Refactor integrations (#871)

* Unify code in egui_glium and egui_glow into egui_winit::EpiIntegration
* Simplify `EguiGlium` interface
* Simplify `EguiGlow` interface
* egui_web refactor: merge `WebBackend` into `AppRunner`

egui-winit/CHANGELOG.md

@@ -4,9 +4,12 @@ All notable changes to the `egui-winit` integration will be noted in this file.
 
 
 ## Unreleased
+### Added ⭐
+* Add helper `EpiIntegration` ([#871](https://github.com/emilk/egui/pull/871)).
 
 ### Fixed 🐛
 * Fix shift key getting stuck enabled with the X11 option `shift:both_capslock` enabled ([#849](https://github.com/emilk/egui/pull/849)).
 
+
 ## 0.15.0 - 2021-10-24
 First stand-alone release. Previously part of `egui_glium`.

egui-winit/src/epi.rs

@@ -181,3 +181,157 @@ impl Persistence {
         }
     }
 }
+
+// ----------------------------------------------------------------------------
+
+/// Everything needed to make a winit-based integration for [`epi`].
+pub struct EpiIntegration {
+    integration_name: &'static str,
+    persistence: crate::epi::Persistence,
+    repaint_signal: std::sync::Arc<dyn epi::RepaintSignal>,
+    pub egui_ctx: egui::CtxRef,
+    egui_winit: crate::State,
+    pub app: Box<dyn epi::App>,
+    latest_frame_time: Option<f32>,
+    /// When set, it is time to quit
+    quit: bool,
+}
+
+impl EpiIntegration {
+    pub fn new(
+        integration_name: &'static str,
+        window: &winit::window::Window,
+        tex_allocator: &mut dyn epi::TextureAllocator,
+        repaint_signal: std::sync::Arc<dyn epi::RepaintSignal>,
+        persistence: crate::epi::Persistence,
+        app: Box<dyn epi::App>,
+    ) -> Self {
+        let egui_ctx = egui::CtxRef::default();
+
+        *egui_ctx.memory() = persistence.load_memory().unwrap_or_default();
+
+        let mut slf = Self {
+            integration_name,
+            persistence,
+            repaint_signal,
+            egui_ctx,
+            egui_winit: crate::State::new(window),
+            app,
+            latest_frame_time: None,
+            quit: false,
+        };
+
+        slf.setup(window, tex_allocator);
+        if slf.app.warm_up_enabled() {
+            slf.warm_up(window, tex_allocator);
+        }
+
+        slf
+    }
+
+    fn setup(
+        &mut self,
+        window: &winit::window::Window,
+        tex_allocator: &mut dyn epi::TextureAllocator,
+    ) {
+        let mut app_output = epi::backend::AppOutput::default();
+        let mut frame = epi::backend::FrameBuilder {
+            info: integration_info(self.integration_name, window, None),
+            tex_allocator,
+            output: &mut app_output,
+            repaint_signal: self.repaint_signal.clone(),
+        }
+        .build();
+        self.app
+            .setup(&self.egui_ctx, &mut frame, self.persistence.storage());
+
+        self.quit |= app_output.quit;
+
+        crate::epi::handle_app_output(window, self.egui_ctx.pixels_per_point(), app_output);
+    }
+
+    fn warm_up(
+        &mut self,
+        window: &winit::window::Window,
+        tex_allocator: &mut dyn epi::TextureAllocator,
+    ) {
+        let saved_memory = self.egui_ctx.memory().clone();
+        self.egui_ctx.memory().set_everything_is_visible(true);
+        self.update(window, tex_allocator);
+        *self.egui_ctx.memory() = saved_memory; // We don't want to remember that windows were huge.
+        self.egui_ctx.clear_animations();
+    }
+
+    /// If `true`, it is time to shut down.
+    pub fn should_quit(&self) -> bool {
+        self.quit
+    }
+
+    pub fn on_event(&mut self, event: &winit::event::WindowEvent<'_>) {
+        self.quit |= self.egui_winit.is_quit_event(event);
+        self.egui_winit.on_event(&self.egui_ctx, event);
+    }
+
+    /// Returns `needs_repaint` and shapes to paint.
+    pub fn update(
+        &mut self,
+        window: &winit::window::Window,
+        tex_allocator: &mut dyn epi::TextureAllocator,
+    ) -> (bool, Vec<egui::epaint::ClippedShape>) {
+        let frame_start = std::time::Instant::now();
+
+        let raw_input = self.egui_winit.take_egui_input(window);
+
+        self.egui_ctx.begin_frame(raw_input);
+
+        let mut app_output = epi::backend::AppOutput::default();
+        let mut frame = epi::backend::FrameBuilder {
+            info: integration_info(self.integration_name, window, self.latest_frame_time),
+            tex_allocator,
+            output: &mut app_output,
+            repaint_signal: self.repaint_signal.clone(),
+        }
+        .build();
+
+        self.app.update(&self.egui_ctx, &mut frame);
+
+        let (egui_output, shapes) = self.egui_ctx.end_frame();
+        let needs_repaint = egui_output.needs_repaint;
+        self.egui_winit
+            .handle_output(window, &self.egui_ctx, egui_output);
+
+        self.quit |= app_output.quit;
+
+        crate::epi::handle_app_output(window, self.egui_ctx.pixels_per_point(), app_output);
+
+        let frame_time = (std::time::Instant::now() - frame_start).as_secs_f64() as f32;
+        self.latest_frame_time = Some(frame_time);
+
+        (needs_repaint, shapes)
+    }
+
+    pub fn maybe_autosave(&mut self, window: &winit::window::Window) {
+        self.persistence
+            .maybe_autosave(&mut *self.app, &self.egui_ctx, window);
+    }
+
+    pub fn on_exit(&mut self, window: &winit::window::Window) {
+        self.app.on_exit();
+        self.persistence
+            .save(&mut *self.app, &self.egui_ctx, window);
+    }
+}
+
+fn integration_info(
+    integration_name: &'static str,
+    window: &winit::window::Window,
+    previous_frame_time: Option<f32>,
+) -> epi::IntegrationInfo {
+    epi::IntegrationInfo {
+        name: integration_name,
+        web_info: None,
+        prefer_dark_mode: None, // TODO: figure out system default
+        cpu_usage: previous_frame_time,
+        native_pixels_per_point: Some(crate::native_pixels_per_point(window)),
+    }
+}

