This changes the monitor selection used when restoring a persisted
window position.
Currently, `egui-winit` picks a monitor by checking whether the saved
window position fits inside a loose monitor range. This can choose the
wrong monitor when a saved window rectangle slightly overlaps another
monitor.
My failure case was on Windows with two monitors:
- primary monitor on the right
- secondary monitor on the left
- window maximized on the primary monitor
- persisted outer position was slightly negative, e.g. `x = -8`, because
of the invisible window border
That position matched both monitor ranges, so the restored maximized
window could
open on the secondary monitor instead of the primary one.
This PR picks the monitor with the largest overlap with the saved window
rectangle instead.
Related note: probably the best solution would be to save the normal
window position when maximized, so that when unmaximizing, the window
would get restored to the previous state. It's mentioned in this comment
https://github.com/emilk/egui/issues/3494#issuecomment-1986985211. I
tried doing that in
[fix-windows-maximized-restore-placement](https://github.com/YelovSK/egui/tree/fix-windows-maximized-restore-placement),
and it works, but it requires adding windows-sys as a dependency to call
a relevant winapi, so that's probably not the right solution. Winit
doesn't seem to provide an API that would return this information.
* [x] I have followed the instructions in the PR template
---------
Co-authored-by: Emil Ernerfeldt <emil.ernerfeldt@gmail.com>
Current behavior fails when translating file uris that contain windows
UNC paths. This commit attempts to fix that behavior by looking at the
hostname attribute of the uri and changing behavior if the hostname is
present.
* Closes <https://github.com/emilk/egui/issues/8161>
* [x] I have followed the instructions in the PR template
The three methods for showing a `Panel` are now:
* `panel.show`: always show the panel.
* `panel.show_collapsible`: show or hide the panel, with a slide
animation in between.
* `Panel::show_switched`: animate between two different panels: a
thin/collapsed one and a thick/expanded one.
* Closes https://github.com/emilk/egui/pull/7254
You can now drag-to-close a panel. Also drag-to-expand panels.
This is a breaking change: the animated panel functions now take a
`open: &mut bool` instead of `open: bool`.
This is only enabled for resizable panels
## What
Adds a way for apps to push an RGBA bitmap as the OS cursor — the
missing companion to `Context::set_cursor_icon`. The integration
translates it into a real `winit::CustomCursor`, so the cursor is drawn
by the compositor and can extend past the egui window edge like any
native cursor.
## Why
Apps with custom-shaped windows (Winamp-style skins, themed launchers,
kiosk apps) currently have no clean way to display a custom cursor:
- `CursorIcon` is limited to the standard system enum.
- Painting the cursor sprite via `egui::Painter` works inside the canvas
but gets clipped at the window edge — the bottom/right of the cursor
disappears the moment the pointer is near the boundary, and there's no
way to render onto the desktop area exposed by a
transparent/region-shaped window.
`winit` 0.30+ already supports `CustomCursor::from_rgba` +
`ActiveEventLoop::create_custom_cursor`, but `egui-winit` doesn't
surface it. This PR exposes it through egui.
### Visual demonstration
Driving use case: a Winamp WSZ skin player
([all3f0r1/oneamp](https://github.com/all3f0r1/oneamp)) with a
transparent + region-shaped window where the skin ships its own `.cur`
files. The bottom-right corner of the playlist exposes the resize cursor
— notice how it gets clipped at the window edge in the painter-based
approach.
| Before (cursor painted via `egui::Painter`) | After (cursor pushed via
`set_cursor_image`) |
| --- | --- |
| 
| 
|
## API
```rust
// new in egui::data::output
pub struct CustomCursorImage {
pub rgba: std::sync::Arc<[u8]>,
pub size: [u16; 2], // matches winit's u16 to avoid lossy casts
pub hotspot: [u16; 2],
}
// new field on PlatformOutput (skipped from serde — ephemeral)
pub cursor_image: Option<CustomCursorImage>,
// new method on Context
ctx.set_cursor_image(Some(image)); // overrides cursor_icon for this frame
ctx.set_cursor_image(None); // revert to cursor_icon
```
`Arc<[u8]>` is intentional: the integration dedupes by `Arc::as_ptr`, so
reusing the same Arc across frames means the bitmap is only uploaded to
the OS once per skin, not once per frame.
