Crate eframe

Expand description

eframe - the egui framework crate

If you are planning to write an app for web or native, and want to use egui for everything, then eframe is for you!

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!

In short, you implement App (especially App::update) and then call crate::run_native from your main.rs, and/or use eframe::WebRunner from your lib.rs.

§Compiling for web

You need to install the wasm32 target with rustup target add wasm32-unknown-unknown.

Build the .wasm using cargo build --target wasm32-unknown-unknown and then use wasm-bindgen to generate the JavaScript glue code.

See the eframe_template repository for more.

§Simplified usage

If your app is only for native, and you don’t need advanced features like state persistence, then you can use the simpler function run_simple_native.

§Usage, native:

use eframe::egui;

fn main() {
    let native_options = eframe::NativeOptions::default();
    eframe::run_native("My egui App", native_options, Box::new(|cc| Ok(Box::new(MyEguiApp::new(cc)))));
}

#[derive(Default)]
struct MyEguiApp {}

impl MyEguiApp {
    fn new(cc: &eframe::CreationContext<'_>) -> Self {
        // Customize egui here with cc.egui_ctx.set_fonts and cc.egui_ctx.set_visuals.
        // Restore app state using cc.storage (requires the "persistence" feature).
        // Use the cc.gl (a glow::Context) to create graphics shaders and buffers that you can use
        // for e.g. egui::PaintCallback.
        Self::default()
    }
}

impl eframe::App for MyEguiApp {
   fn update(&mut self, ctx: &egui::Context, frame: &mut eframe::Frame) {
       egui::CentralPanel::default().show(ctx, |ui| {
           ui.heading("Hello World!");
       });
   }
}

§Usage, web:

use wasm_bindgen::prelude::*;

/// Your handle to the web app from JavaScript.
#[derive(Clone)]
#[wasm_bindgen]
pub struct WebHandle {
    runner: eframe::WebRunner,
}

#[wasm_bindgen]
impl WebHandle {
    /// Installs a panic hook, then returns.
    #[allow(clippy::new_without_default)]
    #[wasm_bindgen(constructor)]
    pub fn new() -> Self {
        // Redirect [`log`] message to `console.log` and friends:
        eframe::WebLogger::init(log::LevelFilter::Debug).ok();

        Self {
            runner: eframe::WebRunner::new(),
        }
    }

    /// Call this once from JavaScript to start your app.
    #[wasm_bindgen]
    pub async fn start(&self, canvas: web_sys::HtmlCanvasElement) -> Result<(), wasm_bindgen::JsValue> {
        self.runner
            .start(
                canvas,
                eframe::WebOptions::default(),
                Box::new(|cc| Ok(Box::new(MyEguiApp::new(cc))),)
            )
            .await
    }

    // The following are optional:

    /// Shut down eframe and clean up resources.
    #[wasm_bindgen]
    pub fn destroy(&self) {
        self.runner.destroy();
    }

    /// Example on how to call into your app from JavaScript.
    #[wasm_bindgen]
    pub fn example(&self) {
        if let Some(app) = self.runner.app_mut::<MyEguiApp>() {
            app.example();
        }
    }

    /// The JavaScript can check whether or not your app has crashed:
    #[wasm_bindgen]
    pub fn has_panicked(&self) -> bool {
        self.runner.has_panicked()
    }

    #[wasm_bindgen]
    pub fn panic_message(&self) -> Option<String> {
        self.runner.panic_summary().map(|s| s.message())
    }

    #[wasm_bindgen]
    pub fn panic_callstack(&self) -> Option<String> {
        self.runner.panic_summary().map(|s| s.callstack())
    }
}

§Feature flags

accesskit (enabled by default) — Enable platform accessibility API implementations through AccessKit.
android-game-activity — Enable the game-activity backend via egui-winit on Android
android-native-activity — Enable the native-activity backend via egui-winit on Android
default_fonts (enabled by default) — If set, egui will use include_bytes! to bundle some fonts. If you plan on specifying your own fonts you may disable this feature.
glow (enabled by default) — Use glow for painting, via egui_glow.
persistence — Enable saving app state to disk.
wayland (enabled by default) — Enables wayland support and fixes clipboard issue.
web_screen_reader (enabled by default) — Enable screen reader support (requires ctx.options_mut(|o| o.screen_reader = true);) on web.

For other platforms, use the accesskit feature instead.
wgpu — Use wgpu for painting (via egui-wgpu).

This overrides the glow feature.

By default, only WebGPU is enabled on web. If you want to enable WebGL, you need to turn on the webgl feature of crate wgpu:
```
wgpu = { version = "*", features = ["webgpu", "webgl"] }
```
By default, eframe will prefer WebGPU over WebGL, but you can configure this at run-time with [NativeOptions::wgpu_options].
x11 (enabled by default) — Enables compiling for x11.
__screenshot — If set, eframe will look for the env-var EFRAME_SCREENSHOT_TO and write a screenshot to that location, and then quit. This is used to generate images for examples.

§Instrumentation

This crate supports using the profiling crate for instrumentation. You can enable features on the profiling crates in your application to add instrumentation for all crates that support it, including egui. See the profiling crate docs for more information.

[dependencies]
profiling = "1.0"
[features]
profile-with-puffin = ["profiling/profile-with-puffin"]

Re-exports§

pub use egui;
pub use egui::emath;
pub use egui::epaint;
pub use egui_glow;
pub use glow;

Modules§

icon_data: Helpers for loading egui::IconData.

Structs§

CreationContext: Data that is passed to AppCreator that can be used to setup and initialize your app.
EventLoopBuilder: Object that allows building the event loop.
Frame: Represents the surroundings of your app.
IntegrationInfo: Information about the integration passed to the use app each frame.
NativeOptions: Options controlling the behavior of a native window.
WindowAttributes: Attributes used when creating a window.

Enums§

Error: The different problems that can occur when trying to run eframe.
HardwareAcceleration: Selects the level of hardware graphics acceleration.
Renderer: What rendering backend to use.
UserEvent: The custom even eframe uses with the winit event loop.
WebGlContextOption: WebGL Context options

Constants§

APP_KEY: Storage key used for app

Traits§

App: Implement this trait to write apps that can be compiled for both web/wasm and desktop/native using eframe.
Storage: A place where you can store custom data in a way that persists when you restart the app.

Functions§

run_native: This is how you start a native (desktop) app.
run_simple_native: The simplest way to get started when writing a native app.

Type Aliases§

AppCreator: This is how your app is created.
EventLoopBuilderHook: Hook into the building of an event loop before it is run
Result: Short for Result<T, eframe::Error>.
WindowBuilderHook: Hook into the building of a the native window.

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