976,8 @@ impl UnownedWindow {
         let vert_atom = atoms[_NET_WM_STATE_MAXIMIZED_VERT];
         match state {
             Ok(atoms) => {
-                let horz_maximized = atoms.iter().any(|atom: &xproto::Atom| *atom == horz_atom);
-                let vert_maximized = atoms.iter().any(|atom: &xproto::Atom| *atom == vert_atom);
+                let horz_maximized = atoms.contains(&horz_atom);
+                let vert_maximized = atoms.contains(&vert_atom);
                 horz_maximized && vert_maximized
             },
             _ => false,
@@ -1486,6 +1492,11 @@ impl UnownedWindow {
 
     #[inline]
     pub fn set_cursor_grab(&self, mode: CursorGrabMode) -> Result<(), ExternalError> {
+        // We don't support the locked cursor yet, so ignore it early on.
+        if mode == CursorGrabMode::Locked {
+            return Err(ExternalError::NotSupported(NotSupportedError::new()));
+        }
+
         let mut grabbed_lock = self.cursor_grabbed_mode.lock().unwrap();
         if mode == *grabbed_lock {
             return Ok(());
@@ -1497,40 +1508,40 @@ impl UnownedWindow {
             .xcb_connection()
             .ungrab_pointer(x11rb::CURRENT_TIME)
             .expect_then_ignore_error("Failed to call `xcb_ungrab_pointer`");
+        *grabbed_lock = CursorGrabMode::None;
 
         let result = match mode {
             CursorGrabMode::None => self.xconn.flush_requests().map_err(|err| {
                 ExternalError::Os(os_error!(OsError::XError(X11Error::Xlib(err).into())))
             }),
             CursorGrabMode::Confined => {
-                let result = {
-                    self.xconn
-                        .xcb_connection()
-                        .grab_pointer(
-                            true as _,
-                            self.xwindow,
-                            xproto::EventMask::BUTTON_PRESS
-                                | xproto::EventMask::BUTTON_RELEASE
-                                | xproto::EventMask::ENTER_WINDOW
-                                | xproto::EventMask::LEAVE_WINDOW
-                                | xproto::EventMask::POINTER_MOTION
-                                | xproto::EventMask::POINTER_MOTION_HINT
-                                | xproto::EventMask::BUTTON1_MOTION
-                                | xproto::EventMask::BUTTON2_MOTION
-                                | xproto::EventMask::BUTTON3_MOTION
-                                | xproto::EventMask::BUTTON4_MOTION
-                                | xproto::EventMask::BUTTON5_MOTION
-                                | xproto::EventMask::KEYMAP_STATE,
-                            xproto::GrabMode::ASYNC,
-                            xproto::GrabMode::ASYNC,
-                            self.xwindow,
-                            0u32,
-                            x11rb::CURRENT_TIME,
-                        )
-                        .expect("Failed to call `grab_pointer`")
-                        .reply()
-                        .expect("Failed to receive reply from `grab_pointer`")
-                };
+                let result = self
+                    .xconn
+                    .xcb_connection()
+                    .grab_pointer(
+                        true as _,
+                        self.xwindow,
+                        xproto::EventMask::BUTTON_PRESS
+                            | xproto::EventMask::BUTTON_RELEASE
+                            | xproto::EventMask::ENTER_WINDOW
+                            | xproto::EventMask::LEAVE_WINDOW
+                            | xproto::EventMask::POINTER_MOTION
+                            | xproto::EventMask::POINTER_MOTION_HINT
+                            | xproto::EventMask::BUTTON1_MOTION
+                            | xproto::EventMask::BUTTON2_MOTION
+                            | xproto::EventMask::BUTTON3_MOTION
+                            | xproto::EventMask::BUTTON4_MOTION
+                            | xproto::EventMask::BUTTON5_MOTION
+                            | xproto::EventMask::KEYMAP_STATE,
+                        xproto::GrabMode::ASYNC,
+                        xproto::GrabMode::ASYNC,
+                        self.xwindow,
+                        0u32,
+                        x11rb::CURRENT_TIME,
+                    )
+                    .expect("Failed to call `grab_pointer`")
+                    .reply()
+                    .expect("Failed to receive reply from `grab_pointer`");
 
                 match result.status {
                     xproto::GrabStatus::SUCCESS => Ok(()),
@@ -1550,9 +1561,7 @@ impl UnownedWindow {
                 }
                 .map_err(|err| ExternalError::Os(os_error!(OsError::Misc(err))))
             },
-            CursorGrabMode::Locked => {
-                return Err(ExternalError::NotSupported(NotSupportedError::new()));
-            },
+            CursorGrabMode::Locked => return Ok(()),
         };
 
         if result.is_ok() {

src/platform_impl/linux/x11/xdisplay.rs

@@ -145,7 +145,7 @@ impl XConnection {
     fn new_xsettings_screen(xcb: &XCBConnection, default_screen: usize) -> Option<xproto::Atom> {
         // Fetch the _XSETTINGS_S[screen number] atom.
         let xsettings_screen = xcb
-            .intern_atom(false, format!("_XSETTINGS_S{}", default_screen).as_bytes())
+            .intern_atom(false, format!("_XSETTINGS_S{default_screen}").as_bytes())
             .ok()?
             .reply()
             .ok()?

src/platform_impl/macos/app.rs

@@ -1,49 +1,104 @@
 #![allow(clippy::unnecessary_cast)]
+#![allow(unknown_lints)] // New lint below
+#![allow(static_mut_refs)] // Uses `MainThreadBound` in new version.
 
-use objc2::{declare_class, msg_send, mutability, ClassType, DeclaredClass};
-use objc2_app_kit::{NSApplication, NSEvent, NSEventModifierFlags, NSEventType, NSResponder};
-use objc2_foundation::{MainThreadMarker, NSObject};
+use std::cell::Cell;
+use std::mem;
 
-use super::app_delegate::ApplicationDelegate;
+use objc2::runtime::{Imp, Sel};
+use objc2::sel;
+use objc2_app_kit::{NSApplication, NSEvent, NSEventModifierFlags, NSEventType};
+use objc2_foundation::MainThreadMarker;
+
+use super::app_state::ApplicationDelegate;
 use crate::event::{DeviceEvent, ElementState};
 
-declare_class!(
-    pub(super) struct WinitApplication;
+type SendEvent = extern "C" fn(&NSApplication, Sel, &NSEvent);
 
-    unsafe impl ClassType for WinitApplication {
-        #[inherits(NSResponder, NSObject)]
-        type Super = NSApplication;
-        type Mutability = mutability::MainThreadOnly;
-        const NAME: &'static str = "WinitApplication";
-    }
+// NOTE: Only used on the main thread. Ideally, we'd use `MainThreadBound`, but that isn't
+// constructible from `const` with this `objc2` version.
+static mut ORIGINAL: Cell<Option<SendEvent>> = Cell::new(None);
 
-    impl DeclaredClass for WinitApplication {}
+extern "C" fn send_event(app: &NSApplication, sel: Sel, event: &NSEvent) {
+    let mtm = MainThreadMarker::from(app);
 
-    unsafe impl WinitApplication {
-        // Normally, holding Cmd + any key never sends us a `keyUp` event for that key.
-        // Overriding `sendEvent:` like this fixes that. (https://stackoverflow.com/a/15294196)
-        // Fun fact: Firefox still has this bug! (https://bugzilla.mozilla.org/show_bug.cgi?id=1299553)
-        #[method(sendEvent:)]
-        fn send_event(&self, event: &NSEvent) {
-            // For posterity, there are some undocumented event types
-            // (https://github.com/servo/cocoa-rs/issues/155)
-            // but that doesn't really matter here.
-            let event_type = unsafe { event.r#type() };
-            let modifier_flags = unsafe { event.modifierFlags() };
-            if event_type == NSEventType::KeyUp
-                && modifier_flags.contains(NSEventModifierFlags::NSEventModifierFlagCommand)
-            {
-                if let Some(key_window) = self.keyWindow() {
-                    key_window.sendEvent(event);
-                }
-            } else {
-                let delegate = ApplicationDelegate::get(MainThreadMarker::from(self));
-                maybe_dispatch_device_event(&delegate, event);
-                unsafe { msg_send![super(self), sendEvent: event] }
-            }
+    // Normally, holding Cmd + any key never sends us a `keyUp` event for that key.
+    // Overriding `sendEvent:` fixes that. (https://stackoverflow.com/a/15294196)
+    // Fun fact: Firefox still has this bug! (https://bugzilla.mozilla.org/show_bug.cgi?id=1299553)
+    //
+    // For posterity, there are some undocumented event types
+    // (https://github.com/servo/cocoa-rs/issues/155)
+    // but that doesn't really matter here.
+    let event_type = unsafe { event.r#type() };
+    let modifier_flags = unsafe { event.modifierFlags() };
+    if event_type == NSEventType::KeyUp
+        && modifier_flags.contains(NSEventModifierFlags::NSEventModifierFlagCommand)
+    {
+        if let Some(key_window) = app.keyWindow() {
+            key_window.sendEvent(event);
         }
+        return;
     }
-);
+
+    // Events are generally scoped to the window level, so the best way
+    // to get device events is to listen for them on NSApplication.
+    let delegate = ApplicationDelegate::get(mtm);
+    maybe_dispatch_device_event(&delegate, event);
+
+    let _ = mtm;
+    let original = unsafe { ORIGINAL.get().expect("no existing sendEvent: handler set") };
+    original(app, sel, event)
+}
+
+/// Override the [`sendEvent:`][NSApplication::sendEvent] method on the given application class.
+///
+/// The previous implementation created a subclass of [`NSApplication`], however we would like to
+/// give the user full control over their `NSApplication`, so we override the method here using
+/// method swizzling instead.
+///
+/// This _should_ also allow two versions of Winit to exist in the same application.
+///
+/// See the following links for more info on method swizzling:
+/// - <https://nshipster.com/method-swizzling/>
+/// - <https://spin.atomicobject.com/method-swizzling-objective-c/>
+/// - <https://web.archive.org/web/20130308110627/http://cocoadev.com/wiki/MethodSwizzling>
+///
+/// NOTE: This function assumes that the passed in application object is the one returned from
+/// [`NSApplication::sharedApplication`], i.e. the one and only global shared application object.
+/// For testing though, we allow it to be a different object.
+pub(crate) fn override_send_event(global_app: &NSApplication) {
+    let mtm = MainThreadMarker::from(global_app);
+    let class = global_app.class();
+
+    let method =
+        class.instance_method(sel!(sendEvent:)).expect("NSApplication must have sendEvent: method");
+
+    // SAFETY: Converting our `sendEvent:` implementation to an IMP.
+    let overridden = unsafe { mem::transmute::<SendEvent, Imp>(send_event) };
+
+    // If we've already overridden the method, don't do anything.
+    // FIXME(madsmtm): Use `std::ptr::fn_addr_eq` (Rust 1.85) once available in MSRV.
+    #[allow(unknown_lints, unpredictable_function_pointer_comparisons)]
+    if overridden == method.implementation() {
+        return;
+    }
+
+    // SAFETY: Our implementation has:
+    // 1. The same signature as `sendEvent:`.
+    // 2. Does not impose extra safety requirements on callers.
+    let original = unsafe { method.set_implementation(overridden) };
+
+    // SAFETY: This is the actual signature of `sendEvent:`.
+    let original = unsafe { mem::transmute::<Imp, SendEvent>(original) };
+
+    // NOTE: If NSApplication was safe to use from multiple threads, then this would potentially be
+    // a (checked) race-condition, since one could call `sendEvent:` before the original had been
+    // stored here.
+    //
+    // It is only usable from the main thread, however, so we're good!
+    let _ = mtm;
+    unsafe { ORIGINAL.set(Some(original)) };
+}
 
 fn maybe_dispatch_device_event(delegate: &ApplicationDelegate, event: &NSEvent) {
     let event_type = unsafe { event.r#type() };
@@ -57,25 +112,27 @@ fn maybe_dispatch_device_event(delegate: &ApplicationDelegate, event: &NSEvent)
             let delta_y = unsafe { event.deltaY() } as f64;
 
             if delta_x != 0.0 {
-                delegate.queue_device_event(DeviceEvent::Motion { axis: 0, value: delta_x });
+                delegate.maybe_queue_device_event(DeviceEvent::Motion { axis: 0, value: delta_x });
             }
 
             if delta_y != 0.0 {
-                delegate.queue_device_event(DeviceEvent::Motion { axis: 1, value: delta_y })
+                delegate.maybe_queue_device_event(DeviceEvent::Motion { axis: 1, value: delta_y })
             }
 
             if delta_x != 0.0 || delta_y != 0.0 {
-                delegate.queue_device_event(DeviceEvent::MouseMotion { delta: (delta_x, delta_y) });
+                delegate.maybe_queue_device_event(DeviceEvent::MouseMotion {
+                    delta: (delta_x, delta_y),
+                });
             }
         },
         NSEventType::LeftMouseDown | NSEventType::RightMouseDown | NSEventType::OtherMouseDown => {
-            delegate.queue_device_event(DeviceEvent::Button {
+            delegate.maybe_queue_device_event(DeviceEvent::Button {
                 button: unsafe { event.buttonNumber() } as u32,
                 state: ElementState::Pressed,
             });
         },
         NSEventType::LeftMouseUp | NSEventType::RightMouseUp | NSEventType::OtherMouseUp => {
-            delegate.queue_device_event(DeviceEvent::Button {
+            delegate.maybe_queue_device_event(DeviceEvent::Button {
                 button: unsafe { event.buttonNumber() } as u32,
                 state: ElementState::Released,
             });
@@ -83,3 +140,56 @@ fn maybe_dispatch_device_event(delegate: &ApplicationDelegate, event: &NSEvent)
         _ => (),
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use objc2::rc::Retained;
+    use objc2::{declare_class, msg_send_id, mutability, ClassType, DeclaredClass};
+
+    use super::*;
+
+    #[test]
+    fn test_override() {
+        // FIXME(madsmtm): Ensure this always runs (maybe use cargo-nextest or `--test-threads=1`?)
+        let Some(mtm) = MainThreadMarker::new() else { return };
+
+        // Create a new application, without making it the shared application.
+        let app = unsafe { NSApplication::new(mtm) };
+        override_send_event(&app);
+        // Test calling twice works.
+        override_send_event(&app);
+
+        // FIXME(madsmtm): Can't test this yet, need some way to mock AppState.
+        // unsafe {
+        //     let event = super::super::event::dummy_event().unwrap();
+        //     app.sendEvent(&event)
+        // }
+    }
+
+    #[test]
+    fn test_custom_class() {
+        let Some(_mtm) = MainThreadMarker::new() else { return };
+
+        declare_class!(
+            struct TestApplication;
+
+            unsafe impl ClassType for TestApplication {
+                type Super = NSApplication;
+                type Mutability = mutability::MainThreadOnly;
+                const NAME: &'static str = "TestApplication";
+            }
+
+            impl DeclaredClass for TestApplication {}
+
+            unsafe impl TestApplication {
+                #[method(sendEvent:)]
+                fn send_event(&self, _event: &NSEvent) {
+                    todo!()
+                }
+            }
+        );
+
+        let app: Retained<TestApplication> = unsafe { msg_send_id![TestApplication::class(), new] };
+        override_send_event(&app);
+    }
+}

src/platform_impl/macos/app_state.rs

@@ -1,40 +1,29 @@
 use std::cell::{Cell, RefCell};
-use std::collections::VecDeque;
 use std::mem;
 use std::rc::Weak;
-use std::sync::{Arc, Mutex};
 use std::time::Instant;
 
 use objc2::rc::Retained;
-use objc2::runtime::AnyObject;
 use objc2::{declare_class, msg_send_id, mutability, ClassType, DeclaredClass};
-use objc2_app_kit::{NSApplication, NSApplicationActivationPolicy, NSApplicationDelegate};
-use objc2_foundation::{MainThreadMarker, NSObject, NSObjectProtocol, NSSize};
+use objc2_app_kit::{
+    NSApplication, NSApplicationActivationPolicy, NSApplicationDelegate, NSRunningApplication,
+};
+use objc2_foundation::{MainThreadMarker, NSNotification, NSObject, NSObjectProtocol};
 
 use super::event_handler::EventHandler;
-use super::event_loop::{stop_app_immediately, ActiveEventLoop, PanicInfo};
+use super::event_loop::{notify_windows_of_exit, stop_app_immediately, ActiveEventLoop, PanicInfo};
 use super::observer::{EventLoopWaker, RunLoop};
-use super::window::WinitWindow;
 use super::{menu, WindowId, DEVICE_ID};
-use crate::dpi::PhysicalSize;
-use crate::event::{DeviceEvent, Event, InnerSizeWriter, StartCause, WindowEvent};
+use crate::event::{DeviceEvent, Event, StartCause, WindowEvent};
 use crate::event_loop::{ActiveEventLoop as RootActiveEventLoop, ControlFlow};
 use crate::window::WindowId as RootWindowId;
 
 #[derive(Debug)]
-struct Policy(NSApplicationActivationPolicy);
-
-impl Default for Policy {
-    fn default() -> Self {
-        Self(NSApplicationActivationPolicy::Regular)
-    }
-}
-
-#[derive(Debug, Default)]
-pub(super) struct State {
-    activation_policy: Policy,
+pub(super) struct AppState {
+    activation_policy: Option<NSApplicationActivationPolicy>,
     default_menu: bool,
     activate_ignoring_other_apps: bool,
+    run_loop: RunLoop,
     event_handler: EventHandler,
     stop_on_launch: Cell<bool>,
     stop_before_wait: Cell<bool>,
@@ -50,7 +39,6 @@ pub(super) struct State {
     waker: RefCell<EventLoopWaker>,
     start_time: Cell<Option<Instant>>,
     wait_timeout: Cell<Option<Instant>>,
-    pending_events: RefCell<VecDeque<QueuedEvent>>,
     pending_redraw: RefCell<Vec<WindowId>>,
     // NOTE: This is strongly referenced by our `NSWindowDelegate` and our `NSView` subclass, and
     // as such should be careful to not add fields that, in turn, strongly reference those.
@@ -67,62 +55,20 @@ declare_class!(
     }
 
     impl DeclaredClass for ApplicationDelegate {
-        type Ivars = State;
+        type Ivars = AppState;
     }
 
     unsafe impl NSObjectProtocol for ApplicationDelegate {}
 
     unsafe impl NSApplicationDelegate for ApplicationDelegate {
-        // NOTE: This will, globally, only be run once, no matter how many
-        // `EventLoop`s the user creates.
         #[method(applicationDidFinishLaunching:)]
-        fn did_finish_launching(&self, _sender: Option<&AnyObject>) {
-            trace_scope!("applicationDidFinishLaunching:");
-            self.ivars().is_launched.set(true);
-
-            let mtm = MainThreadMarker::from(self);
-            let app = NSApplication::sharedApplication(mtm);
-            // We need to delay setting the activation policy and activating the app
-            // until `applicationDidFinishLaunching` has been called. Otherwise the
-            // menu bar is initially unresponsive on macOS 10.15.
-            app.setActivationPolicy(self.ivars().activation_policy.0);
-
-            window_activation_hack(&app);
-            #[allow(deprecated)]
-            app.activateIgnoringOtherApps(self.ivars().activate_ignoring_other_apps);
-
-            if self.ivars().default_menu {
-                // The menubar initialization should be before the `NewEvents` event, to allow
-                // overriding of the default menu even if it's created
-                menu::initialize(&app);
-            }
-
-            self.ivars().waker.borrow_mut().start();
-
-            self.set_is_running(true);
-            self.dispatch_init_events();
-
-            // If the application is being launched via `EventLoop::pump_app_events()` then we'll
-            // want to stop the app once it is launched (and return to the external loop)
-            //
-            // In this case we still want to consider Winit's `EventLoop` to be "running",
-            // so we call `start_running()` above.
-            if self.ivars().stop_on_launch.get() {
-                // NOTE: the original idea had been to only stop the underlying `RunLoop`
-                // for the app but that didn't work as expected (`-[NSApplication run]`
-                // effectively ignored the attempt to stop the RunLoop and re-started it).
-                //
-                // So we return from `pump_events` by stopping the application.
-                let app = NSApplication::sharedApplication(mtm);
-                stop_app_immediately(&app);
-            }
+        fn app_did_finish_launching(&self, notification: &NSNotification) {
+            self.did_finish_launching(notification)
         }
 
         #[method(applicationWillTerminate:)]
-        fn will_terminate(&self, _sender: Option<&AnyObject>) {
-            trace_scope!("applicationWillTerminate:");
-            // TODO: Notify every window that it will be destroyed, like done in iOS?
-            self.internal_exit();
+        fn app_will_terminate(&self, notification: &NSNotification) {
+            self.will_terminate(notification)
         }
     }
 );
@@ -130,19 +76,101 @@ declare_class!(
 impl ApplicationDelegate {
     pub(super) fn new(
         mtm: MainThreadMarker,
-        activation_policy: NSApplicationActivationPolicy,
+        activation_policy: Option<NSApplicationActivationPolicy>,
         default_menu: bool,
         activate_ignoring_other_apps: bool,
     ) -> Retained<Self> {
-        let this = mtm.alloc().set_ivars(State {
-            activation_policy: Policy(activation_policy),
+        let this = mtm.alloc().set_ivars(AppState {
+            activation_policy,
             default_menu,
             activate_ignoring_other_apps,
-            ..Default::default()
+            run_loop: RunLoop::main(mtm),
+            event_handler: EventHandler::new(),
+            stop_on_launch: Cell::new(false),
+            stop_before_wait: Cell::new(false),
+            stop_after_wait: Cell::new(false),
+            stop_on_redraw: Cell::new(false),
+            is_launched: Cell::new(false),
+            is_running: Cell::new(false),
+            exit: Cell::new(false),
+            control_flow: Cell::new(ControlFlow::default()),
+            waker: RefCell::new(EventLoopWaker::new()),
+            start_time: Cell::new(None),
+            wait_timeout: Cell::new(None),
+            pending_redraw: RefCell::new(vec![]),
         });
         unsafe { msg_send_id![super(this), init] }
     }
 