## Integration changes
- `egui_winit::State::handle_platform_output_with_event_loop(window,
Option<&ActiveEventLoop>, ...)` is a new method that threads the active
event loop so it can call `event_loop.create_custom_cursor(...)`.
- The legacy `handle_platform_output(window, ...)` delegates with `None`
and silently drops `cursor_image`. **No existing callers break.**
- The icon and bitmap paths are unified in a private `apply_cursor`. The
no-flicker dedupe of the old `set_cursor_icon` is preserved on both
paths.
- If `CustomCursor::from_rgba` rejects the bitmap (bad dimensions,
hotspot OOB, etc.), we log a warning and fall back to the icon path.
- eframe's wgpu + glow integrations thread `&ActiveEventLoop` through
`run_ui_and_paint` (glow already had it; wgpu needed one extra
parameter) and call the new method.
- Immediate viewports keep the old path because they're invoked from a
`Context` callback that doesn't have an event loop reference. Custom
cursors are a no-op in immediate viewports — acceptable since they're a
niche path.
## Fallback semantics
| backend / context | what happens |
|--------------------------------|-------------------------------|
| eframe wgpu/glow main viewport | bitmap displayed via OS |
| eframe immediate viewport | falls back to `cursor_icon` |
| eframe web | falls back to `cursor_icon` |
| custom integrations not opted in | falls back to `cursor_icon` |
| `from_rgba` returns `BadImage` | warning + falls back to icon |
## Verification
- `cargo fmt --all -- --check` ✅
- `cargo clippy -p egui -p egui-winit -p eframe --all-targets
--all-features -- -D warnings` ✅
- `cargo doc --lib --no-deps -p egui -p egui-winit -p eframe
--all-features` ✅
- `cargo check -p egui --no-default-features --features serde` ✅
(validates the `serde(skip)` on `cursor_image`)
- Interactive validation on Linux/Wayland with the OneAmp WSZ skin
player — see screenshots above.
I haven't run the full snapshot test suite (`scripts/check.sh`) because
we're on Linux and the snapshots are macOS-rendered — happy to run it if
you'd like.
## Notes
Drafted per the contributing guide ("open a draft PR, you may get
helpful feedback early"). Open to design feedback on:
1. Whether `CustomCursorImage` should live in `egui::viewport` rather
than `egui::data::output`.
2. Whether the legacy `handle_platform_output` should grow `event_loop`
directly (breaking) instead of getting a sibling method (non-breaking,
what I did).
3. Whether to also wire it through eframe-web (probably not —
`wasm-bindgen-cursor` would need its own path).
---------
Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
## Related
* https://github.com/emilk/egui/pull/5851
* https://github.com/emilk/egui/pull/7988
## What
We want to make it easier to understand the lineage of a `Id` (which is
the parent `Id`, and the parent of that, etc?)
As a first step of that, we want to clarify the different between a
globally unique `Id`, and an `IdSalt`
I also introduced the `AsId` and `AsIdSalt` traits, which are
implemented of anything that implements `Hash` and `Debug`. The `Debug`
half of that is unused here, but will later be used in `Debug` builds to
produce a proper tree.
* Part of https://github.com/emilk/egui/issues/8180
So far, you've been able to move any `egui::Window` by dragging anywhere
on it. This makes sense on touch screens with thick fingers, but less so
on non-touch-screens.
With this PR, you can now control it with a new enum `WindowDrag`
* Part of https://github.com/emilk/egui/issues/8180
Drag-to-scroll is a must-have on touch-screens, since there is no other
way to scroll.
However, when you are not on a touch screens, it is more surprising than
useful.
### Related
* Closes#8134.
* Related to #5136.
Possibly fixes:
* #8123
* #5145
### What
We did not properly handle the variants of
[`CurrentSurfaceTexture`](https://docs.rs/wgpu/latest/wgpu/enum.CurrentSurfaceTexture.html)
and always returned `SkipFrame`.
Because of this `egui` could end up in a state where frames are always
skipped after observing `Outdated`, without the chance to recover
(unless an event arrives from the outside).
> [!NOTE]
> This is not Wayland-specific, but could happen on all platforms. It
just happens frequently for Wayland compositors that directly resize a
window after creation (such as tiling/scrolling compositors like
`hyprland` and `niri`).
