fb92434aac
* eframe: allow hooking into EventLoop building This enables native applications to add an `event_loop_builder` callback to the `NativeOptions` struct that lets them modify the Winit `EventLoopBuilder` before the final `EventLoop` is built and run. This makes it practical for applications to change platform specific config options that Egui doesn't need to be directly aware of. For example the `android-activity` glue crate that supports writing Android applications in Rust requires that the Winit event loop be passed a reference to the `AndroidApp` that is given to the `android_main` entrypoint for the application. Since the `AndroidApp` itself is abstracted by Winit then there's no real need for Egui/EFrame to have a dependency on the `android-activity` crate just for the sake of associating this state with the event loop. Addresses: #1951 * eframe: defer graphics state initialization until app Resumed Conceptually the Winit `Resumed` event signifies that the application is ready to run and render and since https://github.com/rust-windowing/winit/pull/2331 all platforms now consistently emit a Resumed event that can be used to initialize graphics state for an application. On Android in particular it's important to wait until the application has Resumed before initializing graphics state since it won't have an associated SurfaceView while paused. Without this change then Android applications are likely to just show a black screen. This updates the Wgpu+Winit and Glow+Winit integration for eframe but it's worth noting that the Glow integration is still not able to fully support suspend and resume on Android due to limitations with Glutin's API that mean we can't destroy and create a Window without also destroying the GL context, and therefore (practically) the entire application. There is a plan (and progress on) to improve the Glutin API here: https://github.com/rust-windowing/glutin/pull/1435 and with that change it should be an incremental change to enable Android suspend/resume support with Glow later. In the mean time the Glow changes keep the implementation consistent with the wgpu integration and it should now at least be possible to start an Android application - even though it won't be able to suspend correctly. Fixes #1951 |
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| CHANGELOG.md | ||
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eframe: the egui framework
eframe is the official framework library for writing apps using egui. The app can be compiled both to run natively (cross platform) or be compiled to 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 libspeechd-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.
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.
Problems with 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.
- 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). - No integration with browser settings for colors and fonts.
- On Linux and Mac, Firefox will copy the WebGL render target from GPU, to CPU and then back again (https://bugzilla.mozilla.org/show_bug.cgi?id=1010527#c0), slowing down egui.
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" (frame is a framework, egui is a library).