+    // NOTE: This will, globally, only be run once, no matter how many
+    // `EventLoop`s the user creates.
+    fn did_finish_launching(&self, _notification: &NSNotification) {
+        trace_scope!("applicationDidFinishLaunching:");
+        self.ivars().is_launched.set(true);
+
+        let mtm = MainThreadMarker::from(self);
+        let app = NSApplication::sharedApplication(mtm);
+        // We need to delay setting the activation policy and activating the app
+        // until `applicationDidFinishLaunching` has been called. Otherwise the
+        // menu bar is initially unresponsive on macOS 10.15.
+        // If no activation policy is explicitly provided, do not set it at all
+        // to allow the package manifest to define behavior via LSUIElement.
+        if let Some(activation_policy) = self.ivars().activation_policy {
+            app.setActivationPolicy(activation_policy);
+        } else {
+            // If no activation policy is explicitly provided, and the application
+            // is bundled, do not set the activation policy at all, to allow the
+            // package manifest to define the behavior via LSUIElement.
+            //
+            // See:
+            // - https://github.com/rust-windowing/winit/issues/261
+            // - https://github.com/rust-windowing/winit/issues/3958
+            let is_bundled =
+                unsafe { NSRunningApplication::currentApplication().bundleIdentifier().is_some() };
+            if !is_bundled {
+                app.setActivationPolicy(NSApplicationActivationPolicy::Regular);
+            }
+        }
+
+        window_activation_hack(&app);
+        #[allow(deprecated)]
+        app.activateIgnoringOtherApps(self.ivars().activate_ignoring_other_apps);
+
+        if self.ivars().default_menu {
+            // The menubar initialization should be before the `NewEvents` event, to allow
+            // overriding of the default menu even if it's created
+            menu::initialize(&app);
+        }
+
+        self.ivars().waker.borrow_mut().start();
+
+        self.set_is_running(true);
+        self.dispatch_init_events();
+
+        // If the application is being launched via `EventLoop::pump_app_events()` then we'll
+        // want to stop the app once it is launched (and return to the external loop)
+        //
+        // In this case we still want to consider Winit's `EventLoop` to be "running",
+        // so we call `start_running()` above.
+        if self.ivars().stop_on_launch.get() {
+            // NOTE: the original idea had been to only stop the underlying `RunLoop`
+            // for the app but that didn't work as expected (`-[NSApplication run]`
+            // effectively ignored the attempt to stop the RunLoop and re-started it).
+            //
+            // So we return from `pump_events` by stopping the application.
+            let app = NSApplication::sharedApplication(mtm);
+            stop_app_immediately(&app);
+        }
+    }
+
+    fn will_terminate(&self, _notification: &NSNotification) {
+        trace_scope!("applicationWillTerminate:");
+        let mtm = MainThreadMarker::from(self);
+        let app = NSApplication::sharedApplication(mtm);
+        notify_windows_of_exit(&app);
+        self.internal_exit();
+    }
+
     pub fn get(mtm: MainThreadMarker) -> Retained<Self> {
         let app = NSApplication::sharedApplication(mtm);
         let delegate =
@@ -193,7 +221,6 @@ impl ApplicationDelegate {
     /// NOTE: that if the `NSApplication` has been launched then that state is preserved,
     /// and we won't need to re-launch the app if subsequent EventLoops are run.
     pub fn internal_exit(&self) {
-        self.handle_event(Event::Suspended);
         self.handle_event(Event::LoopExiting);
 
         self.set_is_running(false);
@@ -235,28 +262,16 @@ impl ApplicationDelegate {
         self.ivars().control_flow.get()
     }
 
-    pub fn queue_window_event(&self, window_id: WindowId, event: WindowEvent) {
-        self.ivars()
-            .pending_events
-            .borrow_mut()
-            .push_back(QueuedEvent::WindowEvent(window_id, event));
+    pub fn maybe_queue_window_event(&self, window_id: WindowId, event: WindowEvent) {
+        self.maybe_queue_event(Event::WindowEvent { window_id: RootWindowId(window_id), event });
     }
 
-    pub fn queue_device_event(&self, event: DeviceEvent) {
-        self.ivars().pending_events.borrow_mut().push_back(QueuedEvent::DeviceEvent(event));
+    pub fn handle_window_event(&self, window_id: WindowId, event: WindowEvent) {
+        self.handle_event(Event::WindowEvent { window_id: RootWindowId(window_id), event });
     }
 
-    pub fn queue_static_scale_factor_changed_event(
-        &self,
-        window: Retained<WinitWindow>,
-        suggested_size: PhysicalSize<u32>,
-        scale_factor: f64,
-    ) {
-        self.ivars().pending_events.borrow_mut().push_back(QueuedEvent::ScaleFactorChanged {
-            window,
-            suggested_size,
-            scale_factor,
-        });
+    pub fn maybe_queue_device_event(&self, event: DeviceEvent) {
+        self.maybe_queue_event(Event::DeviceEvent { device_id: DEVICE_ID, event });
     }
 
     pub fn handle_redraw(&self, window_id: WindowId) {
@@ -284,9 +299,27 @@ impl ApplicationDelegate {
         if !pending_redraw.contains(&window_id) {
             pending_redraw.push(window_id);
         }
-        unsafe { RunLoop::get() }.wakeup();
+        self.ivars().run_loop.wakeup();
     }
 
+    #[track_caller]
+    fn maybe_queue_event(&self, event: Event<HandlePendingUserEvents>) {
+        // Most programmer actions in AppKit (e.g. change window fullscreen, set focused, etc.)
+        // result in an event being queued, and applied at a later point.
+        //
+        // However, it is not documented which actions do this, and which ones are done immediately,
+        // so to make sure that we don't encounter re-entrancy issues, we first check if we're
+        // currently handling another event, and if we are, we queue the event instead.
+        if !self.ivars().event_handler.in_use() {
+            self.handle_event(event);
+        } else {
+            tracing::debug!(?event, "had to queue event since another is currently being handled");
+            let this = self.retain();
+            self.ivars().run_loop.queue_closure(move || this.handle_event(event));
+        }
+    }
+
+    #[track_caller]
     fn handle_event(&self, event: Event<HandlePendingUserEvents>) {
         self.ivars().event_handler.handle_event(event, &ActiveEventLoop::new_root(self.retain()))
     }
@@ -348,49 +381,6 @@ impl ApplicationDelegate {
 
         self.handle_event(Event::UserEvent(HandlePendingUserEvents));
 
-        let events = mem::take(&mut *self.ivars().pending_events.borrow_mut());
-        for event in events {
-            match event {
-                QueuedEvent::WindowEvent(window_id, event) => {
-                    self.handle_event(Event::WindowEvent {
-                        window_id: RootWindowId(window_id),
-                        event,
-                    });
-                },
-                QueuedEvent::DeviceEvent(event) => {
-                    self.handle_event(Event::DeviceEvent { device_id: DEVICE_ID, event });
-                },
-                QueuedEvent::ScaleFactorChanged { window, suggested_size, scale_factor } => {
-                    let new_inner_size = Arc::new(Mutex::new(suggested_size));
-                    let scale_factor_changed_event = Event::WindowEvent {
-                        window_id: RootWindowId(window.id()),
-                        event: WindowEvent::ScaleFactorChanged {
-                            scale_factor,
-                            inner_size_writer: InnerSizeWriter::new(Arc::downgrade(
-                                &new_inner_size,
-                            )),
-                        },
-                    };
-
-                    self.handle_event(scale_factor_changed_event);
-
-                    let physical_size = *new_inner_size.lock().unwrap();
-                    drop(new_inner_size);
-                    if physical_size != suggested_size {
-                        let logical_size = physical_size.to_logical(scale_factor);
-                        let size = NSSize::new(logical_size.width, logical_size.height);
-                        window.setContentSize(size);
-                    }
-
-                    let resized_event = Event::WindowEvent {
-                        window_id: RootWindowId(window.id()),
-                        event: WindowEvent::Resized(physical_size),
-                    };
-                    self.handle_event(resized_event);
-                },
-            }
-        }
-
         let redraw = mem::take(&mut *self.ivars().pending_redraw.borrow_mut());
         for window_id in redraw {
             self.handle_event(Event::WindowEvent {
@@ -404,6 +394,7 @@ impl ApplicationDelegate {
         if self.exiting() {
             let app = NSApplication::sharedApplication(mtm);
             stop_app_immediately(&app);
+            notify_windows_of_exit(&app);
         }
 
         if self.ivars().stop_before_wait.get() {
@@ -421,17 +412,6 @@ impl ApplicationDelegate {
     }
 }
 
-#[derive(Debug)]
-pub(crate) enum QueuedEvent {
-    WindowEvent(WindowId, WindowEvent),
-    DeviceEvent(DeviceEvent),
-    ScaleFactorChanged {
-        window: Retained<WinitWindow>,
-        suggested_size: PhysicalSize<u32>,
-        scale_factor: f64,
-    },
-}
-
 #[derive(Debug)]
 pub(crate) struct HandlePendingUserEvents;
 

src/platform_impl/macos/cursor.rs

@@ -4,7 +4,7 @@ use std::sync::OnceLock;
 
 use objc2::rc::Retained;
 use objc2::runtime::Sel;
-use objc2::{msg_send_id, sel, ClassType};
+use objc2::{msg_send, msg_send_id, sel, ClassType};
 use objc2_app_kit::{NSBitmapImageRep, NSCursor, NSDeviceRGBColorSpace, NSImage};
 use objc2_foundation::{
     ns_string, NSData, NSDictionary, NSNumber, NSObject, NSObjectProtocol, NSPoint, NSSize,
@@ -66,7 +66,7 @@ pub(crate) fn default_cursor() -> Retained<NSCursor> {
 
 unsafe fn try_cursor_from_selector(sel: Sel) -> Option<Retained<NSCursor>> {
     let cls = NSCursor::class();
-    if cls.responds_to(sel) {
+    if msg_send![cls, respondsToSelector: sel] {
         let cursor: Retained<NSCursor> = unsafe { msg_send_id![cls, performSelector: sel] };
         Some(cursor)
     } else {

src/platform_impl/macos/event.rs

@@ -92,17 +92,12 @@ fn get_logical_key_char(ns_event: &NSEvent, modifierless_chars: &str) -> Key {
 /// Create `KeyEvent` for the given `NSEvent`.
 ///
 /// This function shouldn't be called when the IME input is in process.
-pub(crate) fn create_key_event(
-    ns_event: &NSEvent,
-    is_press: bool,
-    is_repeat: bool,
-    key_override: Option<PhysicalKey>,
-) -> KeyEvent {
+pub(crate) fn create_key_event(ns_event: &NSEvent, is_press: bool, is_repeat: bool) -> KeyEvent {
     use ElementState::{Pressed, Released};
     let state = if is_press { Pressed } else { Released };
 
     let scancode = unsafe { ns_event.keyCode() };
-    let mut physical_key = key_override.unwrap_or_else(|| scancode_to_physicalkey(scancode as u32));
+    let mut physical_key = scancode_to_physicalkey(scancode as u32);
 
     // NOTE: The logical key should heed both SHIFT and ALT if possible.
     // For instance:
@@ -111,20 +106,15 @@ pub(crate) fn create_key_event(
     // * Pressing CTRL SHIFT A: logical key should also be "A"
     // This is not easy to tease out of `NSEvent`, but we do our best.
 
-    let text_with_all_modifiers: Option<SmolStr> = if key_override.is_some() {
+    let characters = unsafe { ns_event.characters() }.map(|s| s.to_string()).unwrap_or_default();
+    let text_with_all_modifiers = if characters.is_empty() {
         None
     } else {
-        let characters =
-            unsafe { ns_event.characters() }.map(|s| s.to_string()).unwrap_or_default();
-        if characters.is_empty() {
-            None
-        } else {
-            if matches!(physical_key, PhysicalKey::Unidentified(_)) {
-                // The key may be one of the funky function keys
-                physical_key = extra_function_key_to_code(scancode, &characters);
-            }
-            Some(SmolStr::new(characters))
+        if matches!(physical_key, PhysicalKey::Unidentified(_)) {
+            // The key may be one of the funky function keys
+            physical_key = extra_function_key_to_code(scancode, &characters);
         }
+        Some(SmolStr::new(characters))
     };
 
     let key_from_code = code_to_key(physical_key, scancode);

src/platform_impl/macos/event_handler.rs

@@ -1,7 +1,7 @@
 use std::cell::RefCell;
 use std::{fmt, mem};
 
-use super::app_delegate::HandlePendingUserEvents;
+use super::app_state::HandlePendingUserEvents;
 use crate::event::Event;
 use crate::event_loop::ActiveEventLoop as RootActiveEventLoop;
 
@@ -16,7 +16,7 @@ impl fmt::Debug for EventHandlerData {
     }
 }
 
-#[derive(Debug, Default)]
+#[derive(Debug)]
 pub(crate) struct EventHandler {
     /// This can be in the following states:
     /// - Not registered by the event loop (None).
@@ -26,6 +26,10 @@ pub(crate) struct EventHandler {
 }
 
 impl EventHandler {
+    pub(crate) const fn new() -> Self {
+        Self { inner: RefCell::new(None) }
+    }
+
     /// Set the event loop handler for the duration of the given closure.
     ///
     /// This is similar to using the `scoped-tls` or `scoped-tls-hkt` crates

src/platform_impl/macos/event_loop.rs

@@ -16,16 +16,15 @@ use core_foundation::runloop::{
 };
 use objc2::rc::{autoreleasepool, Retained};
 use objc2::runtime::ProtocolObject;
-use objc2::{msg_send_id, ClassType};
+use objc2::sel;
 use objc2_app_kit::{NSApplication, NSApplicationActivationPolicy, NSWindow};
 use objc2_foundation::{MainThreadMarker, NSObjectProtocol};
 
-use super::app::WinitApplication;
-use super::app_delegate::{ApplicationDelegate, HandlePendingUserEvents};
+use super::app::override_send_event;
+use super::app_state::{ApplicationDelegate, HandlePendingUserEvents};
 use super::event::dummy_event;
 use super::monitor::{self, MonitorHandle};
 use super::observer::setup_control_flow_observers;
-use crate::application::ApplicationHandler;
 use crate::error::EventLoopError;
 use crate::event::Event;
 use crate::event_loop::{
@@ -34,7 +33,7 @@ use crate::event_loop::{
 use crate::platform::macos::ActivationPolicy;
 use crate::platform::pump_events::PumpStatus;
 use crate::platform_impl::platform::cursor::CustomCursor;
-use crate::window::{CustomCursor as RootCustomCursor, CustomCursorSource};
+use crate::window::{CustomCursor as RootCustomCursor, CustomCursorSource, Theme};
 
 #[derive(Default)]
 pub struct PanicInfo {
@@ -107,6 +106,17 @@ impl ActiveEventLoop {
         rwh_05::RawDisplayHandle::AppKit(rwh_05::AppKitDisplayHandle::empty())
     }
 
+    #[inline]
+    pub fn system_theme(&self) -> Option<Theme> {
+        let app = NSApplication::sharedApplication(self.mtm);
+
+        if app.respondsToSelector(sel!(effectiveAppearance)) {
+            Some(super::window_delegate::appearance_to_theme(&app.effectiveAppearance()))
+        } else {
+            Some(Theme::Light)
+        }
+    }
+
     #[cfg(feature = "rwh_06")]
     #[inline]
     pub fn raw_display_handle_rwh_06(
@@ -156,28 +166,17 @@ impl ActiveEventLoop {
     }
 }
 
-fn map_user_event<T: 'static, A: ApplicationHandler<T>>(
-    app: &mut A,
+fn map_user_event<T: 'static>(
+    mut handler: impl FnMut(Event<T>, &RootWindowTarget),
     receiver: Rc<mpsc::Receiver<T>>,
-) -> impl FnMut(Event<HandlePendingUserEvents>, &RootWindowTarget) + '_ {
-    move |event, window_target| match event {
-        Event::NewEvents(cause) => app.new_events(window_target, cause),
-        Event::WindowEvent { window_id, event } => {
-            app.window_event(window_target, window_id, event)
-        },
-        Event::DeviceEvent { device_id, event } => {
-            app.device_event(window_target, device_id, event)
-        },
-        Event::UserEvent(_) => {
+) -> impl FnMut(Event<HandlePendingUserEvents>, &RootWindowTarget) {
+    move |event, window_target| match event.map_nonuser_event() {
+        Ok(event) => (handler)(event, window_target),
+        Err(_) => {
             for event in receiver.try_iter() {
-                app.user_event(window_target, event);
+                (handler)(Event::UserEvent(event), window_target);
             }
         },
-        Event::Suspended => app.suspended(window_target),
-        Event::Resumed => app.resumed(window_target),
-        Event::AboutToWait => app.about_to_wait(window_target),
-        Event::LoopExiting => app.exiting(window_target),
-        Event::MemoryWarning => app.memory_warning(window_target),
     }
 }
 
@@ -203,18 +202,14 @@ pub struct EventLoop<T: 'static> {
 
 #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
 pub(crate) struct PlatformSpecificEventLoopAttributes {
-    pub(crate) activation_policy: ActivationPolicy,
+    pub(crate) activation_policy: Option<ActivationPolicy>,
     pub(crate) default_menu: bool,
     pub(crate) activate_ignoring_other_apps: bool,
 }
 
 impl Default for PlatformSpecificEventLoopAttributes {
     fn default() -> Self {
-        Self {
-            activation_policy: Default::default(), // Regular
-            default_menu: true,
-            activate_ignoring_other_apps: true,
-        }
+        Self { activation_policy: None, default_menu: true, activate_ignoring_other_apps: true }
     }
 }
 
@@ -225,20 +220,14 @@ impl<T> EventLoop<T> {
         let mtm = MainThreadMarker::new()
             .expect("on macOS, `EventLoop` must be created on the main thread!");
 
-        let app: Retained<NSApplication> =
-            unsafe { msg_send_id![WinitApplication::class(), sharedApplication] };
-
-        if !app.is_kind_of::<WinitApplication>() {
-            panic!(
-                "`winit` requires control over the principal class. You must create the event \
-                 loop before other parts of your application initialize NSApplication"
-            );
-        }
+        // Initialize the application (if it has not already been).
+        let app = NSApplication::sharedApplication(mtm);
 
         let activation_policy = match attributes.activation_policy {
-            ActivationPolicy::Regular => NSApplicationActivationPolicy::Regular,
-            ActivationPolicy::Accessory => NSApplicationActivationPolicy::Accessory,
-            ActivationPolicy::Prohibited => NSApplicationActivationPolicy::Prohibited,
+            None => None,
+            Some(ActivationPolicy::Regular) => Some(NSApplicationActivationPolicy::Regular),
+            Some(ActivationPolicy::Accessory) => Some(NSApplicationActivationPolicy::Accessory),
+            Some(ActivationPolicy::Prohibited) => Some(NSApplicationActivationPolicy::Prohibited),
         };
         let delegate = ApplicationDelegate::new(
             mtm,
@@ -251,8 +240,11 @@ impl<T> EventLoop<T> {
             app.setDelegate(Some(ProtocolObject::from_ref(&*delegate)));
         });
 
+        // Override `sendEvent:` on the application to forward to our application state.
+        override_send_event(&app);
+
         let panic_info: Rc<PanicInfo> = Default::default();
-        setup_control_flow_observers(Rc::downgrade(&panic_info));
+        setup_control_flow_observers(mtm, Rc::downgrade(&panic_info));
 
         let (sender, receiver) = mpsc::channel();
         Ok(EventLoop {
@@ -272,19 +264,22 @@ impl<T> EventLoop<T> {
         &self.window_target
     }
 
-    pub fn run_app<A: ApplicationHandler<T>>(mut self, app: &mut A) -> Result<(), EventLoopError> {
-        self.run_app_on_demand(app)
+    pub fn run<F>(mut self, handler: F) -> Result<(), EventLoopError>
+    where
+        F: FnMut(Event<T>, &RootWindowTarget),
+    {
+        self.run_on_demand(handler)
     }
 
     // NB: we don't base this on `pump_events` because for `MacOs` we can't support
     // `pump_events` elegantly (we just ask to run the loop for a "short" amount of
     // time and so a layered implementation would end up using a lot of CPU due to
     // redundant wake ups.
-    pub fn run_app_on_demand<A: ApplicationHandler<T>>(
-        &mut self,
-        app: &mut A,
-    ) -> Result<(), EventLoopError> {
-        let handler = map_user_event(app, self.receiver.clone());
+    pub fn run_on_demand<F>(&mut self, handler: F) -> Result<(), EventLoopError>
+    where
+        F: FnMut(Event<T>, &RootWindowTarget),
+    {
+        let handler = map_user_event(handler, self.receiver.clone());
 
         self.delegate.set_event_handler(handler, || {
             autoreleasepool(|_| {
@@ -319,12 +314,11 @@ impl<T> EventLoop<T> {
         Ok(())
     }
 
-    pub fn pump_app_events<A: ApplicationHandler<T>>(
-        &mut self,
-        timeout: Option<Duration>,
-        app: &mut A,
-    ) -> PumpStatus {
-        let handler = map_user_event(app, self.receiver.clone());
+    pub fn pump_events<F>(&mut self, timeout: Option<Duration>, handler: F) -> PumpStatus
+    where
+        F: FnMut(Event<T>, &RootWindowTarget),
+    {
+        let handler = map_user_event(handler, self.receiver.clone());
 
         self.delegate.set_event_handler(handler, || {
             autoreleasepool(|_| {
@@ -423,6 +417,22 @@ pub(super) fn stop_app_immediately(app: &NSApplication) {
     });
 }
 