This PR improves this by separating the code paths for `Outdated` and
`Lost`, to help recover from those events.
## Related
* https://github.com/emilk/egui/issues/8043
* Introduced in #8103
## What
I noticed resizing the native winit window was really choppy and bad on
macOS, and this was the readon
* part of #7264
* based on https://github.com/emilk/egui/pull/8152
The resize fix allows use to really simplify how the Window Titlebar is
rendered. Previously it was using some complex flow to calculate and
allocate the height first and then render it later once we knew the
windows final width.
Since now windows can't shrink past their minimum content widths, I can
just show the titlebar inline with the regular content, just outside of
the `Resize` container so that it is always visible.
This does change what the size of a window means. Before, size was just
the size of the contents, while now size (e.g. via min_height) will
include the Frames margin and outline, title bar and the contents.
Also, the window label now truncates as you shrink the window (meaning
windows can now be smaller than their label allows).
---------
Co-authored-by: lucasmerlin <8009393+lucasmerlin@users.noreply.github.com>
This allows the base egui crate to run on platforms without 64 bit
atomics
* Addresses <https://github.com/emilk/egui/issues/7692>, but does not
address the `egui_extras` crate
* [x] I have followed the instructions in the PR template
* Closes part of <https://github.com/emilk/egui/issues/3284>
Add a class system toward a CSS-like styling.
Widget and Ui can implement the trait `HasClasses` which can be used
later by theme engines to compute a style based on the set of classes
the component has.
---------
Co-authored-by: adrien <221212@umons.ac.be>
Co-authored-by: Adrien Zianne <adrien@iq002.ipa.iqrypto.com>
Co-authored-by: lucasmerlin <hi@lucasmerlin.me>
Fixes some bugs that happen randomly when resizing horizontal_wrapped
texts:
https://github.com/user-attachments/assets/141392d2-0239-465a-ba7b-c864f7823319
Adds regression tests (I enjoy using claude to fix these bugs, first
have it create a minimal repro test case, then fix the bug by iterating
until it figures out a fix).
* [x] I have followed the instructions in the PR template
```
+ echo 'All checks passed.'
All checks passed.
```
I had to update `.png`'s for tests to pass, but I guess it's specific to
my laptop.
---------
Co-authored-by: Emil Ernerfeldt <emil.ernerfeldt@gmail.com>
This lets you start up the test app from within the test itself, which
can be very useful when you have a specific test scenario set up that
you need to debug.
### Related
* Previous attempt: https://github.com/emilk/egui/pull/5418
### macOS
On macOS, you may only run UIs on the main loop, so you need a few
additional steps. Not ideal, but works!
```diff
diff --git a/crates/egui_demo_app/Cargo.toml b/crates/egui_demo_app/Cargo.toml
index f9a153268..4e0cc14ee 100644
--- a/crates/egui_demo_app/Cargo.toml
+++ b/crates/egui_demo_app/Cargo.toml
@@ -84,3 +84,7 @@ web-sys.workspace = true
[dev-dependencies]
egui_kittest = { workspace = true, features = ["eframe", "snapshot", "wgpu"] }
+
+[[test]]
+name = "test_demo_app"
+harness = false
diff --git a/crates/egui_demo_app/tests/test_demo_app.rs b/crates/egui_demo_app/tests/test_demo_app.rs
index e083c8455..7ad9ed516 100644
--- a/crates/egui_demo_app/tests/test_demo_app.rs
+++ b/crates/egui_demo_app/tests/test_demo_app.rs
@@ -4,7 +4,10 @@ use egui_demo_app::{Anchor, WrapApp};
use egui_kittest::SnapshotResults;
use egui_kittest::kittest::Queryable as _;
-#[test]
+fn main() {
+ test_demo_app();
+}
+
fn test_demo_app() {
let mut harness = egui_kittest::Harness::builder()
.with_size(Vec2::new(900.0, 600.0))
@@ -73,5 +76,8 @@ fn test_demo_app() {
harness.run_steps(4);
results.add(harness.try_snapshot(anchor.to_string()));
+
+ harness.spawn_eframe_app();
+ break;
}
}
```
This is a breaking public API change, but is otherwise trivial due to it
not changing any actual runtime behaviour.