egui-winit/src/lib.rs

@@ -171,7 +171,7 @@ impl State {
 
     /// Prepare for a new frame by extracting the accumulated input,
     /// as well as setting [the time](egui::RawInput::time) and [screen rectangle](egui::RawInput::screen_rect).
-    pub fn take_egui_input(&mut self, display: &winit::window::Window) -> egui::RawInput {
+    pub fn take_egui_input(&mut self, window: &winit::window::Window) -> egui::RawInput {
         let pixels_per_point = self.pixels_per_point();
 
         self.egui_input.time = Some(self.start_time.elapsed().as_secs_f64());
@@ -179,7 +179,7 @@ impl State {
         // On Windows, a minimized window will have 0 width and height.
         // See: https://github.com/rust-windowing/winit/issues/208
         // This solves an issue where egui window positions would be changed when minimizing on Windows.
-        let screen_size_in_pixels = screen_size_in_pixels(display);
+        let screen_size_in_pixels = screen_size_in_pixels(window);
         let screen_size_in_points = screen_size_in_pixels / pixels_per_point;
         self.egui_input.screen_rect =
             if screen_size_in_points.x > 0.0 && screen_size_in_points.y > 0.0 {

egui_glium/CHANGELOG.md

@@ -3,6 +3,7 @@ All notable changes to the `egui_glium` integration will be noted in this file.
 
 
 ## Unreleased
+* Simplify `EguiGlium` interface ([#871](https://github.com/emilk/egui/pull/871)).
 
 
 ## 0.15.0 - 2021-10-24

egui_glium/examples/native_texture.rs

@@ -41,7 +41,7 @@ fn main() {
     let event_loop = glutin::event_loop::EventLoop::with_user_event();
     let display = create_display(&event_loop);
 
-    let mut egui = egui_glium::EguiGlium::new(&display);
+    let mut egui_glium = egui_glium::EguiGlium::new(&display);
 
     let png_data = include_bytes!("../../eframe/examples/rust-logo-256x256.png");
     let image = load_glium_image(png_data);
@@ -51,24 +51,22 @@ fn main() {
     // Allow us to share the texture with egui:
     let glium_texture = std::rc::Rc::new(glium_texture);
     // Allocate egui's texture id for GL texture
-    let texture_id = egui.painter_mut().register_native_texture(glium_texture);
+    let texture_id = egui_glium.painter.register_native_texture(glium_texture);
 
     event_loop.run(move |event, _, control_flow| {
         let mut redraw = || {
-            egui.begin_frame(&display);
-
             let mut quit = false;
 
-            egui::SidePanel::left("my_side_panel").show(egui.ctx(), |ui| {
+            let (needs_repaint, shapes) = egui_glium.run(&display, |egui_ctx| {
-                ui.heading("");
+                egui::SidePanel::left("my_side_panel").show(egui_ctx, |ui| {
                     if ui.button("Quit").clicked() {
                         quit = true;
                     }
                 });
-            egui::Window::new("NativeTextureDisplay").show(egui.ctx(), |ui| {
+                egui::Window::new("NativeTextureDisplay").show(egui_ctx, |ui| {
                     ui.image(texture_id, image_size);
                 });
-            let (needs_repaint, shapes) = egui.end_frame(&display);
+            });
 
             *control_flow = if quit {
                 glutin::event_loop::ControlFlow::Exit
@@ -83,17 +81,12 @@ fn main() {
                 use glium::Surface as _;
                 let mut target = display.draw();
 
-                let clear_color = egui::Rgba::from_rgb(0.1, 0.3, 0.2);
+                let color = egui::Rgba::from_rgb(0.1, 0.3, 0.2);
-                target.clear_color(
+                target.clear_color(color[0], color[1], color[2], color[3]);
-                    clear_color[0],
-                    clear_color[1],
-                    clear_color[2],
-                    clear_color[3],
-                );
 
                 // draw things behind egui here
 
-                egui.paint(&display, &mut target, shapes);
+                egui_glium.paint(&display, &mut target, shapes);
 
                 // draw things on top of egui here
 
@@ -109,11 +102,11 @@ fn main() {
             glutin::event::Event::RedrawRequested(_) if !cfg!(windows) => redraw(),
 
             glutin::event::Event::WindowEvent { event, .. } => {
-                if egui.is_quit_event(&event) {
+                if egui_glium.is_quit_event(&event) {
                     *control_flow = glium::glutin::event_loop::ControlFlow::Exit;
                 }
 
-                egui.on_event(&event);
+                egui_glium.on_event(&event);
 
                 display.gl_window().window().request_redraw(); // TODO: ask egui if the events warrants a repaint instead
             }

egui_glium/examples/pure_glium.rs

@@ -23,22 +23,20 @@ fn main() {
     let event_loop = glutin::event_loop::EventLoop::with_user_event();
     let display = create_display(&event_loop);
 
-    let mut egui = egui_glium::EguiGlium::new(&display);
+    let mut egui_glium = egui_glium::EguiGlium::new(&display);
 
     event_loop.run(move |event, _, control_flow| {
         let mut redraw = || {
-            egui.begin_frame(&display);
-
             let mut quit = false;
 
-            egui::SidePanel::left("my_side_panel").show(egui.ctx(), |ui| {
+            let (needs_repaint, shapes) = egui_glium.run(&display, |egui_ctx| {
+                egui::SidePanel::left("my_side_panel").show(egui_ctx, |ui| {
                     ui.heading("Hello World!");
                     if ui.button("Quit").clicked() {
                         quit = true;
                     }
                 });
-
+            });
-            let (needs_repaint, shapes) = egui.end_frame(&display);
 
             *control_flow = if quit {
                 glutin::event_loop::ControlFlow::Exit
@@ -58,7 +56,7 @@ fn main() {
 
                 // draw things behind egui here
 
-                egui.paint(&display, &mut target, shapes);
+                egui_glium.paint(&display, &mut target, shapes);
 
                 // draw things on top of egui here
 
@@ -74,11 +72,11 @@ fn main() {
             glutin::event::Event::RedrawRequested(_) if !cfg!(windows) => redraw(),
 
             glutin::event::Event::WindowEvent { event, .. } => {
-                if egui.is_quit_event(&event) {
+                if egui_glium.is_quit_event(&event) {
                     *control_flow = glium::glutin::event_loop::ControlFlow::Exit;
                 }
 