+/// Tell all windows to close.
+///
+/// This will synchronously trigger `WindowEvent::Destroyed` within
+/// `windowWillClose:`, giving the application one last chance to handle
+/// those events. It doesn't matter if the user also ends up closing the
+/// windows in `Window`'s `Drop` impl, once a window has been closed once, it
+/// stays closed.
+///
+/// This ensures that no windows linger on after the event loop has exited,
+/// see <https://github.com/rust-windowing/winit/issues/4135>.
+pub(super) fn notify_windows_of_exit(app: &NSApplication) {
+    for window in app.windows() {
+        window.close();
+    }
+}
+
 /// Catches panics that happen inside `f` and when a panic
 /// happens, stops the `sharedApplication`
 #[inline]
@@ -492,8 +502,7 @@ impl<T> EventLoopProxy<T> {
                 cancel: None,
                 perform: event_loop_proxy_handler,
             };
-            let source =
-                CFRunLoopSourceCreate(ptr::null_mut(), CFIndex::max_value() - 1, &mut context);
+            let source = CFRunLoopSourceCreate(ptr::null_mut(), CFIndex::MAX - 1, &mut context);
             CFRunLoopAddSource(rl, source, kCFRunLoopCommonModes);
             CFRunLoopWakeUp(rl);
 

src/platform_impl/macos/ffi.rs

@@ -68,6 +68,8 @@ pub type CGDisplayModeRef = *mut c_void;
 #[link(name = "ApplicationServices", kind = "framework")]
 extern "C" {
     pub fn CGDisplayCreateUUIDFromDisplayID(display: CGDirectDisplayID) -> CFUUIDRef;
+
+    pub fn CGDisplayGetDisplayIDFromUUID(uuid: CFUUIDRef) -> CGDirectDisplayID;
 }
 
 #[link(name = "CoreGraphics", kind = "framework")]

src/platform_impl/macos/mod.rs

@@ -2,7 +2,7 @@
 mod util;
 
 mod app;
-mod app_delegate;
+mod app_state;
 mod cursor;
 mod event;
 mod event_handler;
@@ -37,7 +37,7 @@ pub(crate) use crate::platform_impl::Fullscreen;
 pub struct DeviceId;
 
 impl DeviceId {
-    pub const unsafe fn dummy() -> Self {
+    pub const fn dummy() -> Self {
         DeviceId
     }
 }

src/platform_impl/macos/monitor.rs

@@ -6,6 +6,7 @@ use std::fmt;
 use core_foundation::array::{CFArrayGetCount, CFArrayGetValueAtIndex};
 use core_foundation::base::{CFRelease, TCFType};
 use core_foundation::string::CFString;
+use core_foundation::uuid::{CFUUIDGetUUIDBytes, CFUUID};
 use core_graphics::display::{
     CGDirectDisplayID, CGDisplay, CGDisplayBounds, CGDisplayCopyDisplayMode,
 };
@@ -13,6 +14,7 @@ use objc2::rc::Retained;
 use objc2::runtime::AnyObject;
 use objc2_app_kit::NSScreen;
 use objc2_foundation::{ns_string, run_on_main, MainThreadMarker, NSNumber, NSPoint, NSRect};
+use tracing::warn;
 
 use super::ffi;
 use crate::dpi::{LogicalPosition, PhysicalPosition, PhysicalSize};
@@ -97,18 +99,71 @@ impl VideoModeHandle {
     }
 }
 
+/// `CGDirectDisplayID` is documented as:
+/// > a framebuffer, a color correction (gamma) table, and possibly an attached monitor.
+///
+/// That is, it doesn't actually represent the monitor itself. Instead, we use the UUID of the
+/// monitor, as retrieved from `CGDisplayCreateUUIDFromDisplayID` (this makes the monitor ID stable,
+/// even across reboots and video mode changes).
+///
+/// NOTE: I'd be perfectly valid to store `[u8; 16]` in here instead, we only store `CFUUID` to
+/// avoid having to re-create it when we want to fetch the display ID.
 #[derive(Clone)]
-pub struct MonitorHandle(CGDirectDisplayID);
+pub struct MonitorHandle(CFUUID);
+
+// SAFETY: CFUUID is immutable.
+// FIXME(madsmtm): Upstream this into `objc2-core-foundation`.
+unsafe impl Send for MonitorHandle {}
+unsafe impl Sync for MonitorHandle {}
+
+type MonitorUuid = [u8; 16];
+
+impl MonitorHandle {
+    /// Internal comparisons of [`MonitorHandle`]s are done first requesting a UUID for the handle.
+    fn uuid(&self) -> MonitorUuid {
+        let uuid = unsafe { CFUUIDGetUUIDBytes(self.0.as_concrete_TypeRef()) };
+        MonitorUuid::from([
+            uuid.byte0,
+            uuid.byte1,
+            uuid.byte2,
+            uuid.byte3,
+            uuid.byte4,
+            uuid.byte5,
+            uuid.byte6,
+            uuid.byte7,
+            uuid.byte8,
+            uuid.byte9,
+            uuid.byte10,
+            uuid.byte11,
+            uuid.byte12,
+            uuid.byte13,
+            uuid.byte14,
+            uuid.byte15,
+        ])
+    }
+
+    fn display_id(&self) -> CGDirectDisplayID {
+        unsafe { ffi::CGDisplayGetDisplayIDFromUUID(self.0.as_concrete_TypeRef()) }
+    }
+
+    #[track_caller]
+    pub(crate) fn new(display_id: CGDirectDisplayID) -> Option<Self> {
+        // kCGNullDirectDisplay
+        if display_id == 0 {
+            // `CGDisplayCreateUUIDFromDisplayID` checks kCGNullDirectDisplay internally.
+            warn!("constructing monitor from invalid display ID 0; falling back to main monitor");
+        }
+        let ptr = unsafe { ffi::CGDisplayCreateUUIDFromDisplayID(display_id) };
+        if ptr.is_null() {
+            return None;
+        }
+        Some(Self(unsafe { CFUUID::wrap_under_create_rule(ptr) }))
+    }
+}
 
-// `CGDirectDisplayID` changes on video mode change, so we cannot rely on that
-// for comparisons, but we can use `CGDisplayCreateUUIDFromDisplayID` to get an
-// unique identifier that persists even across system reboots
 impl PartialEq for MonitorHandle {
     fn eq(&self, other: &Self) -> bool {
-        unsafe {
-            ffi::CGDisplayCreateUUIDFromDisplayID(self.0)
-                == ffi::CGDisplayCreateUUIDFromDisplayID(other.0)
-        }
+        self.uuid() == other.uuid()
     }
 }
 
@@ -122,18 +177,13 @@ impl PartialOrd for MonitorHandle {
 
 impl Ord for MonitorHandle {
     fn cmp(&self, other: &Self) -> std::cmp::Ordering {
-        unsafe {
-            ffi::CGDisplayCreateUUIDFromDisplayID(self.0)
-                .cmp(&ffi::CGDisplayCreateUUIDFromDisplayID(other.0))
-        }
+        self.uuid().cmp(&other.uuid())
     }
 }
 
 impl std::hash::Hash for MonitorHandle {
     fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
-        unsafe {
-            ffi::CGDisplayCreateUUIDFromDisplayID(self.0).hash(state);
-        }
+        self.uuid().hash(state);
     }
 }
 
@@ -141,7 +191,8 @@ pub fn available_monitors() -> VecDeque<MonitorHandle> {
     if let Ok(displays) = CGDisplay::active_displays() {
         let mut monitors = VecDeque::with_capacity(displays.len());
         for display in displays {
-            monitors.push_back(MonitorHandle(display));
+            // Display ID just fetched from `CGGetActiveDisplayList`, should be fine to unwrap.
+            monitors.push_back(MonitorHandle::new(display).expect("invalid display ID"));
         }
         monitors
     } else {
@@ -150,7 +201,8 @@ pub fn available_monitors() -> VecDeque<MonitorHandle> {
 }
 
 pub fn primary_monitor() -> MonitorHandle {
-    MonitorHandle(CGDisplay::main().id)
+    // Display ID just fetched from `CGMainDisplayID`, should be fine to unwrap.
+    MonitorHandle::new(CGDisplay::main().id).expect("invalid display ID")
 }
 
 impl fmt::Debug for MonitorHandle {
@@ -167,26 +219,20 @@ impl fmt::Debug for MonitorHandle {
 }
 
 impl MonitorHandle {
-    pub fn new(id: CGDirectDisplayID) -> Self {
-        MonitorHandle(id)
-    }
-
     // TODO: Be smarter about this:
     // <https://github.com/glfw/glfw/blob/57cbded0760a50b9039ee0cb3f3c14f60145567c/src/cocoa_monitor.m#L44-L126>
     pub fn name(&self) -> Option<String> {
-        let MonitorHandle(display_id) = *self;
-        let screen_num = CGDisplay::new(display_id).model_number();
+        let screen_num = CGDisplay::new(self.display_id()).model_number();
         Some(format!("Monitor #{screen_num}"))
     }
 
     #[inline]
     pub fn native_identifier(&self) -> u32 {
-        self.0
+        self.display_id()
     }
 
     pub fn size(&self) -> PhysicalSize<u32> {
-        let MonitorHandle(display_id) = *self;
-        let display = CGDisplay::new(display_id);
+        let display = CGDisplay::new(self.display_id());
         let height = display.pixels_high();
         let width = display.pixels_wide();
         PhysicalSize::from_logical::<_, f64>((width as f64, height as f64), self.scale_factor())
@@ -213,14 +259,15 @@ impl MonitorHandle {
 
     pub fn refresh_rate_millihertz(&self) -> Option<u32> {
         unsafe {
-            let current_display_mode = NativeDisplayMode(CGDisplayCopyDisplayMode(self.0) as _);
+            let current_display_mode =
+                NativeDisplayMode(CGDisplayCopyDisplayMode(self.display_id()) as _);
             let refresh_rate = ffi::CGDisplayModeGetRefreshRate(current_display_mode.0);
             if refresh_rate > 0.0 {
                 return Some((refresh_rate * 1000.0).round() as u32);
             }
 
             let mut display_link = std::ptr::null_mut();
-            if ffi::CVDisplayLinkCreateWithCGDisplay(self.0, &mut display_link)
+            if ffi::CVDisplayLinkCreateWithCGDisplay(self.display_id(), &mut display_link)
                 != ffi::kCVReturnSuccess
             {
                 return None;
@@ -243,27 +290,34 @@ impl MonitorHandle {
 
         unsafe {
             let modes = {
-                let array = ffi::CGDisplayCopyAllDisplayModes(self.0, std::ptr::null());
-                assert!(!array.is_null(), "failed to get list of display modes");
-                let array_count = CFArrayGetCount(array);
-                let modes: Vec<_> = (0..array_count)
-                    .map(move |i| {
-                        let mode = CFArrayGetValueAtIndex(array, i) as *mut _;
-                        ffi::CGDisplayModeRetain(mode);
-                        mode
-                    })
-                    .collect();
-                CFRelease(array as *const _);
-                modes
+                let array = ffi::CGDisplayCopyAllDisplayModes(self.display_id(), std::ptr::null());
+                if array.is_null() {
+                    // Occasionally, certain CalDigit Thunderbolt Hubs report a spurious monitor
+                    // during sleep/wake/cycling monitors. It tends to have null
+                    // or 1 video mode only. See <https://github.com/bevyengine/bevy/issues/17827>.
+                    warn!(monitor = ?self, "failed to get a list of display modes");
+                    Vec::new()
+                } else {
+                    let array_count = CFArrayGetCount(array);
+                    let modes: Vec<_> = (0..array_count)
+                        .map(move |i| {
+                            let mode = CFArrayGetValueAtIndex(array, i) as *mut _;
+                            ffi::CGDisplayModeRetain(mode);
+                            mode
+                        })
+                        .collect();
+                    CFRelease(array as *const _);
+                    modes
+                }
             };
 
             modes.into_iter().map(move |mode| {
-                let cg_refresh_rate_hertz = ffi::CGDisplayModeGetRefreshRate(mode).round() as i64;
+                let cg_refresh_rate_hertz = ffi::CGDisplayModeGetRefreshRate(mode);
 
                 // CGDisplayModeGetRefreshRate returns 0.0 for any display that
                 // isn't a CRT
-                let refresh_rate_millihertz = if cg_refresh_rate_hertz > 0 {
-                    (cg_refresh_rate_hertz * 1000) as u32
+                let refresh_rate_millihertz = if cg_refresh_rate_hertz > 0.0 {
+                    (cg_refresh_rate_hertz * 1000.0).round() as u32
                 } else {
                     refresh_rate_millihertz
                 };
@@ -296,13 +350,17 @@ impl MonitorHandle {
     }
 
     pub(crate) fn ns_screen(&self, mtm: MainThreadMarker) -> Option<Retained<NSScreen>> {
-        let uuid = unsafe { ffi::CGDisplayCreateUUIDFromDisplayID(self.0) };
+        let uuid = self.uuid();
         NSScreen::screens(mtm).into_iter().find(|screen| {
             let other_native_id = get_display_id(screen);
-            let other_uuid = unsafe {
-                ffi::CGDisplayCreateUUIDFromDisplayID(other_native_id as CGDirectDisplayID)
-            };
-            uuid == other_uuid
+            if let Some(other) = MonitorHandle::new(other_native_id) {
+                uuid == other.uuid()
+            } else {
+                // Display ID was just fetched from live NSScreen, but can still result in `None`
+                // with certain Thunderbolt docked monitors.
+                warn!(other_native_id, "comparing against screen with invalid display ID");
+                false
+            }
         })
     }
 }

src/platform_impl/macos/observer.rs

@@ -1,21 +1,28 @@
+//! Utilities for working with `CFRunLoop`.
+//!
+//! See Apple's documentation on Run Loops for details:
+//! <https://developer.apple.com/library/archive/documentation/Cocoa/Conceptual/Multithreading/RunLoopManagement/RunLoopManagement.html>
+use std::cell::Cell;
 use std::ffi::c_void;
 use std::panic::{AssertUnwindSafe, UnwindSafe};
 use std::ptr;
 use std::rc::Weak;
 use std::time::Instant;
 
-use core_foundation::base::{CFIndex, CFOptionFlags, CFRelease};
+use block2::Block;
+use core_foundation::base::{CFIndex, CFOptionFlags, CFRelease, CFTypeRef};
 use core_foundation::date::CFAbsoluteTimeGetCurrent;
 use core_foundation::runloop::{
-    kCFRunLoopAfterWaiting, kCFRunLoopBeforeWaiting, kCFRunLoopCommonModes, kCFRunLoopExit,
-    CFRunLoopActivity, CFRunLoopAddObserver, CFRunLoopAddTimer, CFRunLoopGetMain,
+    kCFRunLoopAfterWaiting, kCFRunLoopBeforeWaiting, kCFRunLoopCommonModes, kCFRunLoopDefaultMode,
+    kCFRunLoopExit, CFRunLoopActivity, CFRunLoopAddObserver, CFRunLoopAddTimer, CFRunLoopGetMain,
     CFRunLoopObserverCallBack, CFRunLoopObserverContext, CFRunLoopObserverCreate,
     CFRunLoopObserverRef, CFRunLoopRef, CFRunLoopTimerCreate, CFRunLoopTimerInvalidate,
     CFRunLoopTimerRef, CFRunLoopTimerSetNextFireDate, CFRunLoopWakeUp,
 };
 use objc2_foundation::MainThreadMarker;
+use tracing::error;
 
-use super::app_delegate::ApplicationDelegate;
+use super::app_state::ApplicationDelegate;
 use super::event_loop::{stop_app_on_panic, PanicInfo};
 use super::ffi;
 
@@ -84,10 +91,20 @@ extern "C" fn control_flow_end_handler(
     }
 }
 
+#[derive(Debug)]
 pub struct RunLoop(CFRunLoopRef);
 
+impl Default for RunLoop {
+    fn default() -> Self {
+        Self(ptr::null_mut())
+    }
+}
+
 impl RunLoop {
-    pub unsafe fn get() -> Self {
+    pub fn main(mtm: MainThreadMarker) -> Self {
+        // SAFETY: We have a MainThreadMarker here, which means we know we're on the main thread, so
+        // scheduling (and scheduling a non-`Send` block) to that thread is allowed.
+        let _ = mtm;
         RunLoop(unsafe { CFRunLoopGetMain() })
     }
 
@@ -114,9 +131,79 @@ impl RunLoop {
         };
         unsafe { CFRunLoopAddObserver(self.0, observer, kCFRunLoopCommonModes) };
     }
+
+    /// Submit a closure to run on the main thread as the next step in the run loop, before other
+    /// event sources are processed.
+    ///
+    /// This is used for running event handlers, as those are not allowed to run re-entrantly.
+    ///
+    /// # Implementation
+    ///
+    /// This queuing could be implemented in the following several ways with subtle differences in
+    /// timing. This list is sorted in rough order in which they are run:
+    ///
+    /// 1. Using `CFRunLoopPerformBlock` or `-[NSRunLoop performBlock:]`.
+    ///
+    /// 2. Using `-[NSObject performSelectorOnMainThread:withObject:waitUntilDone:]` or wrapping the
+    ///    event in `NSEvent` and posting that to `-[NSApplication postEvent:atStart:]` (both
+    ///    creates a custom `CFRunLoopSource`, and signals that to wake up the main event loop).
+    ///
+    ///    a. `atStart = true`.
+    ///
+    ///    b. `atStart = false`.
+    ///
+    /// 3. `dispatch_async` or `dispatch_async_f`. Note that this may appear before 2b, it does not
+    ///    respect the ordering that runloop events have.
+    ///
+    /// We choose the first one, both for ease-of-implementation, but mostly for consistency, as we
+    /// want the event to be queued in a way that preserves the order the events originally arrived
+    /// in.
+    ///
+    /// As an example, let's assume that we receive two events from the user, a mouse click which we
+    /// handled by queuing it, and a window resize which we handled immediately. If we allowed
+    /// AppKit to choose the ordering when queuing the mouse event, it might get put in the back of
+    /// the queue, and the events would appear out of order to the user of Winit. So we must instead
+    /// put the event at the very front of the queue, to be handled as soon as possible after
+    /// handling whatever event it's currently handling.
+    pub fn queue_closure(&self, closure: impl FnOnce() + 'static) {
+        extern "C" {
+            fn CFRunLoopPerformBlock(rl: CFRunLoopRef, mode: CFTypeRef, block: &Block<dyn Fn()>);
+        }
+
+        // Convert `FnOnce()` to `Block<dyn Fn()>`.
+        let closure = Cell::new(Some(closure));
+        let block = block2::RcBlock::new(move || {
+            if let Some(closure) = closure.take() {
+                closure()
+            } else {
+                error!("tried to execute queued closure on main thread twice");
+            }
+        });
+
+        // There are a few common modes (`kCFRunLoopCommonModes`) defined by Cocoa:
+        // - `NSDefaultRunLoopMode`, alias of `kCFRunLoopDefaultMode`.
+        // - `NSEventTrackingRunLoopMode`, used when mouse-dragging and live-resizing a window.
+        // - `NSModalPanelRunLoopMode`, used when running a modal inside the Winit event loop.
+        // - `NSConnectionReplyMode`: TODO.
+        //
+        // We only want to run event handlers in the default mode, as we support running a blocking
+        // modal inside a Winit event handler (see [#1779]) which outrules the modal panel mode, and
+        // resizing such panel window enters the event tracking run loop mode, so we can't directly
+        // trigger events inside that mode either.
+        //
+        // Any events that are queued while running a modal or when live-resizing will instead wait,
+        // and be delivered to the application afterwards.
+        //
+        // [#1779]: https://github.com/rust-windowing/winit/issues/1779
+        let mode = unsafe { kCFRunLoopDefaultMode as CFTypeRef };
+
+        // SAFETY: The runloop is valid, the mode is a `CFStringRef`, and the block is `'static`.
+        unsafe { CFRunLoopPerformBlock(self.0, mode, &block) }
+    }
 }
 
-pub fn setup_control_flow_observers(panic_info: Weak<PanicInfo>) {
+pub fn setup_control_flow_observers(mtm: MainThreadMarker, panic_info: Weak<PanicInfo>) {
+    let run_loop = RunLoop::main(mtm);
     unsafe {
         let mut context = CFRunLoopObserverContext {
             info: Weak::into_raw(panic_info) as *mut _,
@@ -125,16 +212,15 @@ pub fn setup_control_flow_observers(panic_info: Weak<PanicInfo>) {
             release: None,
             copyDescription: None,
         };
-        let run_loop = RunLoop::get();
         run_loop.add_observer(
             kCFRunLoopAfterWaiting,
-            CFIndex::min_value(),
+            CFIndex::MIN,
             control_flow_begin_handler,
             &mut context as *mut _,
         );
         run_loop.add_observer(
             kCFRunLoopExit | kCFRunLoopBeforeWaiting,
-            CFIndex::max_value(),
+            CFIndex::MAX,
             control_flow_end_handler,
             &mut context as *mut _,
         );
@@ -165,8 +251,8 @@ impl Drop for EventLoopWaker {
     }
 }
 
