Remove dark-light dependency (#2929)

* Remove dark-light dependency

Since https://github.com/emilk/egui/pull/2750 we now get what we need
straight from `winit`.

* fix warning

* Docstring formatting

* fix typo in check.sh

crates/eframe/Cargo.toml

@@ -26,11 +26,6 @@ default = ["accesskit", "default_fonts", "glow"]
 ## Enable platform accessibility API implementations through [AccessKit](https://accesskit.dev/).
 accesskit = ["egui/accesskit", "egui-winit/accesskit"]
 
-## Detect dark mode system preference using [`dark-light`](https://docs.rs/dark-light).
-##
-## See also [`NativeOptions::follow_system_theme`] and [`NativeOptions::default_theme`].
-dark-light = ["dep:dark-light"]
-
 ## If set, egui will use `include_bytes!` to bundle some fonts.
 ## If you plan on specifying your own fonts you may disable this feature.
 default_fonts = ["egui/default_fonts"]
@@ -107,7 +102,6 @@ raw-window-handle = { version = "0.5.0" }
 winit = "0.28.1"
 
 # optional native:
-dark-light = { version = "1.0", optional = true }
 directories-next = { version = "2", optional = true }
 egui-wgpu = { version = "0.21.0", path = "../egui-wgpu", optional = true, features = [
   "winit",

crates/eframe/src/epi.rs

@@ -328,18 +328,15 @@ pub struct NativeOptions {
 
     /// Try to detect and follow the system preferred setting for dark vs light mode.
     ///
-    /// By default, this is `true` on Mac and Windows, but `false` on Linux
-    /// due to <https://github.com/frewsxcv/rust-dark-light/issues/17>.
+    /// The theme will automatically change when the dark vs light mode preference is changed.
     ///
-    /// On Mac and Windows the theme will automatically change when the dark vs light mode preference is changed.
-    ///
-    /// This only works on Linux if the `dark-light` feature is enabled.
+    /// Does not work on Linux (see <https://github.com/rust-windowing/winit/issues/1549>).
     ///
     /// See also [`Self::default_theme`].
     pub follow_system_theme: bool,
 
     /// Which theme to use in case [`Self::follow_system_theme`] is `false`
-    /// or the `dark-light` feature is disabled.
+    /// or eframe fails to detect the system theme.
     ///
     /// Default: [`Theme::Dark`].
     pub default_theme: Theme,
@@ -454,30 +451,6 @@ impl Default for NativeOptions {
     }
 }
 
-#[cfg(not(target_arch = "wasm32"))]
-impl NativeOptions {
-    /// The theme used by the system.
-    #[cfg(feature = "dark-light")]
-    pub fn system_theme(&self) -> Option<Theme> {
-        if self.follow_system_theme {
-            crate::profile_scope!("dark_light::detect");
-            match dark_light::detect() {
-                dark_light::Mode::Dark => Some(Theme::Dark),
-                dark_light::Mode::Light => Some(Theme::Light),
-                dark_light::Mode::Default => None,
-            }
-        } else {
-            None
-        }
-    }
-
-    /// The theme used by the system.
-    #[cfg(not(feature = "dark-light"))]
-    pub fn system_theme(&self) -> Option<Theme> {
-        None
-    }
-}
-
 // ----------------------------------------------------------------------------
 
 /// Options when using `eframe` in a web page.

crates/eframe/src/native/run.rs

@@ -1450,9 +1450,8 @@ fn system_theme(window: &winit::window::Window, options: &NativeOptions) -> Opti
 }
 
 // Winit only reads the system theme on macOS and Windows.
-// On Linux we have to fall back on dark-light (if enabled).
 // See: https://github.com/rust-windowing/winit/issues/1549
 #[cfg(not(any(target_os = "windows", target_os = "macos")))]
-fn system_theme(_window: &winit::window::Window, options: &NativeOptions) -> Option<crate::Theme> {
-    options.system_theme()
+fn system_theme(_window: &winit::window::Window, _options: &NativeOptions) -> Option<crate::Theme> {
+    None
 }