This renames eframe's NativeOptions `vsync` option to `glow_vsync` to
make clear without even looking at docs fully that this is specific to
the `glow` backend.
While I think a better option would actually be to change the wgpu
creation options to match the vsync option if not specified (either to
`AutoVsync` or `AutoNoVsync` depending on setting) this would require
this be made an `Option<PresentMode>`, which would be confusing - and
the `WgpuConfiguration` should probably take priority over other options
here, as there's more than 2 present modes that are relevant. So I think
this is a suitable way to go.
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* This does not close an issue - this was a trivial amount of code to
change, so I might as well just make it a PR on the spot.
* [x] I have followed the instructions in the PR template
---------
Co-authored-by: Emil Ernerfeldt <emil.ernerfeldt@gmail.com>
Let apps change present_mode and desired_maximum_frame_latency at
runtime instead of only at startup.
API changes (egui-wgpu):
- New SurfaceConfig { present_mode, desired_maximum_frame_latency }.
- WgpuConfiguration now nests these as pub surface: SurfaceConfig (was
two top-level fields).
- RenderState gains pub surface_config: SurfaceConfig — the
currently-requested value.
API additions (eframe):
- Frame::wgpu_surface_config() / Frame::set_wgpu_surface_config(...) for
get/set.
- SurfaceConfig re-exported as eframe::SurfaceConfig.
How it works:
The wgpu painter compares render_state.surface_config to its
currently-applied values each paint. If they differ it updates its
config and flips
needs_reconfigure on every surface, piggybacking on the existing
deferred-reconfigure pathway.
Demo:
The backend panel (egui_demo_app) gets dropdowns for present mode and
desired max frame latency, wired through the new Frame accessors.
<img width="282" height="172" alt="image"
src="https://github.com/user-attachments/assets/0b1274b2-7e4e-4413-969b-0a014c415f79"
/>
When enabled, trailing whitespace is included in the row width used for
horizontal alignment. This is useful for text editors where hiding
trailing spaces feels wrong when typing.
By default this is `false`, preserving existing behavior where trailing
whitespace is stripped for alignment (so "Hello " centers the same as
"Hello").
* follow up to https://github.com/emilk/egui/pull/8082
May close#8087, but cannot test macOS builtin Japanese IME.
## Summary
PR #8031 (harfrust text shaping) introduced a regression: when harfrust
shapes multi-codepoint clusters (flag emojis, ligatures, combining
marks) into fewer glyphs than input characters, the invariant
`glyphs.len() == char_count` breaks. This causes IME composition to
duplicate characters and text selection to behave incorrectly.
## Fix
In `layout_shaped_run()`, after emitting shaped glyphs for a cluster, we
now check if the cluster had more characters than glyphs. If so,
zero-width "continuation" glyphs are emitted for the extra characters,
restoring the 1:1 glyph-to-character mapping.
Continuation glyphs have `UvRect::default()` (`is_nothing() == true`),
so `tessellate_glyphs` skips them entirely. Background, underline, and
strikethrough rendering handle zero-width glyphs naturally.
Only `crates/epaint/src/text/text_layout.rs` is modified. No changes to
cursor logic, selection code, or public API.
## Test plan
- [x] `cargo fmt --all -- --check`
- [x] `cargo clippy -p epaint --tests`
- [x] `cargo test -p epaint -p egui` (all pass)
- [x] New test `test_grapheme_cluster_glyph_count`: verifies glyph count
== char count for flag emojis, combining marks, and plain ASCII
- [x] New test `test_grapheme_cluster_cursor_roundtrip`: verifies cursor
position stability through `pos_from_cursor` -> `cursor_from_pos`
round-trips on text containing flag emojis
- [x] Manual testing with demo app: selection and cursor navigation work
correctly on `A🇯🇵B`
- [ ] IME testing (macOS Japanese IME) needs to be validated by someone
on macOS
---
**This PR was developed with the assistance of Claude Code.**
---------
Co-authored-by: Emil Ernerfeldt <emil.ernerfeldt@gmail.com>
## Summary
`next_word_boundary_char_index` calls `char_index_from_byte_index` on
every word-boundary segment. Since `char_index_from_byte_index` scans
from the start of the string each time, this makes the function O(n·m)
where m is the number of segments — effectively O(n²) for large texts.