-impl Default for EventLoopWaker {
-    fn default() -> EventLoopWaker {
+impl EventLoopWaker {
+    pub(crate) fn new() -> Self {
         extern "C" fn wakeup_main_loop(_timer: CFRunLoopTimerRef, _info: *mut c_void) {}
         unsafe {
             // Create a timer with a 0.1µs interval (1ns does not work) to mimic polling.
@@ -174,7 +260,7 @@ impl Default for EventLoopWaker {
             // future, but that gets changed to fire immediately in did_finish_launching
             let timer = CFRunLoopTimerCreate(
                 ptr::null_mut(),
-                std::f64::MAX,
+                f64::MAX,
                 0.000_000_1,
                 0,
                 0,
@@ -182,23 +268,21 @@ impl Default for EventLoopWaker {
                 ptr::null_mut(),
             );
             CFRunLoopAddTimer(CFRunLoopGetMain(), timer, kCFRunLoopCommonModes);
-            EventLoopWaker { timer, start_instant: Instant::now(), next_fire_date: None }
+            Self { timer, start_instant: Instant::now(), next_fire_date: None }
         }
     }
-}
 
-impl EventLoopWaker {
     pub fn stop(&mut self) {
         if self.next_fire_date.is_some() {
             self.next_fire_date = None;
-            unsafe { CFRunLoopTimerSetNextFireDate(self.timer, std::f64::MAX) }
+            unsafe { CFRunLoopTimerSetNextFireDate(self.timer, f64::MAX) }
         }
     }
 
     pub fn start(&mut self) {
         if self.next_fire_date != Some(self.start_instant) {
             self.next_fire_date = Some(self.start_instant);
-            unsafe { CFRunLoopTimerSetNextFireDate(self.timer, std::f64::MIN) }
+            unsafe { CFRunLoopTimerSetNextFireDate(self.timer, f64::MIN) }
         }
     }
 

src/platform_impl/macos/view.rs

@@ -16,17 +16,17 @@ use objc2_foundation::{
     NSPoint, NSRange, NSRect, NSSize, NSString, NSUInteger,
 };
 
-use super::app_delegate::ApplicationDelegate;
+use super::app_state::ApplicationDelegate;
 use super::cursor::{default_cursor, invisible_cursor};
 use super::event::{
     code_to_key, code_to_location, create_key_event, event_mods, lalt_pressed, ralt_pressed,
-    scancode_to_physicalkey,
+    scancode_to_physicalkey, KeyEventExtra,
 };
 use super::window::WinitWindow;
 use super::DEVICE_ID;
 use crate::dpi::{LogicalPosition, LogicalSize};
 use crate::event::{
-    DeviceEvent, ElementState, Ime, Modifiers, MouseButton, MouseScrollDelta, TouchPhase,
+    DeviceEvent, ElementState, Ime, KeyEvent, Modifiers, MouseButton, MouseScrollDelta, TouchPhase,
     WindowEvent,
 };
 use crate::keyboard::{Key, KeyCode, KeyLocation, ModifiersState, NamedKey};
@@ -270,19 +270,20 @@ declare_class!(
         fn set_marked_text(
             &self,
             string: &NSObject,
-            _selected_range: NSRange,
+            selected_range: NSRange,
             _replacement_range: NSRange,
         ) {
+            // TODO: Use _replacement_range, requires changing the event to report surrounding text.
             trace_scope!("setMarkedText:selectedRange:replacementRange:");
 
             // SAFETY: This method is guaranteed to get either a `NSString` or a `NSAttributedString`.
-            let (marked_text, preedit_string) = if string.is_kind_of::<NSAttributedString>() {
+            let (marked_text, string) = if string.is_kind_of::<NSAttributedString>() {
                 let string: *const NSObject = string;
                 let string: *const NSAttributedString = string.cast();
                 let string = unsafe { &*string };
                 (
                     NSMutableAttributedString::from_attributed_nsstring(string),
-                    string.string().to_string(),
+                    string.string(),
                 )
             } else {
                 let string: *const NSObject = string;
@@ -290,7 +291,7 @@ declare_class!(
                 let string = unsafe { &*string };
                 (
                     NSMutableAttributedString::from_nsstring(string),
-                    string.to_string(),
+                    string.copy(),
                 )
             };
 
@@ -310,16 +311,21 @@ declare_class!(
                 self.ivars().ime_state.set(ImeState::Ground);
             }
 
-            // Empty string basically means that there's no preedit, so indicate that by sending
-            // `None` cursor range.
-            let cursor_range = if preedit_string.is_empty() {
+            let cursor_range = if string.is_empty() {
+                // An empty string basically means that there's no preedit, so indicate that by
+                // sending a `None` cursor range.
                 None
             } else {
-                Some((preedit_string.len(), preedit_string.len()))
+                // Convert the selected range from UTF-16 indices to UTF-8 indices.
+                let sub_string_a = unsafe { string.substringToIndex(selected_range.location) };
+                let sub_string_b = unsafe { string.substringToIndex(selected_range.end()) };
+                let lowerbound_utf8 = sub_string_a.len();
+                let upperbound_utf8 = sub_string_b.len();
+                Some((lowerbound_utf8, upperbound_utf8))
             };
 
             // Send WindowEvent for updating marked text
-            self.queue_event(WindowEvent::Ime(Ime::Preedit(preedit_string, cursor_range)));
+            self.queue_event(WindowEvent::Ime(Ime::Preedit(string.to_string(), cursor_range)));
         }
 
         #[method(unmarkText)]
@@ -379,6 +385,7 @@ declare_class!(
 
         #[method(insertText:replacementRange:)]
         fn insert_text(&self, string: &NSObject, _replacement_range: NSRange) {
+            // TODO: Use _replacement_range, requires changing the event to report surrounding text.
             trace_scope!("insertText:replacementRange:");
 
             // SAFETY: This method is guaranteed to get either a `NSString` or a `NSAttributedString`.
@@ -392,7 +399,7 @@ declare_class!(
                 unsafe { &*string }.to_string()
             };
 
-            let is_control = string.chars().next().map_or(false, |c| c.is_control());
+            let is_control = string.chars().next().is_some_and(|c| c.is_control());
 
             // Commit only if we have marked text.
             if unsafe { self.hasMarkedText() } && self.is_ime_enabled() && !is_control {
@@ -475,7 +482,7 @@ declare_class!(
             };
 
             if !had_ime_input || self.ivars().forward_key_to_app.get() {
-                let key_event = create_key_event(&event, true, unsafe { event.isARepeat() }, None);
+                let key_event = create_key_event(&event, true, unsafe { event.isARepeat() });
                 self.queue_event(WindowEvent::KeyboardInput {
                     device_id: DEVICE_ID,
                     event: key_event,
@@ -498,7 +505,7 @@ declare_class!(
             ) {
                 self.queue_event(WindowEvent::KeyboardInput {
                     device_id: DEVICE_ID,
-                    event: create_key_event(&event, false, false, None),
+                    event: create_key_event(&event, false, false),
                     is_synthetic: false,
                 });
             }
@@ -545,7 +552,7 @@ declare_class!(
                 .expect("could not find current event");
 
             self.update_modifiers(&event, false);
-            let event = create_key_event(&event, true, unsafe { event.isARepeat() }, None);
+            let event = create_key_event(&event, true, unsafe { event.isARepeat() });
 
             self.queue_event(WindowEvent::KeyboardInput {
                 device_id: DEVICE_ID,
@@ -679,7 +686,7 @@ declare_class!(
 
             self.update_modifiers(event, false);
 
-            self.queue_device_event(DeviceEvent::MouseWheel { delta });
+            self.ivars().app_delegate.maybe_queue_device_event(DeviceEvent::MouseWheel { delta });
             self.queue_event(WindowEvent::MouseWheel {
                 device_id: DEVICE_ID,
                 delta,
@@ -823,11 +830,7 @@ impl WinitView {
     }
 
     fn queue_event(&self, event: WindowEvent) {
-        self.ivars().app_delegate.queue_window_event(self.window().id(), event);
-    }
-
-    fn queue_device_event(&self, event: DeviceEvent) {
-        self.ivars().app_delegate.queue_device_event(event);
+        self.ivars().app_delegate.maybe_queue_window_event(self.window().id(), event);
     }
 
     fn scale_factor(&self) -> f64 {
@@ -930,22 +933,36 @@ impl WinitView {
                 let scancode = unsafe { ns_event.keyCode() };
                 let physical_key = scancode_to_physicalkey(scancode as u32);
 
-                // We'll correct the `is_press` later.
-                let mut event = create_key_event(ns_event, false, false, Some(physical_key));
-
-                let key = code_to_key(physical_key, scancode);
+                let logical_key = code_to_key(physical_key, scancode);
                 // Ignore processing of unknown modifiers because we can't determine whether
                 // it was pressed or release reliably.
-                let Some(event_modifier) = key_to_modifier(&key) else {
+                //
+                // Furthermore, sometimes normal keys are reported inside flagsChanged:, such as
+                // when holding Caps Lock while pressing another key, see:
+                // https://github.com/alacritty/alacritty/issues/8268
+                let Some(event_modifier) = key_to_modifier(&logical_key) else {
                     break 'send_event;
                 };
-                event.physical_key = physical_key;
-                event.logical_key = key.clone();
-                event.location = code_to_location(physical_key);
+
+                let mut event = KeyEvent {
+                    location: code_to_location(physical_key),
+                    logical_key: logical_key.clone(),
+                    physical_key,
+                    repeat: false,
+                    // We'll correct this later.
+                    state: Pressed,
+                    text: None,
+                    platform_specific: KeyEventExtra {
+                        text_with_all_modifiers: None,
+                        key_without_modifiers: logical_key.clone(),
+                    },
+                };
+
                 let location_mask = ModLocationMask::from_location(event.location);
 
                 let mut phys_mod_state = self.ivars().phys_modifiers.borrow_mut();
-                let phys_mod = phys_mod_state.entry(key).or_insert(ModLocationMask::empty());
+                let phys_mod =
+                    phys_mod_state.entry(logical_key).or_insert(ModLocationMask::empty());
 
                 let is_active = current_modifiers.state().contains(event_modifier);
                 let mut events = VecDeque::with_capacity(2);

src/platform_impl/macos/window.rs

@@ -74,7 +74,7 @@ impl Window {
 pub struct WindowId(pub usize);
 
 impl WindowId {
-    pub const unsafe fn dummy() -> Self {
+    pub const fn dummy() -> Self {
         Self(0)
     }
 }

src/platform_impl/macos/window_delegate.rs

@@ -1,6 +1,9 @@
 #![allow(clippy::unnecessary_cast)]
 use std::cell::{Cell, RefCell};
 use std::collections::VecDeque;
+use std::ffi::c_void;
+use std::ptr;
+use std::sync::{Arc, Mutex};
 
 use core_graphics::display::{CGDisplay, CGPoint};
 use monitor::VideoModeHandle;
@@ -8,28 +11,31 @@ use objc2::rc::{autoreleasepool, Retained};
 use objc2::runtime::{AnyObject, ProtocolObject};
 use objc2::{declare_class, msg_send_id, mutability, sel, ClassType, DeclaredClass};
 use objc2_app_kit::{
-    NSAppKitVersionNumber, NSAppKitVersionNumber10_12, NSAppearance, NSApplication,
-    NSApplicationPresentationOptions, NSBackingStoreType, NSDraggingDestination,
-    NSFilenamesPboardType, NSPasteboard, NSRequestUserAttentionType, NSScreen, NSView,
-    NSWindowButton, NSWindowDelegate, NSWindowFullScreenButton, NSWindowLevel,
-    NSWindowOcclusionState, NSWindowOrderingMode, NSWindowSharingType, NSWindowStyleMask,
-    NSWindowTabbingMode, NSWindowTitleVisibility,
+    NSAppKitVersionNumber, NSAppKitVersionNumber10_12, NSAppearance, NSAppearanceCustomization,
+    NSAppearanceNameAqua, NSApplication, NSApplicationPresentationOptions, NSBackingStoreType,
+    NSColor, NSDraggingDestination, NSFilenamesPboardType, NSPasteboard,
+    NSRequestUserAttentionType, NSScreen, NSView, NSWindowButton, NSWindowDelegate,
+    NSWindowFullScreenButton, NSWindowLevel, NSWindowOcclusionState, NSWindowOrderingMode,
+    NSWindowSharingType, NSWindowStyleMask, NSWindowTabbingMode, NSWindowTitleVisibility,
 };
 use objc2_foundation::{
-    ns_string, CGFloat, MainThreadMarker, NSArray, NSCopying, NSDistributedNotificationCenter,
-    NSObject, NSObjectNSDelayedPerforming, NSObjectNSThreadPerformAdditions, NSObjectProtocol,
-    NSPoint, NSRect, NSSize, NSString,
+    ns_string, CGFloat, MainThreadMarker, NSArray, NSCopying, NSDictionary, NSKeyValueChangeKey,
+    NSKeyValueChangeNewKey, NSKeyValueChangeOldKey, NSKeyValueObservingOptions, NSObject,
+    NSObjectNSDelayedPerforming, NSObjectNSKeyValueObserverRegistration, NSObjectProtocol, NSPoint,
+    NSRect, NSSize, NSString,
 };
+use tracing::{trace, warn};
 
-use super::app_delegate::ApplicationDelegate;
+use super::app_state::ApplicationDelegate;
 use super::cursor::cursor_from_icon;
 use super::monitor::{self, flip_window_screen_coordinates, get_display_id};
+use super::observer::RunLoop;
 use super::view::WinitView;
 use super::window::WinitWindow;
 use super::{ffi, Fullscreen, MonitorHandle, OsError, WindowId};
 use crate::dpi::{LogicalPosition, LogicalSize, PhysicalPosition, PhysicalSize, Position, Size};
 use crate::error::{ExternalError, NotSupportedError, OsError as RootOsError};
-use crate::event::WindowEvent;
+use crate::event::{InnerSizeWriter, WindowEvent};
 use crate::platform::macos::{OptionAsAlt, WindowExtMacOS};
 use crate::window::{
     Cursor, CursorGrabMode, Icon, ImePurpose, ResizeDirection, Theme, UserAttentionType,
@@ -49,6 +55,7 @@ pub struct PlatformSpecificWindowAttributes {
     pub accepts_first_mouse: bool,
     pub tabbing_identifier: Option<String>,
     pub option_as_alt: OptionAsAlt,
+    pub borderless_game: bool,
 }
 
 impl Default for PlatformSpecificWindowAttributes {
@@ -66,6 +73,7 @@ impl Default for PlatformSpecificWindowAttributes {
             accepts_first_mouse: true,
             tabbing_identifier: None,
             option_as_alt: Default::default(),
+            borderless_game: false,
         }
     }
 }
@@ -77,12 +85,10 @@ pub(crate) struct State {
 
     window: Retained<WinitWindow>,
 
-    current_theme: Cell<Option<Theme>>,
-
     // During `windowDidResize`, we use this to only send Moved if the position changed.
     //
-    // This is expressed in native screen coordinates.
-    previous_position: Cell<Option<NSPoint>>,
+    // This is expressed in desktop coordinates, and flipped to match Winit's coordinate system.
+    previous_position: Cell<NSPoint>,
 
     // Used to prevent redundant events.
     previous_scale_factor: Cell<f64>,
@@ -116,6 +122,7 @@ pub(crate) struct State {
     standard_frame: Cell<Option<NSRect>>,
     is_simple_fullscreen: Cell<bool>,
     saved_style: Cell<Option<NSWindowStyleMask>>,
+    is_borderless_game: Cell<bool>,
 }
 
 declare_class!(
@@ -184,7 +191,17 @@ declare_class!(
         #[method(windowDidChangeBackingProperties:)]
         fn window_did_change_backing_properties(&self, _: Option<&AnyObject>) {
             trace_scope!("windowDidChangeBackingProperties:");
-            self.queue_static_scale_factor_changed_event();
+            let scale_factor = self.scale_factor();
+            if scale_factor == self.ivars().previous_scale_factor.get() {
+                return;
+            };
+            self.ivars().previous_scale_factor.set(scale_factor);
+
+            let mtm = MainThreadMarker::from(self);
+            let this = self.retain();
+            RunLoop::main(mtm).queue_closure(move || {
+                this.handle_scale_factor_changed(scale_factor);
+            });
         }
 
         #[method(windowDidBecomeKey:)]
@@ -407,32 +424,66 @@ declare_class!(
         }
     }
 
+    // Key-Value Observing
     unsafe impl WindowDelegate {
-        // Observe theme change
-        #[method(effectiveAppearanceDidChange:)]
-        fn effective_appearance_did_change(&self, sender: Option<&AnyObject>) {
-            trace_scope!("effectiveAppearanceDidChange:");
-            unsafe {
-                self.performSelectorOnMainThread_withObject_waitUntilDone(
-                    sel!(effectiveAppearanceDidChangedOnMainThread:),
-                    sender,
-                    false,
-                )
-            };
-        }
+        #[method(observeValueForKeyPath:ofObject:change:context:)]
+        fn observe_value(
+            &self,
+            key_path: Option<&NSString>,
+            _object: Option<&AnyObject>,
+            change: Option<&NSDictionary<NSKeyValueChangeKey, AnyObject>>,
+            _context: *mut c_void,
+        ) {
+            trace_scope!("observeValueForKeyPath:ofObject:change:context:");
+            // NOTE: We don't _really_ need to check the key path, as there should only be one, but
+            // in the future we might want to observe other key paths.
+            if key_path == Some(ns_string!("effectiveAppearance")) {
+                let change = change.expect("requested a change dictionary in `addObserver`, but none was provided");
+                let old = change.get(unsafe { NSKeyValueChangeOldKey }).expect("requested change dictionary did not contain `NSKeyValueChangeOldKey`");
+                let new = change.get(unsafe { NSKeyValueChangeNewKey }).expect("requested change dictionary did not contain `NSKeyValueChangeNewKey`");
 
-        #[method(effectiveAppearanceDidChangedOnMainThread:)]
-        fn effective_appearance_did_changed_on_main_thread(&self, _: Option<&AnyObject>) {
-            let mtm = MainThreadMarker::from(self);
-            let theme = get_ns_theme(mtm);
-            let old_theme = self.ivars().current_theme.replace(Some(theme));
-            if old_theme != Some(theme) {
-                self.queue_event(WindowEvent::ThemeChanged(theme));
+                // SAFETY: The value of `effectiveAppearance` is `NSAppearance`
+                let old: *const AnyObject = old;
+                let old: *const NSAppearance = old.cast();
+                let old: &NSAppearance = unsafe { &*old };
+                let new: *const AnyObject = new;
+                let new: *const NSAppearance = new.cast();
+                let new: &NSAppearance = unsafe { &*new };
+
+                trace!(old = %unsafe { old.name() }, new = %unsafe { new.name() }, "effectiveAppearance changed");
+
+                // Ignore the change if the window's theme is customized by the user (since in that
+                // case the `effectiveAppearance` is only emitted upon said customization, and then
+                // it's triggered directly by a user action, and we don't want to emit the event).
+                if unsafe { self.window().appearance() }.is_some() {
+                    return;
+                }
+
+                let old = appearance_to_theme(old);
+                let new = appearance_to_theme(new);
+                // Check that the theme changed in Winit's terms (the theme might have changed on
+                // other parameters, such as level of contrast, but the event should not be emitted
+                // in those cases).
+                if old == new {
+                    return;
+                }
+
+                self.queue_event(WindowEvent::ThemeChanged(new));
+            } else {
+                panic!("unknown observed keypath {key_path:?}");
             }
         }
     }
 );
 
+impl Drop for WindowDelegate {
+    fn drop(&mut self) {
+        unsafe {
+            self.window().removeObserver_forKeyPath(self, ns_string!("effectiveAppearance"));
+        }
+    }
+}
+
 fn new_window(
     app_delegate: &ApplicationDelegate,
     attrs: &WindowAttributes,
@@ -601,6 +652,8 @@ fn new_window(
 
         if attrs.transparent {
             window.setOpaque(false);
+            // See `set_transparent` for details on why we do this.
+            window.setBackgroundColor(unsafe { Some(&NSColor::clearColor()) });
         }
 
         // register for drag and drop operations.
@@ -654,16 +707,14 @@ impl WindowDelegate {
 
         let scale_factor = window.backingScaleFactor() as _;
 
-        let current_theme = match attrs.preferred_theme {
-            Some(theme) => Some(theme),
-            None => Some(get_ns_theme(mtm)),
-        };
+        if let Some(appearance) = theme_to_appearance(attrs.preferred_theme) {
+            unsafe { window.setAppearance(Some(&appearance)) };
+        }
 
         let delegate = mtm.alloc().set_ivars(State {
             app_delegate: app_delegate.retain(),
             window: window.retain(),
-            current_theme: Cell::new(current_theme),
-            previous_position: Cell::new(None),
+            previous_position: Cell::new(flip_window_screen_coordinates(window.frame())),
             previous_scale_factor: Cell::new(scale_factor),
             resize_increments: Cell::new(resize_increments),
             decorations: Cell::new(attrs.decorations),
@@ -677,22 +728,28 @@ impl WindowDelegate {
             standard_frame: Cell::new(None),
             is_simple_fullscreen: Cell::new(false),
             saved_style: Cell::new(None),
+            is_borderless_game: Cell::new(attrs.platform_specific.borderless_game),
         });
         let delegate: Retained<WindowDelegate> = unsafe { msg_send_id![super(delegate), init] };
 
         if scale_factor != 1.0 {
-            delegate.queue_static_scale_factor_changed_event();
+            let delegate = delegate.clone();
+            RunLoop::main(mtm).queue_closure(move || {
+                delegate.handle_scale_factor_changed(scale_factor);
+            });
         }
         window.setDelegate(Some(ProtocolObject::from_ref(&*delegate)));
 