-                egui.on_event(&event);
+                egui_glium.on_event(&event);
 
                 display.gl_window().window().request_redraw(); // TODO: ask egui if the events warrants a repaint instead
             }

egui_glium/src/epi_backend.rs

@@ -2,7 +2,6 @@ use crate::*;
 use egui::Color32;
 #[cfg(target_os = "windows")]
 use glium::glutin::platform::windows::WindowBuilderExtWindows;
-use std::time::Instant;
 
 impl epi::TextureAllocator for Painter {
     fn alloc_srgba_premultiplied(
@@ -45,85 +44,35 @@ fn create_display(
     glium::Display::new(window_builder, context_builder, event_loop).unwrap()
 }
 
-fn integration_info(
-    display: &glium::Display,
-    previous_frame_time: Option<f32>,
-) -> epi::IntegrationInfo {
-    epi::IntegrationInfo {
-        name: "egui_glium",
-        web_info: None,
-        prefer_dark_mode: None, // TODO: figure out system default
-        cpu_usage: previous_frame_time,
-        native_pixels_per_point: Some(egui_winit::native_pixels_per_point(
-            display.gl_window().window(),
-        )),
-    }
-}
-
 // ----------------------------------------------------------------------------
 
 pub use epi::NativeOptions;
 
 /// Run an egui app
-pub fn run(mut app: Box<dyn epi::App>, native_options: &epi::NativeOptions) -> ! {
+pub fn run(app: Box<dyn epi::App>, native_options: &epi::NativeOptions) -> ! {
-    let mut persistence = egui_winit::epi::Persistence::from_app_name(app.name());
+    let persistence = egui_winit::epi::Persistence::from_app_name(app.name());
-
     let window_settings = persistence.load_window_settings();
-    let event_loop = glutin::event_loop::EventLoop::with_user_event();
     let window_builder =
         egui_winit::epi::window_builder(native_options, &window_settings).with_title(app.name());
+    let event_loop = glutin::event_loop::EventLoop::with_user_event();
     let display = create_display(window_builder, &event_loop);
 
     let repaint_signal = std::sync::Arc::new(GliumRepaintSignal(std::sync::Mutex::new(
         event_loop.create_proxy(),
     )));
 
-    let mut egui = EguiGlium::new(&display);
+    let mut painter = crate::Painter::new(&display);
-    *egui.ctx().memory() = persistence.load_memory().unwrap_or_default();
+    let mut integration = egui_winit::epi::EpiIntegration::new(
-
+        "egui_glium",
-    {
+        display.gl_window().window(),
-        let (ctx, painter) = egui.ctx_and_painter_mut();
+        &mut painter,
-        let mut app_output = epi::backend::AppOutput::default();
+        repaint_signal,
-        let mut frame = epi::backend::FrameBuilder {
+        persistence,
-            info: integration_info(&display, None),
+        app,
-            tex_allocator: painter,
+    );
-            output: &mut app_output,
-            repaint_signal: repaint_signal.clone(),
-        }
-        .build();
-        app.setup(ctx, &mut frame, persistence.storage());
-    }
-
-    let mut previous_frame_time = None;
 
     let mut is_focused = true;
 
-    if app.warm_up_enabled() {
-        let saved_memory = egui.ctx().memory().clone();
-        egui.ctx().memory().set_everything_is_visible(true);
-
-        egui.begin_frame(&display);
-        let (ctx, painter) = egui.ctx_and_painter_mut();
-        let mut app_output = epi::backend::AppOutput::default();
-        let mut frame = epi::backend::FrameBuilder {
-            info: integration_info(&display, None),
-            tex_allocator: painter,
-            output: &mut app_output,
-            repaint_signal: repaint_signal.clone(),
-        }
-        .build();
-
-        app.update(ctx, &mut frame);
-
-        let _ = egui.end_frame(&display);
-
-        *egui.ctx().memory() = saved_memory; // We don't want to remember that windows were huge.
-        egui.ctx().clear_animations();
-
-        // TODO: handle app_output
-        // eprintln!("Warmed up in {} ms", warm_up_start.elapsed().as_millis())
-    }
-
     event_loop.run(move |event, _, control_flow| {
         let mut redraw = || {
             if !is_focused {
@@ -135,41 +84,29 @@ pub fn run(mut app: Box<dyn epi::App>, native_options: &epi::NativeOptions) -> !
                 std::thread::sleep(std::time::Duration::from_millis(10));
             }
 
-            let frame_start = std::time::Instant::now();
+            let (needs_repaint, shapes) =
-
+                integration.update(display.gl_window().window(), &mut painter);
-            egui.begin_frame(&display);
+            let clipped_meshes = integration.egui_ctx.tessellate(shapes);
-            let (ctx, painter) = egui.ctx_and_painter_mut();
-            let mut app_output = epi::backend::AppOutput::default();
-            let mut frame = epi::backend::FrameBuilder {
-                info: integration_info(&display, previous_frame_time),
-                tex_allocator: painter,
-                output: &mut app_output,
-                repaint_signal: repaint_signal.clone(),
-            }
-            .build();
-            app.update(ctx, &mut frame);
-            let (needs_repaint, shapes) = egui.end_frame(&display);
-
-            let frame_time = (Instant::now() - frame_start).as_secs_f64() as f32;
-            previous_frame_time = Some(frame_time);
 
             {
                 use glium::Surface as _;
                 let mut target = display.draw();
-                let color = app.clear_color();
+                let color = integration.app.clear_color();
                 target.clear_color(color[0], color[1], color[2], color[3]);
-                egui.paint(&display, &mut target, shapes);
+
+                painter.paint_meshes(
+                    &display,
+                    &mut target,
+                    integration.egui_ctx.pixels_per_point(),
+                    clipped_meshes,
+                    &integration.egui_ctx.texture(),
+                );
+
                 target.finish().unwrap();
             }
 
             {
-                egui_winit::epi::handle_app_output(
+                *control_flow = if integration.should_quit() {
-                    display.gl_window().window(),
-                    egui.ctx().pixels_per_point(),
-                    app_output.clone(),
-                );
-
-                *control_flow = if app_output.quit {
                     glutin::event_loop::ControlFlow::Exit
                 } else if needs_repaint {
                     display.gl_window().window().request_redraw();
@@ -179,7 +116,7 @@ pub fn run(mut app: Box<dyn epi::App>, native_options: &epi::NativeOptions) -> !
                 };
             }
 
