Crate eframe

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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

To get copy-paste working on web, you need to compile with export RUSTFLAGS=--cfg=web_sys_unstable_apis.

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| 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_id: &str) -> Result<(), wasm_bindgen::JsValue> {
        self.runner
            .start(
                canvas_id,
                eframe::WebOptions::default(),
                Box::new(|cc| 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.

  • puffin — Enable profiling with the puffin crate.

    eframe will call puffin::GlobalProfiler::lock().new_frame() for you

    Only enabled on native, because of the low resolution (1ms) of clocks in browsers.

  • 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.

Re-exports§

Modules§

Structs§

Enums§

Constants§

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§

  • get_value
    Get and deserialize the RON stored at the given key.
  • 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.
  • set_value
    Serialize the given value as RON and store with the given key.
  • storage_dir
    The folder where eframe will store its state.

Type Aliases§