-        // Enable theme change event
-        let notification_center = unsafe { NSDistributedNotificationCenter::defaultCenter() };
+        // Listen for theme change event.
+        //
+        // SAFETY: The observer is un-registered in the `Drop` of the delegate.
         unsafe {
-            notification_center.addObserver_selector_name_object(
+            window.addObserver_forKeyPath_options_context(
                 &delegate,
-                sel!(effectiveAppearanceDidChange:),
-                Some(ns_string!("AppleInterfaceThemeChangedNotification")),
-                None,
+                ns_string!("effectiveAppearance"),
+                NSKeyValueObservingOptions::NSKeyValueObservingOptionNew
+                    | NSKeyValueObservingOptions::NSKeyValueObservingOptionOld,
+                ptr::null_mut(),
             )
         };
 
@@ -754,34 +811,40 @@ impl WindowDelegate {
     }
 
     pub(crate) fn queue_event(&self, event: WindowEvent) {
-        self.ivars().app_delegate.queue_window_event(self.window().id(), event);
+        self.ivars().app_delegate.maybe_queue_window_event(self.window().id(), event);
     }
 
-    fn queue_static_scale_factor_changed_event(&self) {
-        let scale_factor = self.scale_factor();
-        if scale_factor == self.ivars().previous_scale_factor.get() {
-            return;
-        };
+    fn handle_scale_factor_changed(&self, scale_factor: CGFloat) {
+        let app_delegate = &self.ivars().app_delegate;
+        let window = self.window();
 
-        self.ivars().previous_scale_factor.set(scale_factor);
-        let content_size = self.window().contentRectForFrameRect(self.window().frame()).size;
+        let content_size = window.contentRectForFrameRect(window.frame()).size;
         let content_size = LogicalSize::new(content_size.width, content_size.height);
 
-        self.ivars().app_delegate.queue_static_scale_factor_changed_event(
-            self.window().retain(),
-            content_size.to_physical(scale_factor),
+        let suggested_size = content_size.to_physical(scale_factor);
+        let new_inner_size = Arc::new(Mutex::new(suggested_size));
+        app_delegate.handle_window_event(window.id(), WindowEvent::ScaleFactorChanged {
             scale_factor,
-        );
+            inner_size_writer: InnerSizeWriter::new(Arc::downgrade(&new_inner_size)),
+        });
+        let physical_size = *new_inner_size.lock().unwrap();
+        drop(new_inner_size);
+
+        if physical_size != suggested_size {
+            let logical_size = physical_size.to_logical(scale_factor);
+            let size = NSSize::new(logical_size.width, logical_size.height);
+            window.setContentSize(size);
+        }
+        app_delegate.handle_window_event(window.id(), WindowEvent::Resized(physical_size));
     }
 
     fn emit_move_event(&self) {
-        let frame = self.window().frame();
-        if self.ivars().previous_position.get() == Some(frame.origin) {
+        let position = flip_window_screen_coordinates(self.window().frame());
+        if self.ivars().previous_position.get() == position {
             return;
         }
-        self.ivars().previous_position.set(Some(frame.origin));
+        self.ivars().previous_position.set(position);
 
-        let position = flip_window_screen_coordinates(frame);
         let position =
             LogicalPosition::new(position.x, position.y).to_physical(self.scale_factor());
         self.queue_event(WindowEvent::Moved(position));
@@ -799,7 +862,23 @@ impl WindowDelegate {
     }
 
     pub fn set_transparent(&self, transparent: bool) {
-        self.window().setOpaque(!transparent)
+        // This is just a hint for Quartz, it doesn't actually speculate with window alpha.
+        // Providing a wrong value here could result in visual artifacts, when the window is
+        // transparent.
+        self.window().setOpaque(!transparent);
+
+        // AppKit draws the window with a background color by default, which is usually really
+        // nice, but gets in the way when we want to allow the contents of the window to be
+        // transparent, as in that case, the transparent contents will just be drawn on top of
+        // the background color. As such, to allow the window to be transparent, we must also set
+        // the background color to one with an empty alpha channel.
+        let color = if transparent {
+            unsafe { NSColor::clearColor() }
+        } else {
+            unsafe { NSColor::windowBackgroundColor() }
+        };
+
+        self.window().setBackgroundColor(Some(&color));
     }
 
     pub fn set_blur(&self, blur: bool) {
@@ -898,8 +977,8 @@ impl WindowDelegate {
 
     pub fn set_max_inner_size(&self, dimensions: Option<Size>) {
         let dimensions = dimensions.unwrap_or(Size::Logical(LogicalSize {
-            width: std::f32::MAX as f64,
-            height: std::f32::MAX as f64,
+            width: f32::MAX as f64,
+            height: f32::MAX as f64,
         }));
         let scale_factor = self.scale_factor();
         let max_size = dimensions.to_logical::<CGFloat>(scale_factor);
@@ -1084,7 +1163,8 @@ impl WindowDelegate {
     #[inline]
     pub fn drag_window(&self) -> Result<(), ExternalError> {
         let mtm = MainThreadMarker::from(self);
-        let event = NSApplication::sharedApplication(mtm).currentEvent().unwrap();
+        let event =
+            NSApplication::sharedApplication(mtm).currentEvent().ok_or(ExternalError::Ignored)?;
         self.window().performWindowDragWithEvent(&event);
         Ok(())
     }
@@ -1333,7 +1413,7 @@ impl WindowDelegate {
         }
 
         match (old_fullscreen, fullscreen) {
-            (None, Some(_)) => {
+            (None, Some(fullscreen)) => {
                 // `toggleFullScreen` doesn't work if the `StyleMask` is none, so we
                 // set a normal style temporarily. The previous state will be
                 // restored in `WindowDelegate::window_did_exit_fullscreen`.
@@ -1343,6 +1423,17 @@ impl WindowDelegate {
                     self.set_style_mask(required);
                     self.ivars().saved_style.set(Some(curr_mask));
                 }
+
+                // In borderless games, we want to disable the dock and menu bar
+                // by setting the presentation options. We do this here rather than in
+                // `window:willUseFullScreenPresentationOptions` because for some reason
+                // the menu bar remains interactable despite being hidden.
+                if self.is_borderless_game() && matches!(fullscreen, Fullscreen::Borderless(_)) {
+                    let presentation_options = NSApplicationPresentationOptions::NSApplicationPresentationHideDock
+                            | NSApplicationPresentationOptions::NSApplicationPresentationHideMenuBar;
+                    app.setPresentationOptions(presentation_options);
+                }
+
                 toggle_fullscreen(self.window());
             },
             (Some(Fullscreen::Borderless(_)), None) => {
@@ -1350,13 +1441,7 @@ impl WindowDelegate {
                 toggle_fullscreen(self.window());
             },
             (Some(Fullscreen::Exclusive(ref video_mode)), None) => {
-                unsafe {
-                    ffi::CGRestorePermanentDisplayConfiguration();
-                    assert_eq!(
-                        ffi::CGDisplayRelease(video_mode.monitor().native_identifier()),
-                        ffi::kCGErrorSuccess
-                    );
-                };
+                restore_and_release_display(&video_mode.monitor());
                 toggle_fullscreen(self.window());
             },
             (Some(Fullscreen::Borderless(_)), Some(Fullscreen::Exclusive(_))) => {
@@ -1387,13 +1472,7 @@ impl WindowDelegate {
                 );
                 app.setPresentationOptions(presentation_options);
 
-                unsafe {
-                    ffi::CGRestorePermanentDisplayConfiguration();
-                    assert_eq!(
-                        ffi::CGDisplayRelease(video_mode.monitor().native_identifier()),
-                        ffi::kCGErrorSuccess
-                    );
-                };
+                restore_and_release_display(&video_mode.monitor());
 
                 // Restore the normal window level following the Borderless fullscreen
                 // `CGShieldingWindowLevel() + 1` hack.
@@ -1513,7 +1592,14 @@ impl WindowDelegate {
     // Allow directly accessing the current monitor internally without unwrapping.
     pub(crate) fn current_monitor_inner(&self) -> Option<MonitorHandle> {
         let display_id = get_display_id(&*self.window().screen()?);
-        Some(MonitorHandle::new(display_id))
+        if let Some(monitor) = MonitorHandle::new(display_id) {
+            Some(monitor)
+        } else {
+            // NOTE: Display ID was just fetched from live NSScreen, but can still result in `None`
+            // with certain Thunderbolt docked monitors.
+            warn!(display_id, "got screen with invalid display ID");
+            None
+        }
     }
 
     #[inline]
@@ -1537,7 +1623,7 @@ impl WindowDelegate {
     pub fn raw_window_handle_rwh_04(&self) -> rwh_04::RawWindowHandle {
         let mut window_handle = rwh_04::AppKitHandle::empty();
         window_handle.ns_window = self.window() as *const WinitWindow as *mut _;
-        window_handle.ns_view = Retained::as_ptr(&self.contentView().unwrap()) as *mut _;
+        window_handle.ns_view = Retained::as_ptr(&self.view()) as *mut _;
         rwh_04::RawWindowHandle::AppKit(window_handle)
     }
 
@@ -1575,20 +1661,28 @@ impl WindowDelegate {
         }
     }
 
-    #[inline]
-    pub fn theme(&self) -> Option<Theme> {
-        self.ivars().current_theme.get()
-    }
-
     #[inline]
     pub fn has_focus(&self) -> bool {
         self.window().isKeyWindow()
     }
 
+    pub fn theme(&self) -> Option<Theme> {
+        unsafe { self.window().appearance() }
+            .map(|appearance| appearance_to_theme(&appearance))
+            .or_else(|| {
+                let mtm = MainThreadMarker::from(self);
+                let app = NSApplication::sharedApplication(mtm);
+
+                if app.respondsToSelector(sel!(effectiveAppearance)) {
+                    Some(super::window_delegate::appearance_to_theme(&app.effectiveAppearance()))
+                } else {
+                    Some(Theme::Light)
+                }
+            })
+    }
+
     pub fn set_theme(&self, theme: Option<Theme>) {
-        let mtm = MainThreadMarker::from(self);
-        set_ns_theme(theme, mtm);
-        self.ivars().current_theme.set(theme.or_else(|| Some(get_ns_theme(mtm))));
+        unsafe { self.window().setAppearance(theme_to_appearance(theme).as_deref()) };
     }
 
     #[inline]
@@ -1609,6 +1703,21 @@ impl WindowDelegate {
     }
 }
 
+fn restore_and_release_display(monitor: &MonitorHandle) {
+    let available_monitors = monitor::available_monitors();
+    if available_monitors.contains(monitor) {
+        unsafe {
+            ffi::CGRestorePermanentDisplayConfiguration();
+            assert_eq!(ffi::CGDisplayRelease(monitor.native_identifier()), ffi::kCGErrorSuccess);
+        };
+    } else {
+        warn!(
+            monitor = monitor.name(),
+            "Tried to restore exclusive fullscreen on a monitor that is no longer available"
+        );
+    }
+}
+
 impl WindowExtMacOS for WindowDelegate {
     #[inline]
     fn simple_fullscreen(&self) -> bool {
@@ -1644,9 +1753,13 @@ impl WindowExtMacOS for WindowDelegate {
             self.ivars().is_simple_fullscreen.set(true);
 
             // Simulate pre-Lion fullscreen by hiding the dock and menu bar
-            let presentation_options =
+            let presentation_options = if self.is_borderless_game() {
+                NSApplicationPresentationOptions::NSApplicationPresentationHideDock
+                    | NSApplicationPresentationOptions::NSApplicationPresentationHideMenuBar
+            } else {
                 NSApplicationPresentationOptions::NSApplicationPresentationAutoHideDock
-                    | NSApplicationPresentationOptions::NSApplicationPresentationAutoHideMenuBar;
+                    | NSApplicationPresentationOptions::NSApplicationPresentationAutoHideMenuBar
+            };
             app.setPresentationOptions(presentation_options);
 
             // Hide the titlebar
@@ -1660,11 +1773,8 @@ impl WindowExtMacOS for WindowDelegate {
             self.toggle_style_mask(NSWindowStyleMask::Miniaturizable, false);
             self.toggle_style_mask(NSWindowStyleMask::Resizable, false);
             self.window().setMovable(false);
-
-            true
         } else {
             let new_mask = self.saved_style();
-            self.set_style_mask(new_mask);
             self.ivars().is_simple_fullscreen.set(false);
 
             let save_presentation_opts = self.ivars().save_presentation_opts.get();
@@ -1676,9 +1786,10 @@ impl WindowExtMacOS for WindowDelegate {
 
             self.window().setFrame_display(frame, true);
             self.window().setMovable(true);
-
-            true
+            self.set_style_mask(new_mask);
         }
+
+        true
     }
 
     #[inline]
@@ -1742,39 +1853,52 @@ impl WindowExtMacOS for WindowDelegate {
     fn option_as_alt(&self) -> OptionAsAlt {
         self.view().option_as_alt()
     }
+
+    fn set_borderless_game(&self, borderless_game: bool) {
+        self.ivars().is_borderless_game.set(borderless_game);
+    }
+
+    fn is_borderless_game(&self) -> bool {
+        self.ivars().is_borderless_game.get()
+    }
 }
 
 const DEFAULT_STANDARD_FRAME: NSRect =
     NSRect::new(NSPoint::new(50.0, 50.0), NSSize::new(800.0, 600.0));
 
-pub(super) fn get_ns_theme(mtm: MainThreadMarker) -> Theme {
-    let app = NSApplication::sharedApplication(mtm);
-    if !app.respondsToSelector(sel!(effectiveAppearance)) {
-        return Theme::Light;
-    }
-    let appearance = app.effectiveAppearance();
-    let name = appearance
-        .bestMatchFromAppearancesWithNames(&NSArray::from_id_slice(&[
-            NSString::from_str("NSAppearanceNameAqua"),
-            NSString::from_str("NSAppearanceNameDarkAqua"),
-        ]))
-        .unwrap();
-    match &*name.to_string() {
-        "NSAppearanceNameDarkAqua" => Theme::Dark,
-        _ => Theme::Light,
+fn dark_appearance_name() -> &'static NSString {
+    // Don't use the static `NSAppearanceNameDarkAqua` to allow linking on macOS < 10.14
+    ns_string!("NSAppearanceNameDarkAqua")
+}
+
+pub fn appearance_to_theme(appearance: &NSAppearance) -> Theme {
+    let best_match = appearance.bestMatchFromAppearancesWithNames(&NSArray::from_id_slice(&[
+        unsafe { NSAppearanceNameAqua.copy() },
+        dark_appearance_name().copy(),
+    ]));
+    if let Some(best_match) = best_match {
+        if *best_match == *dark_appearance_name() {
+            Theme::Dark
+        } else {
+            Theme::Light
+        }
+    } else {
+        warn!(?appearance, "failed to determine the theme of the appearance");
+        // Default to light in this case
+        Theme::Light
     }
 }
 
-fn set_ns_theme(theme: Option<Theme>, mtm: MainThreadMarker) {
-    let app = NSApplication::sharedApplication(mtm);
-    if app.respondsToSelector(sel!(effectiveAppearance)) {
-        let appearance = theme.map(|t| {
-            let name = match t {
-                Theme::Dark => NSString::from_str("NSAppearanceNameDarkAqua"),
-                Theme::Light => NSString::from_str("NSAppearanceNameAqua"),
-            };
-            NSAppearance::appearanceNamed(&name).unwrap()
-        });
-        app.setAppearance(appearance.as_ref().map(|a| a.as_ref()));
+fn theme_to_appearance(theme: Option<Theme>) -> Option<Retained<NSAppearance>> {
+    let appearance = match theme? {
+        Theme::Light => unsafe { NSAppearance::appearanceNamed(NSAppearanceNameAqua) },
+        Theme::Dark => NSAppearance::appearanceNamed(dark_appearance_name()),
+    };
+    if let Some(appearance) = appearance {
+        Some(appearance)
+    } else {
+        warn!(?theme, "could not find appearance for theme");
+        // Assume system appearance in this case
+        None
     }
 }

src/platform_impl/mod.rs

@@ -1,27 +1,35 @@
 use crate::monitor::{MonitorHandle as RootMonitorHandle, VideoModeHandle as RootVideoModeHandle};
 use crate::window::Fullscreen as RootFullscreen;
 
-#[cfg(windows_platform)]
-#[path = "windows/mod.rs"]
-mod platform;
-#[cfg(any(x11_platform, wayland_platform))]
-#[path = "linux/mod.rs"]
-mod platform;
-#[cfg(macos_platform)]
-#[path = "macos/mod.rs"]
-mod platform;
 #[cfg(android_platform)]
-#[path = "android/mod.rs"]
-mod platform;
+mod android;
 #[cfg(ios_platform)]
-#[path = "ios/mod.rs"]
-mod platform;
-#[cfg(web_platform)]
-#[path = "web/mod.rs"]
-mod platform;
+mod ios;
+#[cfg(any(x11_platform, wayland_platform))]
+mod linux;
+#[cfg(macos_platform)]
+mod macos;
 #[cfg(orbital_platform)]
-#[path = "orbital/mod.rs"]
-mod platform;
+mod orbital;
+#[cfg(web_platform)]
+mod web;
+#[cfg(windows_platform)]
+mod windows;
+
+#[cfg(android_platform)]
+use android as platform;
+#[cfg(ios_platform)]
+use ios as platform;
+#[cfg(any(x11_platform, wayland_platform))]
+use linux as platform;
+#[cfg(macos_platform)]
+use macos as platform;
+#[cfg(orbital_platform)]
+use orbital as platform;
+#[cfg(web_platform)]
+use web as platform;
+#[cfg(windows_platform)]
+use windows as platform;
 
 pub use self::platform::*;
 

src/platform_impl/orbital/event_loop.rs

@@ -12,7 +12,6 @@ use orbclient::{
 };
 use smol_str::SmolStr;
 
-use crate::application::ApplicationHandler;
 use crate::error::EventLoopError;
 use crate::event::{self, Ime, Modifiers, StartCause};
 use crate::event_loop::{self, ControlFlow, DeviceEvents};
@@ -21,7 +20,7 @@ use crate::keyboard::{
     PhysicalKey,
 };
 use crate::window::{
-    CustomCursor as RootCustomCursor, CustomCursorSource, WindowId as RootWindowId,
+    CustomCursor as RootCustomCursor, CustomCursorSource, Theme, WindowId as RootWindowId,
 };
 
 use super::{
@@ -323,13 +322,14 @@ impl<T: 'static> EventLoop<T> {
         })
     }
 
-    fn process_event<A: ApplicationHandler<T>>(
+    fn process_event<F>(
         window_id: WindowId,
         event_option: EventOption,
         event_state: &mut EventState,
-        window_target: &event_loop::ActiveEventLoop,
-        app: &mut A,
-    ) {
+        mut event_handler: F,
+    ) where
+        F: FnMut(event::Event<T>),
+    {
         match event_option {
             EventOption::Key(KeyEvent { character, scancode, pressed }) => {
                 // Convert scancode
@@ -371,128 +371,125 @@ impl<T: 'static> EventLoop<T> {
                     key_without_modifiers = logical_key.clone();
                 }
 
-                let window_id = RootWindowId(window_id);
-                let event = event::WindowEvent::KeyboardInput {
-                    device_id: event::DeviceId(DeviceId),
-                    event: event::KeyEvent {
-                        logical_key,
-                        physical_key,
-                        location: KeyLocation::Standard,
-                        state: element_state(pressed),
-                        repeat: false,
-                        text,
-                        platform_specific: KeyEventExtra {
-                            key_without_modifiers,
-                            text_with_all_modifiers,
+                event_handler(event::Event::WindowEvent {
+                    window_id: RootWindowId(window_id),
+                    event: event::WindowEvent::KeyboardInput {
+                        device_id: event::DeviceId(DeviceId),
+                        event: event::KeyEvent {
+                            logical_key,
+                            physical_key,
+                            location: KeyLocation::Standard,
+                            state: element_state(pressed),
+                            repeat: false,
+                            text,
+                            platform_specific: KeyEventExtra {
+                                key_without_modifiers,
+                                text_with_all_modifiers,
+                            },
                         },
+                        is_synthetic: false,
                     },
-                    is_synthetic: false,
-                };
-
-                app.window_event(window_target, window_id, event);
+                });
 