The fix replaces those repeated scans with a running char counter
maintained as we iterate segments. Same results, O(n) instead of O(n²).
## The problem
Any pointer interaction (click, double-click, drag) inside a `TextEdit`
with a large text buffer triggers `pointer_interaction` →
`select_word_at` → `ccursor_previous_word` →
`next_word_boundary_char_index`. On a 500 KB buffer this takes ~30
seconds, freezing the application.
## Benchmark results
Measured with cursor near end of text (worst case):
| Text size | Before | After | Speedup |
|-----------|--------|-------|---------|
| 1 KB | 147 µs | 38 µs | 3.9x |
| 100 KB | 1.2 s | 3.8 ms | 313x |
| 500 KB | 30 s | 18 ms | 1,636x |
Benchmark source:
[`bench/word-boundary-perf`](https://github.com/hallyhaa/egui/tree/bench/word-boundary-perf)
(separate branch, not part of this PR)
## Changes
- `next_word_boundary_char_index`: replace `char_index_from_byte_index`
calls with a `running_ci` counter (the fix — 6 changed lines)
- New tests for `ccursor_previous_word`, `ccursor_next_word`,
`select_word_at`, and a large-text performance test
---------
Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
**Perf: Optimize text selection and navigation performance for large
documents**
#### **Summary**
This PR significantly improves the performance of text selection
(double-clicking) and cursor navigation within `TextEdit` and `Label`
widgets, particularly when handling large documents (e.g., 1MB+ or
logs). It eliminates several $O(N^2)$ bottlenecks and unnecessary memory
allocations in `text_cursor_state.rs`.
#### **Problems Identified**
1. **$O(N^2)$ Word Boundary Scanning:** In
`next_word_boundary_char_index`, `char_index_from_byte_index` was called
repeatedly inside a loop. This caused the entire document to be scanned
from the beginning for every word found, leading to quadratic time
complexity.
2. **Heavy String Allocations:** `ccursor_previous_word` used
`collect::<String>()` and `rev()` to search backwards, causing a full
copy and memory allocation of the text (or line) every time the user
moved the cursor or double-clicked.
3. **Inefficient Line Start Finding:** `find_line_start` performed
global character counts (`text.chars().count()`) and global skips, which
is very slow for large files.
4. **Global Search Scope:** `select_word_at` was performing word
boundary searches across the entire document even for simple
double-click actions.
#### **Key Changes & Optimizations**
1. **Line-Scoped Selection:** Updated `select_word_at` to first identify
the current line and then perform word boundary searches within that
local scope. This reduces the search space from millions of characters
to hundreds.
2. **Linear Time ($O(N)$) Boundary Search:** Refactored
`next_word_boundary_char_index` to use a running cumulative character
counter. This ensures the text is scanned only once.
3. **Zero-Allocation Backwards Search:** Optimized
`ccursor_previous_word` to use `next_back()` on the
`DoubleEndedIterator` provided by `unicode-segmentation`. This removes
all temporary `String` allocations.
4. **Byte-Based Line Search:** Optimized `find_line_start` to use
byte-based reverse scanning (`rfind('\n')`), which is significantly
faster than counting characters from the start of the document.
#### **Performance Impact**
In my tests with large text files (over 10,000 lines / 1MB+):
- **Before:** Double-clicking a word caused a UI freeze for 2–5 seconds.
- **After:** Word selection and navigation are near-instantaneous
(0–1ms), providing a smooth "native-like" experience even in WASM
environments.
A couple improvements to centered and right-aligned text edits:
- Fix text selection in centered and right aligned text edits
(ironically, this broke in #8076)
- Fix cursor movement in centered and right aligned text edits
(horizontal cursor position will be retained on vertical movement)
- Multiline text edit exceeding available width if there are atoms
- Added atoms & alignment options to text edit demo
- Improve how vertical_align and horizontal_align are applied
- Textedit atom is grow now, removing the need for the extra seperate
grow atom
- This allows us to apply the `align` on the text edit atom instead of
the whole AtomLayout
- Fixes https://github.com/emilk/egui/pull/8022
- Fixes https://github.com/emilk/egui/issues/7999