-            persistence.maybe_autosave(&mut *app, egui.ctx(), display.gl_window().window());
+            integration.maybe_autosave(display.gl_window().window());
         };
 
         match event {
@@ -190,27 +127,23 @@ pub fn run(mut app: Box<dyn epi::App>, native_options: &epi::NativeOptions) -> !
             glutin::event::Event::RedrawRequested(_) if !cfg!(windows) => redraw(),
 
             glutin::event::Event::WindowEvent { event, .. } => {
-                if egui.is_quit_event(&event) {
-                    *control_flow = glium::glutin::event_loop::ControlFlow::Exit;
-                }
-
                 if let glutin::event::WindowEvent::Focused(new_focused) = event {
                     is_focused = new_focused;
                 }
 
-                egui.on_event(&event);
+                integration.on_event(&event);
+                if integration.should_quit() {
+                    *control_flow = glium::glutin::event_loop::ControlFlow::Exit;
+                }
 
                 display.gl_window().window().request_redraw(); // TODO: ask egui if the events warrants a repaint instead
             }
             glutin::event::Event::LoopDestroyed => {
-                app.on_exit();
+                integration.on_exit(display.gl_window().window());
-                persistence.save(&mut *app, egui.ctx(), display.gl_window().window());
             }
-
             glutin::event::Event::UserEvent(RequestRepaintEvent) => {
                 display.gl_window().window().request_redraw();
             }
-
             _ => (),
         }
     });

egui_glium/src/lib.rs

@@ -103,9 +103,9 @@ use glium::glutin;
 
 /// Use [`egui`] from a [`glium`] app.
 pub struct EguiGlium {
-    egui_ctx: egui::CtxRef,
+    pub egui_ctx: egui::CtxRef,
-    egui_winit: egui_winit::State,
+    pub egui_winit: egui_winit::State,
-    painter: crate::Painter,
+    pub painter: crate::Painter,
 }
 
 impl EguiGlium {
@@ -117,27 +117,6 @@ impl EguiGlium {
         }
     }
 
-    pub fn ctx(&self) -> &egui::CtxRef {
-        &self.egui_ctx
-    }
-
-    /// useful for calling e.g. [`crate::Painter::alloc_user_texture`].
-    pub fn painter_mut(&mut self) -> &mut crate::Painter {
-        &mut self.painter
-    }
-
-    pub fn ctx_and_painter_mut(&mut self) -> (&egui::CtxRef, &mut crate::Painter) {
-        (&self.egui_ctx, &mut self.painter)
-    }
-
-    pub fn pixels_per_point(&self) -> f32 {
-        self.egui_winit.pixels_per_point()
-    }
-
-    pub fn egui_input(&self) -> &egui::RawInput {
-        self.egui_winit.egui_input()
-    }
-
     /// Returns `true` if egui wants exclusive use of this event
     /// (e.g. a mouse click on an egui window, or entering text into a text field).
     /// For instance, if you use egui for a game, you want to first call this
@@ -153,35 +132,24 @@ impl EguiGlium {
         self.egui_winit.is_quit_event(event)
     }
 
-    pub fn begin_frame(&mut self, display: &glium::Display) {
-        let raw_input = self.take_raw_input(display);
-        self.begin_frame_with_input(raw_input);
-    }
-
-    pub fn begin_frame_with_input(&mut self, raw_input: egui::RawInput) {
-        self.egui_ctx.begin_frame(raw_input);
-    }
-
-    /// Prepare for a new frame. Normally you would call [`Self::begin_frame`] instead.
-    pub fn take_raw_input(&mut self, display: &glium::Display) -> egui::RawInput {
-        self.egui_winit
-            .take_egui_input(display.gl_window().window())
-    }
-
     /// Returns `needs_repaint` and shapes to draw.
-    pub fn end_frame(
+    pub fn run(
         &mut self,
         display: &glium::Display,
+        mut run_ui: impl FnMut(&egui::CtxRef),
     ) -> (bool, Vec<egui::epaint::ClippedShape>) {
+        let raw_input = self
+            .egui_winit
+            .take_egui_input(display.gl_window().window());
+        self.egui_ctx.begin_frame(raw_input);
+
+        run_ui(&self.egui_ctx);
+
         let (egui_output, shapes) = self.egui_ctx.end_frame();
         let needs_repaint = egui_output.needs_repaint;
-        self.handle_output(display, egui_output);
-        (needs_repaint, shapes)
-    }
-
-    pub fn handle_output(&mut self, display: &glium::Display, output: egui::Output) {
         self.egui_winit
-            .handle_output(display.gl_window().window(), &self.egui_ctx, output);
+            .handle_output(display.gl_window().window(), &self.egui_ctx, egui_output);
+        (needs_repaint, shapes)
     }
 
     pub fn paint<T: glium::Surface>(

egui_glow/CHANGELOG.md

@@ -3,6 +3,7 @@ All notable changes to the `egui_glow` integration will be noted in this file.
 
 
 ## Unreleased
+* Simplify `EguiGlow` interface ([#871](https://github.com/emilk/egui/pull/871)).
 
 
 ## 0.15.0 - 2021-10-24

egui_glow/examples/pure_glow.rs

@@ -40,22 +40,20 @@ fn main() {
     let event_loop = glutin::event_loop::EventLoop::with_user_event();
     let (gl_window, gl) = create_display(&event_loop);
 
-    let mut egui = egui_glow::EguiGlow::new(&gl_window, &gl);
+    let mut egui_glow = egui_glow::EguiGlow::new(&gl_window, &gl);
 
     event_loop.run(move |event, _, control_flow| {
         let mut redraw = || {
-            egui.begin_frame(gl_window.window());
-
             let mut quit = false;
 
-            egui::SidePanel::left("my_side_panel").show(egui.ctx(), |ui| {
+            let (needs_repaint, shapes) = egui_glow.run(gl_window.window(), |egui_ctx| {
+                egui::SidePanel::left("my_side_panel").show(egui_ctx, |ui| {
                     ui.heading("Hello World!");
                     if ui.button("Quit").clicked() {
                         quit = true;
                     }
                 });
-
+            });
-            let (needs_repaint, shapes) = egui.end_frame(gl_window.window());
 
             *control_flow = if quit {
                 glutin::event_loop::ControlFlow::Exit
@@ -76,7 +74,7 @@ fn main() {
 
