759c8fd2c9
Currently, if the size of the canvas element changes independently of
the size of the browser window (e.g. due to its parent element
shrinking), then no repaints are scheduled.
This PR replaces the `resize` event with a `ResizeObserver`, which
ensures that _any_ resize of the canvas element (including those caused
by browser window resizes) trigger a repaint. The repaint is done
synchronously as part of the resize event, to reduce any potential
flickering.
The result seems to pass the rendering tests on most platform+browser
combinations. We tested:
- Chrome, Firefox, Safari on macOS
- Chrome, Firefox on Linux (ubuntu and arch, both running wayland)
- Chrome, Firefox on Windows
Firefox still has some antialiasing issues on Linux platforms, but this
antialiasing also happens on `master`, so this PR is not a regression
there.
The code setting `canvas.style.width` and `canvas.style.height` at the
start of `AppRunner::logic` was also removed - the canvas _display_ size
is now fully controlled by CSS, e.g. by setting `canvas { width: 100%;
height: 100%; }`.
The approach used here is described in
https://webglfundamentals.org/webgl/lessons/webgl-resizing-the-canvas.html
Note: The only remaining place where egui updates the style of the
canvas it is rendering to is some of the IME/mobile input handling code.
Fixing that is out of scope for this PR, and will be done in a followup
PR.
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| data | ||
| src | ||
| CHANGELOG.md | ||
| Cargo.toml | ||
| README.md | ||
README.md
eframe: the egui framework
eframe is the official framework library for writing apps using egui. The app can be compiled both to run natively (for Linux, Mac, Windows, and Android) or as a web app (using Wasm).
To get started, see the examples.
To learn how to set up eframe for web and native, go to https://github.com/emilk/eframe_template/ and follow the instructions there!
There is also a tutorial video at https://www.youtube.com/watch?v=NtUkr_z7l84.
For how to use egui, see the egui docs.
eframe uses egui_glow for rendering, and on native it uses egui-winit.
To use on Linux, first run:
sudo apt-get install libxcb-render0-dev libxcb-shape0-dev libxcb-xfixes0-dev libxkbcommon-dev libssl-dev
You need to either use edition = "2021", or set resolver = "2" in the [workspace] section of your to-level Cargo.toml. See this link for more info.
You can opt-in to the using egui_wgpu for rendering by enabling the wgpu feature and setting NativeOptions::renderer to Renderer::Wgpu.
To get copy-paste working on web, you need to compile with export RUSTFLAGS=--cfg=web_sys_unstable_apis.
Alternatives
eframe is not the only way to write an app using egui! You can also try egui-miniquad, bevy_egui, egui_sdl2_gl, and others.
You can also use egui_glow and winit to build your own app as demonstrated in https://github.com/emilk/egui/blob/master/crates/egui_glow/examples/pure_glow.rs.
Limitations when running egui on the web
eframe uses WebGL (via glow) and Wasm, and almost nothing else from the web tech stack. This has some benefits, but also produces some challenges and serious downsides.
- Rendering: Getting pixel-perfect rendering right on the web is very difficult.
- Search: you cannot search an egui web page like you would a normal web page.
- Bringing up an on-screen keyboard on mobile: there is no JS function to do this, so
eframefakes it by adding some invisible DOM elements. It doesn't always work. - Mobile text editing is not as good as for a normal web app.
- No integration with browser settings for colors and fonts.
- Accessibility: There is an experimental screen reader for
eframe, but it has to be enabled explicitly. There is no JS function to ask "Does the user want a screen reader?" (and there should probably not be such a function, due to user tracking/integrity concerns).eguisupports AccessKit, but as of early 2024, AccessKit lacks a Web backend.
In many ways, eframe is trying to make the browser do something it wasn't designed to do (though there are many things browser vendors could do to improve how well libraries like egui work).
The suggested use for eframe are for web apps where performance and responsiveness are more important than accessibility and mobile text editing.
Companion crates
Not all rust crates work when compiled to Wasm, but here are some useful crates have been designed to work well both natively and as Wasm:
Name
The frame in eframe stands both for the frame in which your egui app resides and also for "framework" (eframe is a framework, egui is a library).