egui Files

egui is an easy-to-use immediate mode GUI for Rust that runs on both web and native.

Try it now: https://www.egui.rs/

egui development is sponsored by Rerun, a startup building an SDK for visualizing streams of multimodal data.

Highlights

• New egui_mcp crate based on eguis new inspection protocol
• Set classes on your Uis to modify widget behavior based on surrounding context
• Improved IME

Egui inspection and egui_mcp

This release includes a new inspection protocol for egui. It allows reading the accesskit tree of a running app, as well as sending events to control it. It's implemented via a new InspectionPlugin in the egui_inspection crate. Eframe includes a new inspection feature. When enabled, you can enable inspection by launching the app with EGUI_INSPECTION=1. This will cause the app to listen on port 5719.

The first inspection protocol consumer is egui_mcp. It's a mcp server that allows your agent to see and use egui apps. It can be used to have the agent use the app, reproduce bugs and verify its changes. Install it via cargo install --git https://github.com/rerun-io/kittest_inspector egui_mcp and then add it to your agent via claude mcp add egui egui-mcp.

There is also a plan of adding a general inspection gui using the same protocol, that can e.g. be used to step through kittest tests frame by frame.

Here is claude using the mcp to try some of the egui demos (sped up by a lot, claude is slow):

https://github.com/user-attachments/assets/c3dd0456-acfc-428c-8efe-f4a244c9e3ba

• Add egui_inspection protocol and plugin #8234 by @lucasmerlin

Classes

As part of css like styling, we've added classes to egui. You can already use them to e.g. modify widget behavior or styling based on surrounding context. Add classes to the container:

:::rs
ui.scope_builder(UiBuilder::new().with_class("my_container"), |ui| {
    ...
});

In your widget, check if we're in my_container, to e.g. change sizes or colors:

:::rs
  let in_container = ui.stack().iter().any(|s| s.classes.has("my_container"));

Today this only works for custom widgets and ui code, but the next step will be a styling system that allows you to modify built in widget styling based on these classes.

• Add Classes to UiBuilder and some Widgets #7843 by @AdrienZianne

Better IME composition

IME visuals received an overhaul, they are now indicated by an underline and properly show the cursor during composition:

https://github.com/user-attachments/assets/487c7e7c-ef6d-4a86-8dbc-8c71871b4470

• Implement proper visuals for IME composition #8083 by @umajho

⭐ Added

• Add Classes to UiBuilder and some Widgets #7843 by @AdrienZianne
• Drag-to-close panels #8182 by @emilk
• Add AtomKind::Layout, for nesting AtomLayout #8219 by @lucasmerlin
• Add AtomLayout::direction #8221 by @lucasmerlin
• Make the size of tabs and thin space configurable #8070 by @emilk
• Add subpixel_binning to TextOptions and FontTweak #8072 by @emilk
• Allow Atoms in Ui::small_button #8159 by @lucasmerlin
• Atom support for egui::Window Titlebar #8154 by @lucasmerlin
• Add AsId and IdSalt #8184 by @emilk
• Add Context::set_cursor_image for OS-level custom cursors #8155 by @all3f0r1
• Add ViewportBuilder::with_monitor + ViewportCommand::SetMonitor #8140 by @Le-Syl21
• Add modifier keys to egui::Key #8127 by @Le-Syl21
• Expose interactive rects from the last pass #8211 by @psyche314
• Add AtomLayout::selectable for opt-in text selection #8224 by @akagifreeez
• Add LayoutJob::format_at_byte #8244 by @emilk
• Add atoms() helpers to get Atoms from widgets #8128 by @Nashvill375

🔧 Changed

• Improve IME handling, add public method owns_ime_events on Memory #7983 by @umajho
• Use harfrust for better kerning and ligatures #8031 by @gcailly
• Rework Window margins and set clip_rect_margin to zero #7725 by @emilk
• Slide panels when animating them #8175 by @emilk
• Slow down animation time from 0.1s to 0.2s #8176 by @emilk
• Smoother CollapsingHeader animation #8177 by @emilk
• Drag-to-scroll: now only on touch screens #8181 by @emilk
• Window: move only by dragging title bar #8183 by @emilk
• Rename Panel methods #8192 by @emilk
• Panels: double-click resize edge to toggle #8193 by @emilk
• Rename AlphaFromCoverage to FontColorTransferFunction #8201 by @emilk
• Smoother collapsed-panel animation #8202 by @emilk
• Improve Debug-formatting of Id in debug-builds #8190 by @emilk
• Use strongly typed CharIndex and ByteIndex + bug fixes #8245 by @emilk
• Allow downscaling image in GetScreenshot inspection request #8248 by @lucasmerlin
• Announce pressed state of selectable buttons to screen readers #8130 by @antoinecellerier
• Pre-populate font variation axes in the FontTweak UI #8258 by @emilk
• Make font hinting target configurable via FontTweak #8262 by @emilk

🔥 Removed

• Remove everything that was marked #[deprecated] #8105 by @emilk
• Remove 64-bit atomics in main crate #8037 by @kay-lambdadelta
• Remove impl Into<f32> arguments #8194 by @emilk

🐛 Fixed

• Don't hide whitespaces in centered and right aligned text edits #8102 by @lucasmerlin
• Don't allow resizing past minimum content size #8152 by @lucasmerlin
• Fix resizing of Grid #8170 by @lucasmerlin
• Fix glyph caching on font variations #8189 by @emilk
• Panel: never overflow available width, nor max_width #8198 by @emilk
• Fixes color picker hue drift at low alpha values #8208 by @aedm
• Fix: ScrollArea layout jitter with floating bars and zoom levels #7944 by @rustbasic
• Fix [#2142] - lost_focus not firing after a mid-frame focus transfer #8210 by @ufoscout
• Fix label selection in deferred viewports #8242 by @yay