                 // draw things behind egui here
 
-                egui.paint(&gl_window, &gl, shapes);
+                egui_glow.paint(&gl_window, &gl, shapes);
 
                 // draw things on top of egui here
 
@@ -92,7 +90,7 @@ fn main() {
             glutin::event::Event::RedrawRequested(_) if !cfg!(windows) => redraw(),
 
             glutin::event::Event::WindowEvent { event, .. } => {
-                if egui.is_quit_event(&event) {
+                if egui_glow.is_quit_event(&event) {
                     *control_flow = glutin::event_loop::ControlFlow::Exit;
                 }
 
@@ -100,12 +98,12 @@ fn main() {
                     gl_window.resize(physical_size);
                 }
 
-                egui.on_event(&event);
+                egui_glow.on_event(&event);
 
                 gl_window.window().request_redraw(); // TODO: ask egui if the events warrants a repaint instead
             }
             glutin::event::Event::LoopDestroyed => {
-                egui.destroy(&gl);
+                egui_glow.destroy(&gl);
             }
 
             _ => (),

egui_glow/src/epi_backend.rs

@@ -2,7 +2,6 @@ use crate::*;
 use egui::Color32;
 #[cfg(target_os = "windows")]
 use glutin::platform::windows::WindowBuilderExtWindows;
-use std::time::Instant;
 
 impl epi::TextureAllocator for Painter {
     fn alloc_srgba_premultiplied(
@@ -60,84 +59,36 @@ fn create_display(
     (gl_window, gl)
 }
 
-fn integration_info(
-    window: &glutin::window::Window,
-    previous_frame_time: Option<f32>,
-) -> epi::IntegrationInfo {
-    epi::IntegrationInfo {
-        name: "egui_glow",
-        web_info: None,
-        prefer_dark_mode: None, // TODO: figure out system default
-        cpu_usage: previous_frame_time,
-        native_pixels_per_point: Some(egui_winit::native_pixels_per_point(window)),
-    }
-}
-
 // ----------------------------------------------------------------------------
 
 pub use epi::NativeOptions;
 
 /// Run an egui app
 #[allow(unsafe_code)]
-pub fn run(mut app: Box<dyn epi::App>, native_options: &epi::NativeOptions) -> ! {
+pub fn run(app: Box<dyn epi::App>, native_options: &epi::NativeOptions) -> ! {
-    let mut persistence = egui_winit::epi::Persistence::from_app_name(app.name());
+    let persistence = egui_winit::epi::Persistence::from_app_name(app.name());
-
     let window_settings = persistence.load_window_settings();
-    let event_loop = glutin::event_loop::EventLoop::with_user_event();
     let window_builder =
         egui_winit::epi::window_builder(native_options, &window_settings).with_title(app.name());
+    let event_loop = glutin::event_loop::EventLoop::with_user_event();
     let (gl_window, gl) = create_display(window_builder, &event_loop);
 
     let repaint_signal = std::sync::Arc::new(GlowRepaintSignal(std::sync::Mutex::new(
         event_loop.create_proxy(),
     )));
 
-    let mut egui = EguiGlow::new(&gl_window, &gl);
+    let mut painter = crate::Painter::new(&gl);
-    *egui.ctx().memory() = persistence.load_memory().unwrap_or_default();
+    let mut integration = egui_winit::epi::EpiIntegration::new(
-
+        "egui_glow",
-    {
+        gl_window.window(),
-        let (ctx, painter) = egui.ctx_and_painter_mut();
+        &mut painter,
-        let mut app_output = epi::backend::AppOutput::default();
+        repaint_signal,
-        let mut frame = epi::backend::FrameBuilder {
+        persistence,
-            info: integration_info(gl_window.window(), None),
+        app,
-            tex_allocator: painter,
+    );
-            output: &mut app_output,
-            repaint_signal: repaint_signal.clone(),
-        }
-        .build();
-        app.setup(ctx, &mut frame, persistence.storage());
-    }
-
-    let mut previous_frame_time = None;
 
     let mut is_focused = true;
 
-    if app.warm_up_enabled() {
-        let saved_memory = egui.ctx().memory().clone();
-        egui.ctx().memory().set_everything_is_visible(true);
-
-        egui.begin_frame(gl_window.window());
-        let (ctx, painter) = egui.ctx_and_painter_mut();
-        let mut app_output = epi::backend::AppOutput::default();
-        let mut frame = epi::backend::FrameBuilder {
-            info: integration_info(gl_window.window(), None),
-            tex_allocator: painter,
-            output: &mut app_output,
-            repaint_signal: repaint_signal.clone(),
-        }
-        .build();
-
-        app.update(ctx, &mut frame);
-
-        let _ = egui.end_frame(gl_window.window());
-
-        *egui.ctx().memory() = saved_memory; // We don't want to remember that windows were huge.
-        egui.ctx().clear_animations();
-
-        // TODO: handle app_output
-        // eprintln!("Warmed up in {} ms", warm_up_start.elapsed().as_millis())
-    }
-
     event_loop.run(move |event, _, control_flow| {
         let mut redraw = || {
             if !is_focused {
@@ -149,44 +100,31 @@ pub fn run(mut app: Box<dyn epi::App>, native_options: &epi::NativeOptions) -> !
                 std::thread::sleep(std::time::Duration::from_millis(10));
             }
 
-            let frame_start = std::time::Instant::now();
+            let (needs_repaint, shapes) = integration.update(gl_window.window(), &mut painter);
-
+            let clipped_meshes = integration.egui_ctx.tessellate(shapes);
-            egui.begin_frame(gl_window.window());
-            let (ctx, painter) = egui.ctx_and_painter_mut();
-            let mut app_output = epi::backend::AppOutput::default();
-            let mut frame = epi::backend::FrameBuilder {
-                info: integration_info(gl_window.window(), previous_frame_time),
-                tex_allocator: painter,
-                output: &mut app_output,
-                repaint_signal: repaint_signal.clone(),
-            }
-            .build();
-            app.update(ctx, &mut frame);
-            let (needs_repaint, shapes) = egui.end_frame(gl_window.window());
-
-            let frame_time = (Instant::now() - frame_start).as_secs_f64() as f32;
-            previous_frame_time = Some(frame_time);
 