                 // If the state of the modifiers has changed, send the event.
                 if modifiers_before != event_state.keyboard {
-                    app.window_event(
-                        window_target,
-                        window_id,
-                        event::WindowEvent::ModifiersChanged(event_state.modifiers()),
-                    );
+                    event_handler(event::Event::WindowEvent {
+                        window_id: RootWindowId(window_id),
+                        event: event::WindowEvent::ModifiersChanged(event_state.modifiers()),
+                    })
                 }
             },
             EventOption::TextInput(TextInputEvent { character }) => {
-                app.window_event(
-                    window_target,
-                    RootWindowId(window_id),
-                    event::WindowEvent::Ime(Ime::Preedit("".into(), None)),
-                );
-                app.window_event(
-                    window_target,
-                    RootWindowId(window_id),
-                    event::WindowEvent::Ime(Ime::Commit(character.into())),
-                );
+                event_handler(event::Event::WindowEvent {
+                    window_id: RootWindowId(window_id),
+                    event: event::WindowEvent::Ime(Ime::Preedit("".into(), None)),
+                });
+                event_handler(event::Event::WindowEvent {
+                    window_id: RootWindowId(window_id),
+                    event: event::WindowEvent::Ime(Ime::Commit(character.into())),
+                });
             },
             EventOption::Mouse(MouseEvent { x, y }) => {
-                app.window_event(
-                    window_target,
-                    RootWindowId(window_id),
-                    event::WindowEvent::CursorMoved {
+                event_handler(event::Event::WindowEvent {
+                    window_id: RootWindowId(window_id),
+                    event: event::WindowEvent::CursorMoved {
                         device_id: event::DeviceId(DeviceId),
                         position: (x, y).into(),
                     },
-                );
+                });
             },
             EventOption::MouseRelative(MouseRelativeEvent { dx, dy }) => {
-                app.device_event(
-                    window_target,
-                    event::DeviceId(DeviceId),
-                    event::DeviceEvent::MouseMotion { delta: (dx as f64, dy as f64) },
-                );
+                event_handler(event::Event::DeviceEvent {
+                    device_id: event::DeviceId(DeviceId),
+                    event: event::DeviceEvent::MouseMotion { delta: (dx as f64, dy as f64) },
+                });
             },
             EventOption::Button(ButtonEvent { left, middle, right }) => {
                 while let Some((button, state)) = event_state.mouse(left, middle, right) {
-                    app.window_event(
-                        window_target,
-                        RootWindowId(window_id),
-                        event::WindowEvent::MouseInput {
+                    event_handler(event::Event::WindowEvent {
+                        window_id: RootWindowId(window_id),
+                        event: event::WindowEvent::MouseInput {
                             device_id: event::DeviceId(DeviceId),
                             state,
                             button,
                         },
-                    );
+                    });
                 }
             },
             EventOption::Scroll(ScrollEvent { x, y }) => {
-                app.window_event(
-                    window_target,
-                    RootWindowId(window_id),
-                    event::WindowEvent::MouseWheel {
+                event_handler(event::Event::WindowEvent {
+                    window_id: RootWindowId(window_id),
+                    event: event::WindowEvent::MouseWheel {
                         device_id: event::DeviceId(DeviceId),
                         delta: event::MouseScrollDelta::LineDelta(x as f32, y as f32),
                         phase: event::TouchPhase::Moved,
                     },
-                );
+                });
             },
             EventOption::Quit(QuitEvent {}) => {
-                app.window_event(
-                    window_target,
-                    RootWindowId(window_id),
-                    event::WindowEvent::CloseRequested,
-                );
+                event_handler(event::Event::WindowEvent {
+                    window_id: RootWindowId(window_id),
+                    event: event::WindowEvent::CloseRequested,
+                });
             },
             EventOption::Focus(FocusEvent { focused }) => {
-                app.window_event(
-                    window_target,
-                    RootWindowId(window_id),
-                    event::WindowEvent::Focused(focused),
-                );
+                event_handler(event::Event::WindowEvent {
+                    window_id: RootWindowId(window_id),
+                    event: event::WindowEvent::Focused(focused),
+                });
             },
             EventOption::Move(MoveEvent { x, y }) => {
-                app.window_event(
-                    window_target,
-                    RootWindowId(window_id),
-                    event::WindowEvent::Moved((x, y).into()),
-                );
+                event_handler(event::Event::WindowEvent {
+                    window_id: RootWindowId(window_id),
+                    event: event::WindowEvent::Moved((x, y).into()),
+                });
             },
             EventOption::Resize(ResizeEvent { width, height }) => {
-                app.window_event(
-                    window_target,
-                    RootWindowId(window_id),
-                    event::WindowEvent::Resized((width, height).into()),
-                );
+                event_handler(event::Event::WindowEvent {
+                    window_id: RootWindowId(window_id),
+                    event: event::WindowEvent::Resized((width, height).into()),
+                });
 
                 // Acknowledge resize after event loop.
                 event_state.resize_opt = Some((width, height));
             },
             // TODO: Screen, Clipboard, Drop
             EventOption::Hover(HoverEvent { entered }) => {
-                let event = if entered {
-                    event::WindowEvent::CursorEntered { device_id: event::DeviceId(DeviceId) }
+                if entered {
+                    event_handler(event::Event::WindowEvent {
+                        window_id: RootWindowId(window_id),
+                        event: event::WindowEvent::CursorEntered {
+                            device_id: event::DeviceId(DeviceId),
+                        },
+                    });
                 } else {
-                    event::WindowEvent::CursorLeft { device_id: event::DeviceId(DeviceId) }
-                };
-
-                app.window_event(window_target, RootWindowId(window_id), event);
+                    event_handler(event::Event::WindowEvent {
+                        window_id: RootWindowId(window_id),
+                        event: event::WindowEvent::CursorLeft {
+                            device_id: event::DeviceId(DeviceId),
+                        },
+                    });
+                }
             },
             other => {
                 tracing::warn!("unhandled event: {:?}", other);
@@ -500,13 +497,22 @@ impl<T: 'static> EventLoop<T> {
         }
     }
 
-    pub fn run_app<A: ApplicationHandler<T>>(mut self, app: &mut A) -> Result<(), EventLoopError> {
+    pub fn run<F>(mut self, mut event_handler_inner: F) -> Result<(), EventLoopError>
+    where
+        F: FnMut(event::Event<T>, &event_loop::ActiveEventLoop),
+    {
+        let mut event_handler =
+            move |event: event::Event<T>, window_target: &event_loop::ActiveEventLoop| {
+                event_handler_inner(event, window_target);
+            };
+
         let mut start_cause = StartCause::Init;
+
         loop {
-            app.new_events(&self.window_target, start_cause);
+            event_handler(event::Event::NewEvents(start_cause), &self.window_target);
 
             if start_cause == StartCause::Init {
-                app.resumed(&self.window_target);
+                event_handler(event::Event::Resumed, &self.window_target);
             }
 
             // Handle window creates.
@@ -522,15 +528,23 @@ impl<T: 'static> EventLoop<T> {
 
                 self.windows.push((window, EventState::default()));
 
-                let window_id = RootWindowId(window_id);
-
                 // Send resize event on create to indicate first size.
-                let event = event::WindowEvent::Resized((properties.w, properties.h).into());
-                app.window_event(&self.window_target, window_id, event);
+                event_handler(
+                    event::Event::WindowEvent {
+                        window_id: RootWindowId(window_id),
+                        event: event::WindowEvent::Resized((properties.w, properties.h).into()),
+                    },
+                    &self.window_target,
+                );
 
-                // Send moved event on create to indicate first position.
-                let event = event::WindowEvent::Moved((properties.x, properties.y).into());
-                app.window_event(&self.window_target, window_id, event);
+                // Send resize event on create to indicate first position.
+                event_handler(
+                    event::Event::WindowEvent {
+                        window_id: RootWindowId(window_id),
+                        event: event::WindowEvent::Moved((properties.x, properties.y).into()),
+                    },
+                    &self.window_target,
+                );
             }
 
             // Handle window destroys.
@@ -538,8 +552,14 @@ impl<T: 'static> EventLoop<T> {
                 let mut destroys = self.window_target.p.destroys.lock().unwrap();
                 destroys.pop_front()
             } {
-                let window_id = RootWindowId(destroy_id);
-                app.window_event(&self.window_target, window_id, event::WindowEvent::Destroyed);
+                event_handler(
+                    event::Event::WindowEvent {
+                        window_id: RootWindowId(destroy_id),
+                        event: event::WindowEvent::Destroyed,
+                    },
+                    &self.window_target,
+                );
+
                 self.windows.retain(|(window, _event_state)| window.fd as u64 != destroy_id.fd);
             }
 
@@ -566,8 +586,7 @@ impl<T: 'static> EventLoop<T> {
                         window_id,
                         orbital_event.to_option(),
                         event_state,
-                        &self.window_target,
-                        app,
+                        |event| event_handler(event, &self.window_target),
                     );
                 }
 
@@ -595,7 +614,7 @@ impl<T: 'static> EventLoop<T> {
             }
 
             while let Ok(event) = self.user_events_receiver.try_recv() {
-                app.user_event(&self.window_target, event);
+                event_handler(event::Event::UserEvent(event), &self.window_target);
             }
 
             // To avoid deadlocks the redraws lock is not held during event processing.
@@ -603,14 +622,16 @@ impl<T: 'static> EventLoop<T> {
                 let mut redraws = self.window_target.p.redraws.lock().unwrap();
                 redraws.pop_front()
             } {
-                app.window_event(
+                event_handler(
+                    event::Event::WindowEvent {
+                        window_id: RootWindowId(window_id),
+                        event: event::WindowEvent::RedrawRequested,
+                    },
                     &self.window_target,
-                    RootWindowId(window_id),
-                    event::WindowEvent::RedrawRequested,
                 );
             }
 
-            app.about_to_wait(&self.window_target);
+            event_handler(event::Event::AboutToWait, &self.window_target);
 
             if self.window_target.p.exiting() {
                 break;
@@ -674,7 +695,7 @@ impl<T: 'static> EventLoop<T> {
             }
         }
 
-        app.exiting(&self.window_target);
+        event_handler(event::Event::LoopExiting, &self.window_target);
 
         Ok(())
     }
@@ -754,6 +775,11 @@ impl ActiveEventLoop {
         rwh_05::RawDisplayHandle::Orbital(rwh_05::OrbitalDisplayHandle::empty())
     }
 
+    #[inline]
+    pub fn system_theme(&self) -> Option<Theme> {
+        None
+    }
+
     #[cfg(feature = "rwh_06")]
     #[inline]
     pub fn raw_display_handle_rwh_06(

src/platform_impl/orbital/mod.rs

@@ -103,7 +103,7 @@ pub struct WindowId {
 
 impl WindowId {
     pub const fn dummy() -> Self {
-        WindowId { fd: u64::max_value() }
+        WindowId { fd: u64::MAX }
     }
 }
 
@@ -154,7 +154,7 @@ impl<'a> WindowProperties<'a> {
     }
 }
 
-impl<'a> fmt::Display for WindowProperties<'a> {
+impl fmt::Display for WindowProperties<'_> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(
             f,

src/platform_impl/orbital/window.rs

@@ -420,7 +420,7 @@ impl Window {
             window::ResizeDirection::West => "L",
         };
         self.window_socket
-            .write(format!("D,{}", arg).as_bytes())
+            .write(format!("D,{arg}").as_bytes())
             .map_err(|err| error::ExternalError::Os(os_error!(OsError::new(err))))?;
         Ok(())
     }

src/platform_impl/web/async/channel.rs

@@ -23,7 +23,7 @@ pub struct Sender<T>(Arc<SenderInner<T>>);
 struct SenderInner<T> {
     // We need to wrap it into a `Mutex` to make it `Sync`. So the sender can't
     // be accessed on the main thread, as it could block. Additionally we need
-    // to wrap `Sender` in an `Arc` to make it clonable on the main thread without
+    // to wrap `Sender` in an `Arc` to make it cloneable on the main thread without
     // having to block.
     sender: Mutex<mpsc::Sender<T>>,
     shared: Arc<Shared>,

src/platform_impl/web/async/dispatcher.rs

@@ -68,7 +68,12 @@ impl<T> Dispatcher<T> {
             // SAFETY: The `transmute` is necessary because `Closure` requires `'static`. This is
             // safe because this function won't return until `f` has finished executing. See
             // `Self::new()`.
-            let closure = Closure(unsafe { std::mem::transmute(closure) });
+            let closure = Closure(unsafe {
+                std::mem::transmute::<
+                    Box<dyn FnOnce(&T) + Send>,
+                    Box<dyn FnOnce(&T) + Send + 'static>,
+                >(closure)
+            });
 
             self.0.send(closure);
 

src/platform_impl/web/async/waker.rs

@@ -1,4 +1,5 @@
 use std::future;
+use std::num::NonZeroUsize;
 use std::sync::atomic::{AtomicBool, AtomicUsize, Ordering};
 use std::sync::Arc;
 use std::task::Poll;
@@ -6,13 +7,13 @@ use std::task::Poll;
 use super::super::main_thread::MainThreadMarker;
 use super::{AtomicWaker, Wrapper};
 
-pub struct WakerSpawner<T: 'static>(Wrapper<Handler<T>, Sender, usize>);
+pub struct WakerSpawner<T: 'static>(Wrapper<Handler<T>, Sender, NonZeroUsize>);
 
-pub struct Waker<T: 'static>(Wrapper<Handler<T>, Sender, usize>);
+pub struct Waker<T: 'static>(Wrapper<Handler<T>, Sender, NonZeroUsize>);
 
 struct Handler<T> {
     value: T,
-    handler: fn(&T, usize),
+    handler: fn(&T, NonZeroUsize, bool),
 }
 
 #[derive(Clone)]
@@ -20,7 +21,11 @@ struct Sender(Arc<Inner>);
 
 impl<T> WakerSpawner<T> {
     #[track_caller]
-    pub fn new(main_thread: MainThreadMarker, value: T, handler: fn(&T, usize)) -> Option<Self> {
+    pub fn new(
+        main_thread: MainThreadMarker,
+        value: T,
+        handler: fn(&T, NonZeroUsize, bool),
+    ) -> Option<Self> {
         let inner = Arc::new(Inner {
             counter: AtomicUsize::new(0),
             waker: AtomicWaker::new(),
@@ -37,7 +42,7 @@ impl<T> WakerSpawner<T> {
             |handler, count| {
                 let handler = handler.borrow();
                 let handler = handler.as_ref().unwrap();
-                (handler.handler)(&handler.value, count);
+                (handler.handler)(&handler.value, count, true);
             },
             {
                 let inner = Arc::clone(&inner);
@@ -46,29 +51,31 @@ impl<T> WakerSpawner<T> {
                     while let Some(count) = future::poll_fn(|cx| {
                         let count = inner.counter.swap(0, Ordering::Relaxed);
 
-                        if count > 0 {
-                            Poll::Ready(Some(count))
-                        } else {
-                            inner.waker.register(cx.waker());
+                        match NonZeroUsize::new(count) {
+                            Some(count) => Poll::Ready(Some(count)),
+                            None => {
+                                inner.waker.register(cx.waker());
 
-                            let count = inner.counter.swap(0, Ordering::Relaxed);
+                                let count = inner.counter.swap(0, Ordering::Relaxed);
 
-                            if count > 0 {
-                                Poll::Ready(Some(count))
-                            } else {
-                                if inner.closed.load(Ordering::Relaxed) {
-                                    return Poll::Ready(None);
+                                match NonZeroUsize::new(count) {
+                                    Some(count) => Poll::Ready(Some(count)),
+                                    None => {
+                                        if inner.closed.load(Ordering::Relaxed) {
+                                            return Poll::Ready(None);
+                                        }
+
+                                        Poll::Pending
+                                    },
                                 }
-
-                                Poll::Pending
-                            }
+                            },
                         }
                     })
                     .await
                     {
                         let handler = handler.borrow();
                         let handler = handler.as_ref().unwrap();
-                        (handler.handler)(&handler.value, count);
+                        (handler.handler)(&handler.value, count, false);
                     }
                 }
             },
@@ -107,7 +114,7 @@ impl<T> Drop for WakerSpawner<T> {
 
 impl<T> Waker<T> {
     pub fn wake(&self) {
-        self.0.send(1)
+        self.0.send(NonZeroUsize::MIN)
     }
 }
 

src/platform_impl/web/cursor.rs

@@ -324,7 +324,11 @@ impl Inner {
             match &self.cursor {
                 SelectedCursor::Icon(icon)
                 | SelectedCursor::Loading { previous: Previous::Icon(icon), .. } => {
-                    self.style.set("cursor", icon.name())
+                    if let CursorIcon::Default = icon {
+                        self.style.remove("cursor")
+                    } else {
+                        self.style.set("cursor", icon.name())
+                    }
                 },
                 SelectedCursor::Loading { previous: Previous::Image(cursor), .. }
                 | SelectedCursor::Image(cursor) => {
@@ -538,8 +542,8 @@ fn from_rgba(
     //
     // We call `createImageBitmap()` before spawning the future,
     // to not have to clone the image buffer.
-    let mut options = ImageBitmapOptions::new();
-    options.premultiply_alpha(PremultiplyAlpha::None);
+    let options = ImageBitmapOptions::new();
+    options.set_premultiply_alpha(PremultiplyAlpha::None);
     let bitmap = JsFuture::from(
         window
             .create_image_bitmap_with_image_data_and_image_bitmap_options(&image_data, &options)

src/platform_impl/web/device.rs

@@ -2,7 +2,7 @@
 pub struct DeviceId(pub i32);
 
 impl DeviceId {
-    pub const unsafe fn dummy() -> Self {
+    pub const fn dummy() -> Self {
         Self(0)
     }
 }

src/platform_impl/web/event_loop/mod.rs

@@ -1,10 +1,10 @@
 use std::marker::PhantomData;
 use std::sync::mpsc::{self, Receiver, Sender};
 
-use crate::application::ApplicationHandler;
 use crate::error::EventLoopError;
 use crate::event::Event;
 use crate::event_loop::ActiveEventLoop as RootActiveEventLoop;
+use crate::platform::web::{ActiveEventLoopExtWebSys, PollStrategy, WaitUntilStrategy};
 
 use super::{backend, device, window};
 
@@ -32,17 +32,33 @@ impl<T> EventLoop<T> {
         Ok(EventLoop { elw, user_event_sender, user_event_receiver })
     }
 
-    pub fn run_app<A: ApplicationHandler<T>>(self, app: &mut A) -> ! {
+    pub fn run<F>(self, mut event_handler: F) -> !
+    where
+        F: FnMut(Event<T>, &RootActiveEventLoop),
+    {
         let target = RootActiveEventLoop { p: self.elw.p.clone(), _marker: PhantomData };
 
         // SAFETY: Don't use `move` to make sure we leak the `event_handler` and `target`.
-        let handler: Box<dyn FnMut(Event<()>)> =
-            Box::new(|event| handle_event(app, &target, &self.user_event_receiver, event));
-
+        let handler: Box<dyn FnMut(Event<()>)> = Box::new(|event| {
+            let event = match event.map_nonuser_event() {
+                Ok(event) => event,
+                Err(Event::UserEvent(())) => Event::UserEvent(
+                    self.user_event_receiver
+                        .try_recv()
+                        .expect("handler woken up without user event"),
+                ),
+                Err(_) => unreachable!(),
+            };
+            event_handler(event, &target)
+        });
         // SAFETY: The `transmute` is necessary because `run()` requires `'static`. This is safe
         // because this function will never return and all resources not cleaned up by the point we
         // `throw` will leak, making this actually `'static`.
-        let handler = unsafe { std::mem::transmute(handler) };
+        let handler = unsafe {
+            std::mem::transmute::<Box<dyn FnMut(Event<()>)>, Box<dyn FnMut(Event<()>) + 'static>>(
+                handler,
+            )
+        };
         self.elw.p.run(handler, false);
 
         // Throw an exception to break out of Rust execution and use unreachable to tell the
@@ -54,12 +70,24 @@ impl<T> EventLoop<T> {
         unreachable!();
     }
 
-    pub fn spawn_app<A: ApplicationHandler<T> + 'static>(self, mut app: A) {
+    pub fn spawn<F>(self, mut event_handler: F)
+    where
+        F: 'static + FnMut(Event<T>, &RootActiveEventLoop),
+    {
         let target = RootActiveEventLoop { p: self.elw.p.clone(), _marker: PhantomData };
 
         self.elw.p.run(
             Box::new(move |event| {
-                handle_event(&mut app, &target, &self.user_event_receiver, event)
+                let event = match event.map_nonuser_event() {
+                    Ok(event) => event,
+                    Err(Event::UserEvent(())) => Event::UserEvent(
+                        self.user_event_receiver
+                            .try_recv()
+                            .expect("handler woken up without user event"),
+                    ),
+                    Err(_) => unreachable!(),
+                };
+                event_handler(event, &target)
             }),
             true,
         );
@@ -72,27 +100,20 @@ impl<T> EventLoop<T> {
     pub fn window_target(&self) -> &RootActiveEventLoop {
         &self.elw
     }
-}
 
-fn handle_event<T: 'static, A: ApplicationHandler<T>>(
-    app: &mut A,
-    target: &RootActiveEventLoop,
-    user_event_receiver: &Receiver<T>,
-    event: Event<()>,
-) {
-    match event {
-        Event::NewEvents(cause) => app.new_events(target, cause),
-        Event::WindowEvent { window_id, event } => app.window_event(target, window_id, event),
-        Event::DeviceEvent { device_id, event } => app.device_event(target, device_id, event),
-        Event::UserEvent(_) => {
-            let event =
-                user_event_receiver.try_recv().expect("user event signaled but not received");
-            app.user_event(target, event);
-        },
-        Event::Suspended => app.suspended(target),
-        Event::Resumed => app.resumed(target),
-        Event::AboutToWait => app.about_to_wait(target),
-        Event::LoopExiting => app.exiting(target),
-        Event::MemoryWarning => app.memory_warning(target),
+    pub fn set_poll_strategy(&self, strategy: PollStrategy) {
+        self.elw.set_poll_strategy(strategy);
+    }
+
+    pub fn poll_strategy(&self) -> PollStrategy {
+        self.elw.poll_strategy()
+    }
+
+    pub fn set_wait_until_strategy(&self, strategy: WaitUntilStrategy) {
+        self.elw.set_wait_until_strategy(strategy);
+    }
+
+    pub fn wait_until_strategy(&self) -> WaitUntilStrategy {
+        self.elw.wait_until_strategy()
     }
 }

src/platform_impl/web/event_loop/runner.rs

@@ -1,3 +1,15 @@
+use std::cell::{Cell, RefCell};
+use std::collections::{HashSet, VecDeque};
+use std::iter;
+use std::num::NonZeroUsize;
+use std::ops::Deref;
+use std::rc::{Rc, Weak};
+
+use wasm_bindgen::prelude::Closure;
+use wasm_bindgen::JsCast;
+use web_sys::{Document, KeyboardEvent, PageTransitionEvent, PointerEvent, WheelEvent};
+use web_time::{Duration, Instant};
+
 use super::super::main_thread::MainThreadMarker;
 use super::super::DeviceId;
 use super::backend;
@@ -8,21 +20,12 @@ use crate::event::{
     WindowEvent,
 };
 use crate::event_loop::{ControlFlow, DeviceEvents};
-use crate::platform::web::PollStrategy;
+use crate::platform::web::{PollStrategy, WaitUntilStrategy};
 use crate::platform_impl::platform::backend::EventListenerHandle;
 use crate::platform_impl::platform::r#async::{DispatchRunner, Waker, WakerSpawner};
 use crate::platform_impl::platform::window::Inner;
 use crate::window::WindowId;
 