             {
-                let color = app.clear_color();
+                let color = integration.app.clear_color();
                 unsafe {
                     use glow::HasContext as _;
                     gl.disable(glow::SCISSOR_TEST);
                     gl.clear_color(color[0], color[1], color[2], color[3]);
                     gl.clear(glow::COLOR_BUFFER_BIT);
                 }
-                egui.paint(&gl_window, &gl, shapes);
+
+                painter.paint_meshes(
+                    &gl_window,
+                    &gl,
+                    integration.egui_ctx.pixels_per_point(),
+                    clipped_meshes,
+                    &integration.egui_ctx.texture(),
+                );
+
                 gl_window.swap_buffers().unwrap();
             }
 
             {
-                egui_winit::epi::handle_app_output(
+                *control_flow = if integration.should_quit() {
-                    gl_window.window(),
-                    egui.ctx().pixels_per_point(),
-                    app_output.clone(),
-                );
-
-                *control_flow = if app_output.quit {
                     glutin::event_loop::ControlFlow::Exit
                 } else if needs_repaint {
                     gl_window.window().request_redraw();
@@ -196,7 +134,7 @@ pub fn run(mut app: Box<dyn epi::App>, native_options: &epi::NativeOptions) -> !
                 };
             }
 
-            persistence.maybe_autosave(&mut *app, egui.ctx(), gl_window.window());
+            integration.maybe_autosave(gl_window.window());
         };
 
         match event {
@@ -207,10 +145,6 @@ pub fn run(mut app: Box<dyn epi::App>, native_options: &epi::NativeOptions) -> !
             glutin::event::Event::RedrawRequested(_) if !cfg!(windows) => redraw(),
 
             glutin::event::Event::WindowEvent { event, .. } => {
-                if egui.is_quit_event(&event) {
-                    *control_flow = glutin::event_loop::ControlFlow::Exit;
-                }
-
                 if let glutin::event::WindowEvent::Focused(new_focused) = event {
                     is_focused = new_focused;
                 }
@@ -219,20 +153,20 @@ pub fn run(mut app: Box<dyn epi::App>, native_options: &epi::NativeOptions) -> !
                     gl_window.resize(physical_size);
                 }
 
-                egui.on_event(&event);
+                integration.on_event(&event);
+                if integration.should_quit() {
+                    *control_flow = glutin::event_loop::ControlFlow::Exit;
+                }
 
                 gl_window.window().request_redraw(); // TODO: ask egui if the events warrants a repaint instead
             }
             glutin::event::Event::LoopDestroyed => {
-                app.on_exit();
+                integration.on_exit(gl_window.window());
-                persistence.save(&mut *app, egui.ctx(), gl_window.window());
+                painter.destroy(&gl);
-                egui.destroy(&gl);
             }
-
             glutin::event::Event::UserEvent(RequestRepaintEvent) => {
                 gl_window.window().request_redraw();
             }
-
             _ => (),
         }
     });

egui_glow/src/lib.rs

@@ -101,9 +101,9 @@ pub use egui_winit;
 
 /// Use [`egui`] from a [`glow`] app.
 pub struct EguiGlow {
-    egui_ctx: egui::CtxRef,
+    pub egui_ctx: egui::CtxRef,
-    egui_winit: egui_winit::State,
+    pub egui_winit: egui_winit::State,
-    painter: crate::Painter,
+    pub painter: crate::Painter,
 }
 
 impl EguiGlow {
@@ -118,26 +118,6 @@ impl EguiGlow {
         }
     }
 
-    pub fn ctx(&self) -> &egui::CtxRef {
-        &self.egui_ctx
-    }
-
-    pub fn painter_mut(&mut self) -> &mut crate::Painter {
-        &mut self.painter
-    }
-
-    pub fn ctx_and_painter_mut(&mut self) -> (&egui::CtxRef, &mut crate::Painter) {
-        (&self.egui_ctx, &mut self.painter)
-    }
-
-    pub fn pixels_per_point(&self) -> f32 {
-        self.egui_winit.pixels_per_point()
-    }
-
-    pub fn egui_input(&self) -> &egui::RawInput {
-        self.egui_winit.egui_input()
-    }
-
     /// Returns `true` if egui wants exclusive use of this event
     /// (e.g. a mouse click on an egui window, or entering text into a text field).
     /// For instance, if you use egui for a game, you want to first call this
@@ -153,34 +133,22 @@ impl EguiGlow {
         self.egui_winit.is_quit_event(event)
     }
 
-    pub fn begin_frame(&mut self, window: &glutin::window::Window) {
-        let raw_input = self.take_raw_input(window);
-        self.begin_frame_with_input(raw_input);
-    }
-
-    pub fn begin_frame_with_input(&mut self, raw_input: egui::RawInput) {
-        self.egui_ctx.begin_frame(raw_input);
-    }
-
-    /// Prepare for a new frame. Normally you would call [`Self::begin_frame`] instead.
-    pub fn take_raw_input(&mut self, window: &glutin::window::Window) -> egui::RawInput {
-        self.egui_winit.take_egui_input(window)
-    }
-
     /// Returns `needs_repaint` and shapes to draw.
-    pub fn end_frame(
+    pub fn run(
         &mut self,
         window: &glutin::window::Window,
+        mut run_ui: impl FnMut(&egui::CtxRef),
     ) -> (bool, Vec<egui::epaint::ClippedShape>) {
+        let raw_input = self.egui_winit.take_egui_input(window);
+        self.egui_ctx.begin_frame(raw_input);
+
+        run_ui(&self.egui_ctx);
+
         let (egui_output, shapes) = self.egui_ctx.end_frame();
         let needs_repaint = egui_output.needs_repaint;
-        self.handle_output(window, egui_output);
-        (needs_repaint, shapes)
-    }
-
-    pub fn handle_output(&mut self, window: &glutin::window::Window, output: egui::Output) {
         self.egui_winit
-            .handle_output(window, &self.egui_ctx, output);
+            .handle_output(window, &self.egui_ctx, egui_output);
+        (needs_repaint, shapes)
     }
 
     pub fn paint(
@@ -199,6 +167,7 @@ impl EguiGlow {
         );
     }
 
+    /// Call to release the allocated graphics resources.
     pub fn destroy(&mut self, gl: &glow::Context) {
         self.painter.destroy(gl);
     }

egui_web/src/backend.rs

@@ -4,72 +4,14 @@ pub use egui::{pos2, Color32};
 