-use std::cell::{Cell, RefCell};
-use std::collections::{HashSet, VecDeque};
-use std::iter;
-use std::ops::Deref;
-use std::rc::{Rc, Weak};
-use wasm_bindgen::prelude::Closure;
-use web_sys::{Document, KeyboardEvent, PageTransitionEvent, PointerEvent, WheelEvent};
-use web_time::{Duration, Instant};
-
 pub struct Shared(Rc<Execution>);
 
 pub(super) type EventHandler = dyn FnMut(Event<()>);
@@ -40,6 +43,7 @@ pub struct Execution {
     proxy_spawner: WakerSpawner<Weak<Self>>,
     control_flow: Cell<ControlFlow>,
     poll_strategy: Cell<PollStrategy>,
+    wait_until_strategy: Cell<WaitUntilStrategy>,
     exit: Cell<bool>,
     runner: RefCell<RunnerEnum>,
     suspended: Cell<bool>,
@@ -133,18 +137,20 @@ impl Shared {
         let document = window.document().expect("Failed to obtain document");
 
         Shared(Rc::<Execution>::new_cyclic(|weak| {
-            let proxy_spawner = WakerSpawner::new(main_thread, weak.clone(), |runner, count| {
-                if let Some(runner) = runner.upgrade() {
-                    Shared(runner).send_events(iter::repeat(Event::UserEvent(())).take(count))
-                }
-            })
-            .expect("`EventLoop` has to be created in the main thread");
+            let proxy_spawner =
+                WakerSpawner::new(main_thread, weak.clone(), |runner, count, local| {
+                    if let Some(runner) = runner.upgrade() {
+                        Shared(runner).send_user_events(count, local)
+                    }
+                })
+                .expect("`EventLoop` has to be created in the main thread");
 
             Execution {
                 main_thread,
                 proxy_spawner,
                 control_flow: Cell::new(ControlFlow::default()),
                 poll_strategy: Cell::new(PollStrategy::default()),
+                wait_until_strategy: Cell::new(WaitUntilStrategy::default()),
                 exit: Cell::new(false),
                 runner: RefCell::new(RunnerEnum::Pending),
                 suspended: Cell::new(false),
@@ -239,21 +245,10 @@ impl Shared {
                     return;
                 }
 
-                let pointer_type = event.pointer_type();
-
-                if pointer_type != "mouse" {
-                    return;
-                }
-
                 // chorded button event
                 let device_id = RootDeviceId(DeviceId(event.pointer_id()));
 
                 if let Some(button) = backend::event::mouse_button(&event) {
-                    debug_assert_eq!(
-                        pointer_type, "mouse",
-                        "expect pointer type of a chorded button event to be a mouse"
-                    );
-
                     let state = if backend::event::mouse_buttons(&event).contains(button.into()) {
                         ElementState::Pressed
                     } else {
@@ -317,10 +312,6 @@ impl Shared {
                     return;
                 }
 
-                if event.pointer_type() != "mouse" {
-                    return;
-                }
-
                 let button = backend::event::mouse_button(&event).expect("no mouse button pressed");
                 runner.send_event(Event::DeviceEvent {
                     device_id: RootDeviceId(DeviceId(event.pointer_id())),
@@ -340,10 +331,6 @@ impl Shared {
                     return;
                 }
 
-                if event.pointer_type() != "mouse" {
-                    return;
-                }
-
                 let button = backend::event::mouse_button(&event).expect("no mouse button pressed");
                 runner.send_event(Event::DeviceEvent {
                     device_id: RootDeviceId(DeviceId(event.pointer_id())),
@@ -364,7 +351,7 @@ impl Shared {
                 }
 
                 runner.send_event(Event::DeviceEvent {
-                    device_id: RootDeviceId(unsafe { DeviceId::dummy() }),
+                    device_id: RootDeviceId(DeviceId::dummy()),
                     event: DeviceEvent::Key(RawKeyEvent {
                         physical_key: backend::event::key_code(&event),
                         state: ElementState::Pressed,
@@ -382,7 +369,7 @@ impl Shared {
                 }
 
                 runner.send_event(Event::DeviceEvent {
-                    device_id: RootDeviceId(unsafe { DeviceId::dummy() }),
+                    device_id: RootDeviceId(DeviceId::dummy()),
                     event: DeviceEvent::Key(RawKeyEvent {
                         physical_key: backend::event::key_code(&event),
                         state: ElementState::Released,
@@ -460,6 +447,42 @@ impl Shared {
         self.send_events(iter::once(event));
     }
 
+    // Add a series of user events to the event loop runner
+    //
+    // This will schedule the event loop to wake up instead of waking it up immediately if its not
+    // running.
+    pub(crate) fn send_user_events(&self, count: NonZeroUsize, local: bool) {
+        // If the event loop is closed, it should discard any new events
+        if self.is_closed() {
+            return;
+        }
+
+        if local {
+            // If the loop is not running and triggered locally, queue on next microtick.
+            if let Ok(RunnerEnum::Running(_)) =
+                self.0.runner.try_borrow().as_ref().map(Deref::deref)
+            {
+                self.window().queue_microtask(
+                    &Closure::once_into_js({
+                        let this = Rc::downgrade(&self.0);
+                        move || {
+                            if let Some(shared) = this.upgrade() {
+                                Shared(shared).send_events(
+                                    iter::repeat(Event::UserEvent(())).take(count.get()),
+                                )
+                            }
+                        }
+                    })
+                    .unchecked_into(),
+                );
+
+                return;
+            }
+        }
+
+        self.send_events(iter::repeat(Event::UserEvent(())).take(count.get()))
+    }
+
     // Add a series of events to the event loop runner
     //
     // It will determine if the event should be immediately sent to the user or buffered for later
@@ -473,7 +496,7 @@ impl Shared {
         match self.0.runner.try_borrow().as_ref().map(Deref::deref) {
             Ok(RunnerEnum::Running(ref runner)) => {
                 // If we're currently polling, queue this and wait for the poll() method to be
-                // called
+                // called.
                 if let State::Poll { .. } = runner.state {
                     process_immediately = false;
                 }
@@ -647,6 +670,7 @@ impl Shared {
                         start,
                         end,
                         _timeout: backend::Schedule::new_with_duration(
+                            self.wait_until_strategy(),
                             self.window(),
                             move || cloned.resume_time_reached(start, end),
                             delay,
@@ -759,6 +783,14 @@ impl Shared {
         self.0.poll_strategy.get()
     }
 
+    pub(crate) fn set_wait_until_strategy(&self, strategy: WaitUntilStrategy) {
+        self.0.wait_until_strategy.set(strategy)
+    }
+
+    pub(crate) fn wait_until_strategy(&self) -> WaitUntilStrategy {
+        self.0.wait_until_strategy.get()
+    }
+
     pub(crate) fn waker(&self) -> Waker<Weak<Execution>> {
         self.0.proxy_spawner.waker()
     }

src/platform_impl/web/event_loop/window_target.rs

@@ -18,7 +18,7 @@ use crate::event::{
 };
 use crate::event_loop::{ControlFlow, DeviceEvents};
 use crate::keyboard::ModifiersState;
-use crate::platform::web::{CustomCursorFuture, PollStrategy};
+use crate::platform::web::{CustomCursorFuture, PollStrategy, WaitUntilStrategy};
 use crate::platform_impl::platform::cursor::CustomCursor;
 use crate::platform_impl::platform::r#async::Waker;
 use crate::window::{
@@ -142,7 +142,7 @@ impl ActiveEventLoop {
                     }
                 });
 
-                let device_id = RootDeviceId(unsafe { DeviceId::dummy() });
+                let device_id = RootDeviceId(DeviceId::dummy());
 
                 runner.send_events(
                     iter::once(Event::WindowEvent {
@@ -178,7 +178,7 @@ impl ActiveEventLoop {
                     }
                 });
 
-                let device_id = RootDeviceId(unsafe { DeviceId::dummy() });
+                let device_id = RootDeviceId(DeviceId::dummy());
 
                 runner.send_events(
                     iter::once(Event::WindowEvent {
@@ -258,21 +258,6 @@ impl ActiveEventLoop {
         });
 
         canvas.on_cursor_move(
-            {
-                let runner = self.runner.clone();
-                let has_focus = has_focus.clone();
-                let modifiers = self.modifiers.clone();
-
-                move |active_modifiers| {
-                    if has_focus.get() && modifiers.get() != active_modifiers {
-                        modifiers.set(active_modifiers);
-                        runner.send_event(Event::WindowEvent {
-                            window_id: RootWindowId(id),
-                            event: WindowEvent::ModifiersChanged(active_modifiers.into()),
-                        })
-                    }
-                }
-            },
             {
                 let runner = self.runner.clone();
                 let has_focus = has_focus.clone();
@@ -372,20 +357,6 @@ impl ActiveEventLoop {
         );
 
         canvas.on_mouse_press(
-            {
-                let runner = self.runner.clone();
-                let modifiers = self.modifiers.clone();
-
-                move |active_modifiers| {
-                    if modifiers.get() != active_modifiers {
-                        modifiers.set(active_modifiers);
-                        runner.send_event(Event::WindowEvent {
-                            window_id: RootWindowId(id),
-                            event: WindowEvent::ModifiersChanged(active_modifiers.into()),
-                        })
-                    }
-                }
-            },
             {
                 let runner = self.runner.clone();
                 let modifiers = self.modifiers.clone();
@@ -450,21 +421,6 @@ impl ActiveEventLoop {
         );
 
         canvas.on_mouse_release(
-            {
-                let runner = self.runner.clone();
-                let has_focus = has_focus.clone();
-                let modifiers = self.modifiers.clone();
-
-                move |active_modifiers| {
-                    if has_focus.get() && modifiers.get() != active_modifiers {
-                        modifiers.set(active_modifiers);
-                        runner.send_event(Event::WindowEvent {
-                            window_id: RootWindowId(id),
-                            event: WindowEvent::ModifiersChanged(active_modifiers.into()),
-                        });
-                    }
-                }
-            },
             {
                 let runner = self.runner.clone();
                 let has_focus = has_focus.clone();
@@ -605,7 +561,7 @@ impl ActiveEventLoop {
                             window_id: RootWindowId(id),
                             event: WindowEvent::Resized(new_size),
                         });
-                        runner.request_redraw(RootWindowId(id));
+                        canvas.request_animation_frame();
                     }
                 }
             },
@@ -658,6 +614,16 @@ impl ActiveEventLoop {
         self.runner.listen_device_events(allowed)
     }
 
+    pub fn system_theme(&self) -> Option<Theme> {
+        backend::is_dark_mode(self.runner.window()).map(|is_dark_mode| {
+            if is_dark_mode {
+                Theme::Dark
+            } else {
+                Theme::Light
+            }
+        })
+    }
+
     pub(crate) fn set_control_flow(&self, control_flow: ControlFlow) {
         self.runner.set_control_flow(control_flow)
     }
@@ -682,6 +648,14 @@ impl ActiveEventLoop {
         self.runner.poll_strategy()
     }
 
+    pub(crate) fn set_wait_until_strategy(&self, strategy: WaitUntilStrategy) {
+        self.runner.set_wait_until_strategy(strategy)
+    }
+
+    pub(crate) fn wait_until_strategy(&self) -> WaitUntilStrategy {
+        self.runner.wait_until_strategy()
+    }
+
     pub(crate) fn waker(&self) -> Waker<Weak<Execution>> {
         self.runner.waker()
     }

src/platform_impl/web/mod.rs

@@ -28,11 +28,9 @@ mod event_loop;
 mod keyboard;
 mod main_thread;
 mod monitor;
+mod web_sys;
 mod window;
 
-#[path = "web_sys/mod.rs"]
-mod backend;
-
 pub use self::device::DeviceId;
 pub use self::error::OsError;
 pub(crate) use self::event_loop::{
@@ -43,6 +41,7 @@ pub use self::monitor::{MonitorHandle, VideoModeHandle};
 pub use self::window::{PlatformSpecificWindowAttributes, Window, WindowId};
 
 pub(crate) use self::keyboard::KeyEventExtra;
+use self::web_sys as backend;
 pub(crate) use crate::icon::NoIcon as PlatformIcon;
 pub(crate) use crate::platform_impl::Fullscreen;
 pub(crate) use cursor::{

src/platform_impl/web/web_sys/canvas.rs

@@ -329,51 +329,29 @@ impl Canvas {
         self.pointer_handler.on_cursor_enter(&self.common, handler)
     }
 
-    pub fn on_mouse_release<MOD, M, T>(
-        &mut self,
-        modifier_handler: MOD,
-        mouse_handler: M,
-        touch_handler: T,
-    ) where
-        MOD: 'static + FnMut(ModifiersState),
+    pub fn on_mouse_release<M, T>(&mut self, mouse_handler: M, touch_handler: T)
+    where
         M: 'static + FnMut(ModifiersState, i32, PhysicalPosition<f64>, MouseButton),
         T: 'static + FnMut(ModifiersState, i32, PhysicalPosition<f64>, Force),
     {
-        self.pointer_handler.on_mouse_release(
-            &self.common,
-            modifier_handler,
-            mouse_handler,
-            touch_handler,
-        )
+        self.pointer_handler.on_mouse_release(&self.common, mouse_handler, touch_handler)
     }
 
-    pub fn on_mouse_press<MOD, M, T>(
-        &mut self,
-        modifier_handler: MOD,
-        mouse_handler: M,
-        touch_handler: T,
-    ) where
-        MOD: 'static + FnMut(ModifiersState),
+    pub fn on_mouse_press<M, T>(&mut self, mouse_handler: M, touch_handler: T)
+    where
         M: 'static + FnMut(ModifiersState, i32, PhysicalPosition<f64>, MouseButton),
         T: 'static + FnMut(ModifiersState, i32, PhysicalPosition<f64>, Force),
     {
         self.pointer_handler.on_mouse_press(
             &self.common,
-            modifier_handler,
             mouse_handler,
             touch_handler,
             Rc::clone(&self.prevent_default),
         )
     }
 
-    pub fn on_cursor_move<MOD, M, T, B>(
-        &mut self,
-        modifier_handler: MOD,
-        mouse_handler: M,
-        touch_handler: T,
-        button_handler: B,
-    ) where
-        MOD: 'static + FnMut(ModifiersState),
+    pub fn on_cursor_move<M, T, B>(&mut self, mouse_handler: M, touch_handler: T, button_handler: B)
+    where
         M: 'static + FnMut(ModifiersState, i32, &mut dyn Iterator<Item = PhysicalPosition<f64>>),
         T: 'static
             + FnMut(ModifiersState, i32, &mut dyn Iterator<Item = (PhysicalPosition<f64>, Force)>),
@@ -381,7 +359,6 @@ impl Canvas {
     {
         self.pointer_handler.on_cursor_move(
             &self.common,
-            modifier_handler,
             mouse_handler,
             touch_handler,
             button_handler,
@@ -427,8 +404,8 @@ impl Canvas {
 
     pub(crate) fn on_resize_scale<S, R>(&mut self, scale_handler: S, size_handler: R)
     where
-        S: 'static + FnMut(PhysicalSize<u32>, f64),
-        R: 'static + FnMut(PhysicalSize<u32>),
+        S: 'static + Fn(PhysicalSize<u32>, f64),
+        R: 'static + Fn(PhysicalSize<u32>),
     {
         self.on_resize_scale = Some(ResizeScaleHandle::new(
             self.window().clone(),

src/platform_impl/web/web_sys/event.rs

@@ -1,13 +1,15 @@
-use crate::dpi::LogicalPosition;
 use crate::event::{MouseButton, MouseScrollDelta};
 use crate::keyboard::{Key, KeyLocation, ModifiersState, NamedKey, PhysicalKey};
 
+use dpi::{LogicalPosition, PhysicalPosition, Position};
 use smol_str::SmolStr;
 use std::cell::OnceCell;
 use wasm_bindgen::prelude::wasm_bindgen;
 use wasm_bindgen::{JsCast, JsValue};
 use web_sys::{KeyboardEvent, MouseEvent, PointerEvent, WheelEvent};
 
+use super::Engine;
+
 bitflags::bitflags! {
     // https://www.w3.org/TR/pointerevents3/#the-buttons-property
     #[derive(Debug, Clone, Copy, PartialEq, Eq)]
@@ -95,42 +97,48 @@ pub fn mouse_position(event: &MouseEvent) -> LogicalPosition<f64> {
     LogicalPosition { x: event.offset_x(), y: event.offset_y() }
 }
 
-// TODO: Remove this when Firefox supports correct movement values in coalesced events.
+// TODO: Remove this when Firefox supports correct movement values in coalesced events and browsers
+// have agreed on what coordinate space `movementX/Y` is using.
 // See <https://bugzilla.mozilla.org/show_bug.cgi?id=1753724>.
-pub struct MouseDelta(Option<MouseDeltaInner>);
-
-pub struct MouseDeltaInner {
-    old_position: LogicalPosition<f64>,
-    old_delta: LogicalPosition<f64>,
+// See <https://github.com/w3c/pointerlock/issues/42>.
+pub enum MouseDelta {
+    Chromium,
+    Gecko { old_position: LogicalPosition<f64>, old_delta: LogicalPosition<f64> },
+    Other,
 }
 
 impl MouseDelta {
     pub fn init(window: &web_sys::Window, event: &PointerEvent) -> Self {
-        // Firefox has wrong movement values in coalesced events, we will detect that by checking
-        // for `pointerrawupdate` support. Presumably an implementation of `pointerrawupdate`
-        // should require correct movement values, otherwise uncoalesced events might be broken as
-        // well.
-        Self((!has_pointer_raw_support(window) && has_coalesced_events_support(event)).then(|| {
-            MouseDeltaInner {
+        match super::engine(window) {
+            Some(Engine::Chromium) => Self::Chromium,
+            // Firefox has wrong movement values in coalesced events.
+            Some(Engine::Gecko) if has_coalesced_events_support(event) => Self::Gecko {
                 old_position: mouse_position(event),
-                old_delta: LogicalPosition {
-                    x: event.movement_x() as f64,
-                    y: event.movement_y() as f64,
-                },
-            }
-        }))
+                old_delta: LogicalPosition::new(
+                    event.movement_x() as f64,
+                    event.movement_y() as f64,
+                ),
+            },
+            _ => Self::Other,
+        }
     }
 
-    pub fn delta(&mut self, event: &MouseEvent) -> LogicalPosition<f64> {
-        if let Some(inner) = &mut self.0 {
-            let new_position = mouse_position(event);
-            let x = new_position.x - inner.old_position.x + inner.old_delta.x;
-            let y = new_position.y - inner.old_position.y + inner.old_delta.y;
-            inner.old_position = new_position;
-            inner.old_delta = LogicalPosition::new(0., 0.);
-            LogicalPosition::new(x, y)
-        } else {
-            LogicalPosition { x: event.movement_x() as f64, y: event.movement_y() as f64 }
+    pub fn delta(&mut self, event: &MouseEvent) -> Position {
+        match self {
+            MouseDelta::Chromium => {
+                PhysicalPosition::new(event.movement_x(), event.movement_y()).into()
+            },
+            MouseDelta::Gecko { old_position, old_delta } => {
+                let new_position = mouse_position(event);
+                let x = new_position.x - old_position.x + old_delta.x;
+                let y = new_position.y - old_position.y + old_delta.y;
+                *old_position = new_position;
+                *old_delta = LogicalPosition::new(0., 0.);
+                LogicalPosition::new(x, y).into()
+            },
+            MouseDelta::Other => {
+                LogicalPosition::new(event.movement_x(), event.movement_y()).into()
+            },
         }
     }
 }
@@ -238,29 +246,6 @@ pub fn pointer_move_event(event: PointerEvent) -> impl Iterator<Item = PointerEv
     }
 }
 
-// TODO: Remove when all browsers implement it correctly.
-// See <https://github.com/rust-windowing/winit/issues/2875>.
-pub fn has_pointer_raw_support(window: &web_sys::Window) -> bool {
-    thread_local! {
-        static POINTER_RAW_SUPPORT: OnceCell<bool> = const { OnceCell::new() };
-    }
-
-    POINTER_RAW_SUPPORT.with(|support| {
-        *support.get_or_init(|| {
-            #[wasm_bindgen]
-            extern "C" {
-                type PointerRawSupport;
-
-                #[wasm_bindgen(method, getter, js_name = onpointerrawupdate)]
-                fn has_on_pointerrawupdate(this: &PointerRawSupport) -> JsValue;
-            }
-
-            let support: &PointerRawSupport = window.unchecked_ref();
-            !support.has_on_pointerrawupdate().is_undefined()
-        })
-    })
-}
-
 // TODO: Remove when Safari supports `getCoalescedEvents`.
 // See <https://bugs.webkit.org/show_bug.cgi?id=210454>.
 pub fn has_coalesced_events_support(event: &PointerEvent) -> bool {

src/platform_impl/web/web_sys/mod.rs

@@ -9,6 +9,8 @@ mod pointer;
 mod resize_scaling;
 mod schedule;
 