 // ----------------------------------------------------------------------------
 
-pub struct WebBackend {
+fn create_painter(canvas_id: &str) -> Result<Box<dyn Painter>, JsValue> {
-    egui_ctx: egui::CtxRef,
-    painter: Box<dyn Painter>,
-    previous_frame_time: Option<f32>,
-    frame_start: Option<f64>,
-}
-
-impl WebBackend {
-    pub fn new(canvas_id: &str) -> Result<Self, JsValue> {
-        let ctx = egui::CtxRef::default();
-
-        let painter: Box<dyn Painter> =
     if let Ok(webgl2_painter) = webgl2::WebGl2Painter::new(canvas_id) {
         console_log("Using WebGL2 backend");
-                Box::new(webgl2_painter)
+        Ok(Box::new(webgl2_painter))
     } else {
         console_log("Falling back to WebGL1 backend");
-                Box::new(webgl1::WebGlPainter::new(canvas_id)?)
+        let webgl1_painter = webgl1::WebGlPainter::new(canvas_id)?;
-            };
+        Ok(Box::new(webgl1_painter))
-
-        Ok(Self {
-            egui_ctx: ctx,
-            painter,
-            previous_frame_time: None,
-            frame_start: None,
-        })
-    }
-
-    /// id of the canvas html element containing the rendering
-    pub fn canvas_id(&self) -> &str {
-        self.painter.canvas_id()
-    }
-
-    pub fn begin_frame(&mut self, raw_input: egui::RawInput) {
-        self.frame_start = Some(now_sec());
-        self.egui_ctx.begin_frame(raw_input)
-    }
-
-    pub fn end_frame(&mut self) -> Result<(egui::Output, Vec<egui::ClippedMesh>), JsValue> {
-        let frame_start = self
-            .frame_start
-            .take()
-            .expect("unmatched calls to begin_frame/end_frame");
-
-        let (output, shapes) = self.egui_ctx.end_frame();
-        let clipped_meshes = self.egui_ctx.tessellate(shapes);
-
-        let now = now_sec();
-        self.previous_frame_time = Some((now - frame_start) as f32);
-
-        Ok((output, clipped_meshes))
-    }
-
-    pub fn paint(
-        &mut self,
-        clear_color: egui::Rgba,
-        clipped_meshes: Vec<egui::ClippedMesh>,
-    ) -> Result<(), JsValue> {
-        self.painter.upload_egui_texture(&self.egui_ctx.texture());
-        self.painter.clear(clear_color);
-        self.painter
-            .paint_meshes(clipped_meshes, self.egui_ctx.pixels_per_point())
-    }
-
-    pub fn painter_debug_info(&self) -> String {
-        self.painter.debug_info()
     }
 }
 
@@ -129,7 +71,9 @@ impl epi::RepaintSignal for NeedRepaint {
 // ----------------------------------------------------------------------------
 
 pub struct AppRunner {
-    web_backend: WebBackend,
+    egui_ctx: egui::CtxRef,
+    painter: Box<dyn Painter>,
+    previous_frame_time: Option<f32>,
     pub(crate) input: WebInput,
     app: Box<dyn epi::App>,
     pub(crate) needs_repaint: std::sync::Arc<NeedRepaint>,
@@ -142,21 +86,25 @@ pub struct AppRunner {
 }
 
 impl AppRunner {
-    pub fn new(web_backend: WebBackend, app: Box<dyn epi::App>) -> Result<Self, JsValue> {
+    pub fn new(canvas_id: &str, app: Box<dyn epi::App>) -> Result<Self, JsValue> {
-        load_memory(&web_backend.egui_ctx);
+        let egui_ctx = egui::CtxRef::default();
+
+        load_memory(&egui_ctx);
 
         let prefer_dark_mode = crate::prefer_dark_mode();
 
         if prefer_dark_mode == Some(true) {
-            web_backend.egui_ctx.set_visuals(egui::Visuals::dark());
+            egui_ctx.set_visuals(egui::Visuals::dark());
         } else {
-            web_backend.egui_ctx.set_visuals(egui::Visuals::light());
+            egui_ctx.set_visuals(egui::Visuals::light());
         }
 
         let storage = LocalStorage::default();
 
         let mut runner = Self {
-            web_backend,
+            egui_ctx,
+            painter: create_painter(canvas_id)?,
+            previous_frame_time: None,
             input: Default::default(),
             app,
             needs_repaint: Default::default(),
@@ -172,23 +120,21 @@ impl AppRunner {
             let mut app_output = epi::backend::AppOutput::default();
             let mut frame = epi::backend::FrameBuilder {
                 info: runner.integration_info(),
-                tex_allocator: runner.web_backend.painter.as_tex_allocator(),
+                tex_allocator: runner.painter.as_tex_allocator(),
                 output: &mut app_output,
                 repaint_signal: runner.needs_repaint.clone(),
             }
             .build();
-            runner.app.setup(
+            runner
-                &runner.web_backend.egui_ctx,
+                .app
-                &mut frame,
+                .setup(&runner.egui_ctx, &mut frame, Some(&runner.storage));
-                Some(&runner.storage),
-            );
         }
 
         Ok(runner)
     }
 
     pub fn egui_ctx(&self) -> &egui::CtxRef {
-        &self.web_backend.egui_ctx
+        &self.egui_ctx
     }
 
     pub fn auto_save(&mut self) {
@@ -197,7 +143,7 @@ impl AppRunner {
 
         if time_since_last_save > self.app.auto_save_interval().as_secs_f64() {
             if self.app.persist_egui_memory() {
-                save_memory(&self.web_backend.egui_ctx);
+                save_memory(&self.egui_ctx);
             }
             self.app.save(&mut self.storage);
             self.last_save_time = now;
@@ -205,19 +151,16 @@ impl AppRunner {
     }
 
     pub fn canvas_id(&self) -> &str {
-        self.web_backend.canvas_id()
+        self.painter.canvas_id()
     }
 