+use std::sync::OnceLock;
+
 pub use self::canvas::{Canvas, Style};
 pub use self::event::ButtonsState;
 pub use self::event_handle::EventListenerHandle;
@@ -16,8 +18,13 @@ pub use self::resize_scaling::ResizeScaleHandle;
 pub use self::schedule::Schedule;
 
 use crate::dpi::{LogicalPosition, LogicalSize};
+use js_sys::Array;
 use wasm_bindgen::closure::Closure;
-use web_sys::{Document, HtmlCanvasElement, PageTransitionEvent, VisibilityState};
+use wasm_bindgen::prelude::wasm_bindgen;
+use wasm_bindgen::JsCast;
+use web_sys::{
+    Document, HtmlCanvasElement, Navigator, PageTransitionEvent, VisibilityState, Window,
+};
 
 pub fn throw(msg: &str) {
     wasm_bindgen::throw_str(msg);
@@ -158,3 +165,69 @@ pub fn is_visible(document: &Document) -> bool {
 }
 
 pub type RawCanvasType = HtmlCanvasElement;
+
+#[derive(Clone, Copy)]
+pub enum Engine {
+    Chromium,
+    Gecko,
+    WebKit,
+}
+
+pub fn engine(window: &Window) -> Option<Engine> {
+    static ENGINE: OnceLock<Option<Engine>> = OnceLock::new();
+
+    #[wasm_bindgen]
+    extern "C" {
+        #[wasm_bindgen(extends = Navigator)]
+        type NavigatorExt;
+
+        #[wasm_bindgen(method, getter, js_name = userAgentData)]
+        fn user_agent_data(this: &NavigatorExt) -> Option<NavigatorUaData>;
+
+        type NavigatorUaData;
+
+        #[wasm_bindgen(method, getter)]
+        fn brands(this: &NavigatorUaData) -> Array;
+
+        type NavigatorUaBrandVersion;
+
+        #[wasm_bindgen(method, getter)]
+        fn brand(this: &NavigatorUaBrandVersion) -> String;
+    }
+
+    *ENGINE.get_or_init(|| {
+        let navigator: NavigatorExt = window.navigator().unchecked_into();
+
+        if let Some(data) = navigator.user_agent_data() {
+            for brand in data
+                .brands()
+                .iter()
+                .map(NavigatorUaBrandVersion::unchecked_from_js)
+                .map(|brand| brand.brand())
+            {
+                match brand.as_str() {
+                    "Chromium" => return Some(Engine::Chromium),
+                    // TODO: verify when Firefox actually implements it.
+                    "Gecko" => return Some(Engine::Gecko),
+                    // TODO: verify when Safari actually implements it.
+                    "WebKit" => return Some(Engine::WebKit),
+                    _ => (),
+                }
+            }
+
+            None
+        } else {
+            let data = navigator.user_agent().ok()?;
+
+            if data.contains("Chrome/") {
+                Some(Engine::Chromium)
+            } else if data.contains("Gecko/") {
+                Some(Engine::Gecko)
+            } else if data.contains("AppleWebKit/") {
+                Some(Engine::WebKit)
+            } else {
+                None
+            }
+        }
+    })
+}

src/platform_impl/web/web_sys/pointer.rs

@@ -44,7 +44,7 @@ impl PointerHandler {
                 // touch events are handled separately
                 // handling them here would produce duplicate mouse events, inconsistent with
                 // other platforms.
-                let pointer_id = (event.pointer_type() == "mouse").then(|| event.pointer_id());
+                let pointer_id = (event.pointer_type() != "touch").then(|| event.pointer_id());
 
                 handler(modifiers, pointer_id);
             }));
@@ -61,20 +61,18 @@ impl PointerHandler {
                 // touch events are handled separately
                 // handling them here would produce duplicate mouse events, inconsistent with
                 // other platforms.
-                let pointer_id = (event.pointer_type() == "mouse").then(|| event.pointer_id());
+                let pointer_id = (event.pointer_type() != "touch").then(|| event.pointer_id());
 
                 handler(modifiers, pointer_id);
             }));
     }
 
-    pub fn on_mouse_release<MOD, M, T>(
+    pub fn on_mouse_release<M, T>(
         &mut self,
         canvas_common: &Common,
-        mut modifier_handler: MOD,
         mut mouse_handler: M,
         mut touch_handler: T,
     ) where
-        MOD: 'static + FnMut(ModifiersState),
         M: 'static + FnMut(ModifiersState, i32, PhysicalPosition<f64>, MouseButton),
         T: 'static + FnMut(ModifiersState, i32, PhysicalPosition<f64>, Force),
     {
@@ -90,26 +88,23 @@ impl PointerHandler {
                         event::mouse_position(&event).to_physical(super::scale_factor(&window)),
                         Force::Normalized(event.pressure() as f64),
                     ),
-                    "mouse" => mouse_handler(
+                    _ => mouse_handler(
                         modifiers,
                         event.pointer_id(),
                         event::mouse_position(&event).to_physical(super::scale_factor(&window)),
                         event::mouse_button(&event).expect("no mouse button released"),
                     ),
-                    _ => modifier_handler(modifiers),
                 }
             }));
     }
 
-    pub fn on_mouse_press<MOD, M, T>(
+    pub fn on_mouse_press<M, T>(
         &mut self,
         canvas_common: &Common,
-        mut modifier_handler: MOD,
         mut mouse_handler: M,
         mut touch_handler: T,
         prevent_default: Rc<Cell<bool>>,
     ) where
-        MOD: 'static + FnMut(ModifiersState),
         M: 'static + FnMut(ModifiersState, i32, PhysicalPosition<f64>, MouseButton),
         T: 'static + FnMut(ModifiersState, i32, PhysicalPosition<f64>, Force),
     {
@@ -125,8 +120,9 @@ impl PointerHandler {
                 }
 
                 let modifiers = event::mouse_modifiers(&event);
+                let pointer_type = &event.pointer_type();
 
-                match event.pointer_type().as_str() {
+                match pointer_type.as_str() {
                     "touch" => {
                         touch_handler(
                             modifiers,
@@ -135,7 +131,7 @@ impl PointerHandler {
                             Force::Normalized(event.pressure() as f64),
                         );
                     },
-                    "mouse" => {
+                    _ => {
                         mouse_handler(
                             modifiers,
                             event.pointer_id(),
@@ -143,27 +139,27 @@ impl PointerHandler {
                             event::mouse_button(&event).expect("no mouse button pressed"),
                         );
 
-                        // Error is swallowed here since the error would occur every time the mouse
-                        // is clicked when the cursor is grabbed, and there
-                        // is probably not a situation where this could
-                        // fail, that we care if it fails.
-                        let _e = canvas.set_pointer_capture(event.pointer_id());
+                        if pointer_type == "mouse" {
+                            // Error is swallowed here since the error would occur every time the
+                            // mouse is clicked when the cursor is
+                            // grabbed, and there is probably not a
+                            // situation where this could fail, that we
+                            // care if it fails.
+                            let _e = canvas.set_pointer_capture(event.pointer_id());
+                        }
                     },
-                    _ => modifier_handler(modifiers),
                 }
             }));
     }
 
-    pub fn on_cursor_move<MOD, M, T, B>(
+    pub fn on_cursor_move<M, T, B>(
         &mut self,
         canvas_common: &Common,
-        mut modifier_handler: MOD,
         mut mouse_handler: M,
         mut touch_handler: T,
         mut button_handler: B,
         prevent_default: Rc<Cell<bool>>,
     ) where
-        MOD: 'static + FnMut(ModifiersState),
         M: 'static + FnMut(ModifiersState, i32, &mut dyn Iterator<Item = PhysicalPosition<f64>>),
         T: 'static
             + FnMut(ModifiersState, i32, &mut dyn Iterator<Item = (PhysicalPosition<f64>, Force)>),
@@ -175,23 +171,10 @@ impl PointerHandler {
             Some(canvas_common.add_event("pointermove", move |event: PointerEvent| {
                 let modifiers = event::mouse_modifiers(&event);
 
-                let pointer_type = event.pointer_type();
-
-                if let "touch" | "mouse" = pointer_type.as_str() {
-                } else {
-                    modifier_handler(modifiers);
-                    return;
-                }
-
                 let id = event.pointer_id();
 
                 // chorded button event
                 if let Some(button) = event::mouse_button(&event) {
-                    debug_assert_eq!(
-                        pointer_type, "mouse",
-                        "expect pointer type of a chorded button event to be a mouse"
-                    );
-
                     if prevent_default.get() {
                         // prevent text selection
                         event.prevent_default();
@@ -212,13 +195,7 @@ impl PointerHandler {
 
                 // pointer move event
                 let scale = super::scale_factor(&window);
-                match pointer_type.as_str() {
-                    "mouse" => mouse_handler(
-                        modifiers,
-                        id,
-                        &mut event::pointer_move_event(event)
-                            .map(|event| event::mouse_position(&event).to_physical(scale)),
-                    ),
+                match event.pointer_type().as_str() {
                     "touch" => touch_handler(
                         modifiers,
                         id,
@@ -229,7 +206,12 @@ impl PointerHandler {
                             )
                         }),
                     ),
-                    _ => unreachable!("didn't return early before"),
+                    _ => mouse_handler(
+                        modifiers,
+                        id,
+                        &mut event::pointer_move_event(event)
+                            .map(|event| event::mouse_position(&event).to_physical(scale)),
+                    ),
                 };
             }));
     }

src/platform_impl/web/web_sys/resize_scaling.rs

@@ -16,7 +16,7 @@ use super::media_query_handle::MediaQueryListHandle;
 use std::cell::{Cell, RefCell};
 use std::rc::Rc;
 
-pub struct ResizeScaleHandle(Rc<RefCell<ResizeScaleInternal>>);
+pub struct ResizeScaleHandle(Rc<ResizeScaleInternal>);
 
 impl ResizeScaleHandle {
     pub(crate) fn new<S, R>(
@@ -28,8 +28,8 @@ impl ResizeScaleHandle {
         resize_handler: R,
     ) -> Self
     where
-        S: 'static + FnMut(PhysicalSize<u32>, f64),
-        R: 'static + FnMut(PhysicalSize<u32>),
+        S: 'static + Fn(PhysicalSize<u32>, f64),
+        R: 'static + Fn(PhysicalSize<u32>),
     {
         Self(ResizeScaleInternal::new(
             window,
@@ -42,7 +42,7 @@ impl ResizeScaleHandle {
     }
 
     pub(crate) fn notify_resize(&self) {
-        self.0.borrow_mut().notify()
+        self.0.notify()
     }
 }
 
@@ -53,11 +53,11 @@ struct ResizeScaleInternal {
     document: Document,
     canvas: HtmlCanvasElement,
     style: Style,
-    mql: MediaQueryListHandle,
+    mql: RefCell<MediaQueryListHandle>,
     observer: ResizeObserver,
     _observer_closure: Closure<dyn FnMut(Array, ResizeObserver)>,
-    scale_handler: Box<dyn FnMut(PhysicalSize<u32>, f64)>,
-    resize_handler: Box<dyn FnMut(PhysicalSize<u32>)>,
+    scale_handler: Box<dyn Fn(PhysicalSize<u32>, f64)>,
+    resize_handler: Box<dyn Fn(PhysicalSize<u32>)>,
     notify_scale: Cell<bool>,
 }
 
@@ -69,12 +69,12 @@ impl ResizeScaleInternal {
         style: Style,
         scale_handler: S,
         resize_handler: R,
-    ) -> Rc<RefCell<Self>>
+    ) -> Rc<Self>
     where
-        S: 'static + FnMut(PhysicalSize<u32>, f64),
-        R: 'static + FnMut(PhysicalSize<u32>),
+        S: 'static + Fn(PhysicalSize<u32>, f64),
+        R: 'static + Fn(PhysicalSize<u32>),
     {
-        Rc::<RefCell<ResizeScaleInternal>>::new_cyclic(|weak_self| {
+        Rc::<ResizeScaleInternal>::new_cyclic(|weak_self| {
             let mql = Self::create_mql(&window, {
                 let weak_self = weak_self.clone();
                 move |mql| {
@@ -86,9 +86,7 @@ impl ResizeScaleInternal {
 
             let weak_self = weak_self.clone();
             let observer_closure = Closure::new(move |entries: Array, _| {
-                if let Some(rc_self) = weak_self.upgrade() {
-                    let mut this = rc_self.borrow_mut();
-
+                if let Some(this) = weak_self.upgrade() {
                     let size = this.process_entry(entries);
 
                     if this.notify_scale.replace(false) {
@@ -101,18 +99,18 @@ impl ResizeScaleInternal {
             });
             let observer = Self::create_observer(&canvas, observer_closure.as_ref());
 
-            RefCell::new(Self {
+            Self {
                 window,
                 document,
                 canvas,
                 style,
-                mql,
+                mql: RefCell::new(mql),
                 observer,
                 _observer_closure: observer_closure,
                 scale_handler: Box::new(scale_handler),
                 resize_handler: Box::new(resize_handler),
                 notify_scale: Cell::new(false),
-            })
+            }
         })
     }
 
@@ -141,10 +139,9 @@ impl ResizeScaleInternal {
 
         // Safari doesn't support `devicePixelContentBoxSize`
         if has_device_pixel_support() {
-            observer.observe_with_options(
-                canvas,
-                ResizeObserverOptions::new().box_(ResizeObserverBoxOptions::DevicePixelContentBox),
-            );
+            let options = ResizeObserverOptions::new();
+            options.set_box(ResizeObserverBoxOptions::DevicePixelContentBox);
+            observer.observe_with_options(canvas, &options);
         } else {
             observer.observe(canvas);
         }
@@ -152,7 +149,7 @@ impl ResizeScaleInternal {
         observer
     }
 
-    fn notify(&mut self) {
+    fn notify(&self) {
         if !self.document.contains(Some(&self.canvas)) || self.style.get("display") == "none" {
             let size = PhysicalSize::new(0, 0);
 
@@ -200,10 +197,9 @@ impl ResizeScaleInternal {
         }
     }
 
-    fn handle_scale(this: Rc<RefCell<Self>>, mql: &MediaQueryList) {
-        let weak_self = Rc::downgrade(&this);
-        let mut this = this.borrow_mut();
-        let scale = super::scale_factor(&this.window);
+    fn handle_scale(self: Rc<Self>, mql: &MediaQueryList) {
+        let weak_self = Rc::downgrade(&self);
+        let scale = super::scale_factor(&self.window);
 
         // TODO: confirm/reproduce this problem, see:
         // <https://github.com/rust-windowing/winit/issues/2597>.
@@ -217,15 +213,15 @@ impl ResizeScaleInternal {
             return;
         }
 
-        let new_mql = Self::create_mql(&this.window, move |mql| {
+        let new_mql = Self::create_mql(&self.window, move |mql| {
             if let Some(rc_self) = weak_self.upgrade() {
                 Self::handle_scale(rc_self, mql);
             }
         });
-        this.mql = new_mql;
+        self.mql.replace(new_mql);
 
-        this.notify_scale.set(true);
-        this.notify();
+        self.notify_scale.set(true);
+        self.notify();
     }
 
     fn process_entry(&self, entries: Array) -> PhysicalSize<u32> {

src/platform_impl/web/web_sys/schedule.rs

@@ -1,12 +1,14 @@
-use js_sys::{Function, Object, Promise, Reflect};
+use js_sys::{Array, Function, Object, Promise, Reflect};
 use std::cell::OnceCell;
 use std::time::Duration;
 use wasm_bindgen::closure::Closure;
 use wasm_bindgen::prelude::wasm_bindgen;
 use wasm_bindgen::{JsCast, JsValue};
-use web_sys::{AbortController, AbortSignal, MessageChannel, MessagePort};
+use web_sys::{
+    AbortController, AbortSignal, Blob, BlobPropertyBag, MessageChannel, MessagePort, Url, Worker,
+};
 
-use crate::platform::web::PollStrategy;
+use crate::platform::web::{PollStrategy, WaitUntilStrategy};
 
 #[derive(Debug)]
 pub struct Schedule {
@@ -29,6 +31,7 @@ enum Inner {
         port: MessagePort,
         _timeout_closure: Closure<dyn FnMut()>,
     },
+    Worker(MessagePort),
 }
 
 impl Schedule {
@@ -45,14 +48,24 @@ impl Schedule {
         }
     }
 
-    pub fn new_with_duration<F>(window: &web_sys::Window, f: F, duration: Duration) -> Schedule
+    pub fn new_with_duration<F>(
+        strategy: WaitUntilStrategy,
+        window: &web_sys::Window,
+        f: F,
+        duration: Duration,
+    ) -> Schedule
     where
         F: 'static + FnMut(),
     {
-        if has_scheduler_support(window) {
-            Self::new_scheduler(window, f, Some(duration))
-        } else {
-            Self::new_timeout(window.clone(), f, Some(duration))
+        match strategy {
+            WaitUntilStrategy::Scheduler => {
+                if has_scheduler_support(window) {
+                    Self::new_scheduler(window, f, Some(duration))
+                } else {
+                    Self::new_timeout(window.clone(), f, Some(duration))
+                }
+            },
+            WaitUntilStrategy::Worker => Self::new_worker(f, duration),
         }
     }
 
@@ -153,6 +166,44 @@ impl Schedule {
             },
         }
     }
+
+    fn new_worker<F>(f: F, duration: Duration) -> Schedule
+    where
+        F: 'static + FnMut(),
+    {
+        thread_local! {
+            static URL: ScriptUrl = ScriptUrl::new(include_str!("worker.min.js"));
+            static WORKER: Worker = URL.with(|url| Worker::new(&url.0)).expect("`new Worker()` is not expected to fail with a local script");
+        }
+
+        let channel = MessageChannel::new().unwrap();
+        let closure = Closure::new(f);
+        let port_1 = channel.port1();
+        port_1.set_onmessage(Some(closure.as_ref().unchecked_ref()));
+        port_1.start();
+
+        // `Duration::as_millis()` always rounds down (because of truncation), we want to round
+        // up instead. This makes sure that the we never wake up **before** the given time.
+        let duration = duration
+            .as_secs()
+            .try_into()
+            .ok()
+            .and_then(|secs: u32| secs.checked_mul(1000))
+            .and_then(|secs| secs.checked_add(duration_millis_ceil(duration)))
+            .unwrap_or(u32::MAX);
+
+        WORKER
+            .with(|worker| {
+                let port_2 = channel.port2();
+                worker.post_message_with_transfer(
+                    &Array::of2(&port_2, &duration.into()),
+                    &Array::of1(&port_2).into(),
+                )
+            })
+            .expect("`Worker.postMessage()` is not expected to fail");
+
+        Schedule { _closure: closure, inner: Inner::Worker(port_1) }
+    }
 }
 
 impl Drop for Schedule {
@@ -165,6 +216,10 @@ impl Drop for Schedule {
                 port.close();
                 port.set_onmessage(None);
             },
+            Inner::Worker(port) => {
+                port.close();
+                port.set_onmessage(None);
+            },
         }
     }
 }
@@ -226,6 +281,29 @@ fn has_idle_callback_support(window: &web_sys::Window) -> bool {
     })
 }
 
+struct ScriptUrl(String);
+
+impl ScriptUrl {
+    fn new(script: &str) -> Self {
+        let sequence = Array::of1(&script.into());
+        let property = BlobPropertyBag::new();
+        property.set_type("text/javascript");
+        let blob = Blob::new_with_str_sequence_and_options(&sequence, &property)
+            .expect("`new Blob()` should never throw");
+
+        let url = Url::create_object_url_with_blob(&blob)
+            .expect("`URL.createObjectURL()` should never throw");
+
+        Self(url)
+    }
+}
+
+impl Drop for ScriptUrl {
+    fn drop(&mut self) {
+        Url::revoke_object_url(&self.0).expect("`URL.revokeObjectURL()` should never throw");
+    }
+}
+
 #[wasm_bindgen]
 extern "C" {
     type WindowSupportExt;

src/platform_impl/web/web_sys/worker.js

@@ -0,0 +1,10 @@
+onmessage = event => {
+    const [port, timeout] = event.data
+    const f = () => port.postMessage(undefined)
+
+    if ('scheduler' in this) {
+        scheduler.postTask(f, { delay: timeout })
+    } else {
+        setTimeout(f, timeout)
+    }
+}

src/platform_impl/web/web_sys/worker.min.js

@@ -0,0 +1 @@
+onmessage=e=>{let[s,t]=e.data,a=()=>s.postMessage(void 0);"scheduler"in this?scheduler.postTask(a,{delay:t}):setTimeout(a,t)};

src/platform_impl/web/window.rs

@@ -431,7 +431,7 @@ impl Drop for Inner {
 pub struct WindowId(pub(crate) u32);
 
 impl WindowId {
-    pub const unsafe fn dummy() -> Self {
+    pub const fn dummy() -> Self {
         Self(0)
     }
 }

src/platform_impl/windows/dark_mode.rs

@@ -123,7 +123,7 @@ fn set_dark_mode_for_window(hwnd: HWND, is_dark_mode: bool) -> bool {
     }
 }
 
-fn should_use_dark_mode() -> bool {
+pub fn should_use_dark_mode() -> bool {
     should_apps_use_dark_mode() && !is_high_contrast()
 }
 
@@ -132,7 +132,13 @@ fn should_apps_use_dark_mode() -> bool {
     static SHOULD_APPS_USE_DARK_MODE: Lazy<Option<ShouldAppsUseDarkMode>> = Lazy::new(|| unsafe {
         const UXTHEME_SHOULDAPPSUSEDARKMODE_ORDINAL: PCSTR = 132 as PCSTR;
 
-        let module = LoadLibraryA("uxtheme.dll\0".as_ptr());
+        // We won't try to do anything for windows versions < 17763
+        // (Windows 10 October 2018 update)
+        if !*DARK_MODE_SUPPORTED {
+            return None;
+        }
+
+        let module = LoadLibraryA("uxtheme.dll\0".as_ptr().cast());
 
         if module == 0 {
             return None;