     pub fn warm_up(&mut self) -> Result<(), JsValue> {
         if self.app.warm_up_enabled() {
-            let saved_memory = self.web_backend.egui_ctx.memory().clone();
+            let saved_memory = self.egui_ctx.memory().clone();
-            self.web_backend
+            self.egui_ctx.memory().set_everything_is_visible(true);
-                .egui_ctx
-                .memory()
-                .set_everything_is_visible(true);
             self.logic()?;
-            *self.web_backend.egui_ctx.memory() = saved_memory; // We don't want to remember that windows were huge.
+            *self.egui_ctx.memory() = saved_memory; // We don't want to remember that windows were huge.
-            self.web_backend.egui_ctx.clear_animations();
+            self.egui_ctx.clear_animations();
         }
         Ok(())
     }
@@ -229,59 +172,98 @@ impl AppRunner {
                 web_location_hash: location_hash().unwrap_or_default(),
             }),
             prefer_dark_mode: self.prefer_dark_mode,
-            cpu_usage: self.web_backend.previous_frame_time,
+            cpu_usage: self.previous_frame_time,
             native_pixels_per_point: Some(native_pixels_per_point()),
         }
     }
 
     pub fn logic(&mut self) -> Result<(egui::Output, Vec<egui::ClippedMesh>), JsValue> {
-        resize_canvas_to_screen_size(self.web_backend.canvas_id(), self.app.max_size_points());
+        let frame_start = now_sec();
-        let canvas_size = canvas_size_in_points(self.web_backend.canvas_id());
+
+        resize_canvas_to_screen_size(self.canvas_id(), self.app.max_size_points());
+        let canvas_size = canvas_size_in_points(self.canvas_id());
         let raw_input = self.input.new_frame(canvas_size);
 
-        self.web_backend.begin_frame(raw_input);
+        self.egui_ctx.begin_frame(raw_input);
 
         let mut app_output = epi::backend::AppOutput::default();
         let mut frame = epi::backend::FrameBuilder {
             info: self.integration_info(),
-            tex_allocator: self.web_backend.painter.as_tex_allocator(),
+            tex_allocator: self.painter.as_tex_allocator(),
             output: &mut app_output,
             repaint_signal: self.needs_repaint.clone(),
         }
         .build();
 
-        self.app.update(&self.web_backend.egui_ctx, &mut frame);
+        self.app.update(&self.egui_ctx, &mut frame);
-        let (egui_output, clipped_meshes) = self.web_backend.end_frame()?;
 
-        if self.web_backend.egui_ctx.memory().options.screen_reader {
+        let (egui_output, shapes) = self.egui_ctx.end_frame();
-            self.screen_reader.speak(&egui_output.events_description());
+        let clipped_meshes = self.egui_ctx.tessellate(shapes);
-        }
+
-        handle_output(&egui_output, self);
+        self.handle_egui_output(&egui_output);
 
         {
             let epi::backend::AppOutput {
                 quit: _,         // Can't quit a web page
                 window_size: _,  // Can't resize a web page
-                window_title: _,
+                window_title: _, // TODO: change title of window
-                decorated: _,   // Can't show decorations
+                decorated: _,    // Can't toggle decorations
                 drag_window: _,  // Can't be dragged
             } = app_output;
         }
 
+        self.previous_frame_time = Some((now_sec() - frame_start) as f32);
         Ok((egui_output, clipped_meshes))
     }
 
     pub fn paint(&mut self, clipped_meshes: Vec<egui::ClippedMesh>) -> Result<(), JsValue> {
-        self.web_backend
+        self.painter.upload_egui_texture(&self.egui_ctx.texture());
-            .paint(self.app.clear_color(), clipped_meshes)
+        self.painter.clear(self.app.clear_color());
+        self.painter
+            .paint_meshes(clipped_meshes, self.egui_ctx.pixels_per_point())
+    }
+
+    fn handle_egui_output(&mut self, output: &egui::Output) {
+        if self.egui_ctx.memory().options.screen_reader {
+            self.screen_reader.speak(&output.events_description());
+        }
+
+        let egui::Output {
+            cursor_icon,
+            open_url,
+            copied_text,
+            needs_repaint: _, // handled elsewhere
+            events: _,        // already handled
+            mutable_text_under_cursor,
+            text_cursor_pos,
+        } = output;
+
+        set_cursor_icon(*cursor_icon);
+        if let Some(open) = open_url {
+            crate::open_url(&open.url, open.new_tab);
+        }
+
+        #[cfg(web_sys_unstable_apis)]
+        if !copied_text.is_empty() {
+            set_clipboard_text(copied_text);
+        }
+
+        #[cfg(not(web_sys_unstable_apis))]
+        let _ = copied_text;
+
+        self.mutable_text_under_cursor = *mutable_text_under_cursor;
+
+        if &self.text_cursor_pos != text_cursor_pos {
+            move_text_cursor(text_cursor_pos, self.canvas_id());
+            self.text_cursor_pos = *text_cursor_pos;
+        }
     }
 }
 
 /// Install event listeners to register different input events
 /// and start running the given app.
 pub fn start(canvas_id: &str, app: Box<dyn epi::App>) -> Result<AppRunnerRef, JsValue> {
-    let backend = WebBackend::new(canvas_id)?;
+    let mut runner = AppRunner::new(canvas_id, app)?;
-    let mut runner = AppRunner::new(backend, app)?;
     runner.warm_up()?;
     start_runner(runner)
 }

egui_web/src/lib.rs

@@ -293,38 +293,6 @@ impl epi::Storage for LocalStorage {
 
 // ----------------------------------------------------------------------------
 
-pub fn handle_output(output: &egui::Output, runner: &mut AppRunner) {
-    let egui::Output {
-        cursor_icon,
-        open_url,
-        copied_text,
-        needs_repaint: _, // handled elsewhere
-        events: _,        // we ignore these (TODO: accessibility screen reader)
-        mutable_text_under_cursor,
-        text_cursor_pos,
-    } = output;
-
-    set_cursor_icon(*cursor_icon);
-    if let Some(open) = open_url {
-        crate::open_url(&open.url, open.new_tab);
-    }
-
-    #[cfg(web_sys_unstable_apis)]
-    if !copied_text.is_empty() {
-        set_clipboard_text(copied_text);
-    }
-
-    #[cfg(not(web_sys_unstable_apis))]
-    let _ = copied_text;
-
-    runner.mutable_text_under_cursor = *mutable_text_under_cursor;
-
-    if &runner.text_cursor_pos != text_cursor_pos {
-        move_text_cursor(text_cursor_pos, runner.canvas_id());
-        runner.text_cursor_pos = *text_cursor_pos;
-    }
-}
-
 pub fn set_cursor_icon(cursor: egui::CursorIcon) -> Option<()> {
     let document = web_sys::window()?.document()?;
     document