Pass out pixels_per_point in output for use in tesselation

crates/eframe/src/native/run.rs

@@ -562,6 +562,7 @@ mod glow_integration {
                 platform_output,
                 textures_delta,
                 shapes,
+                pixels_per_point,
                 viewports: viewports_out,
                 viewport_commands,
             } = full_output;
@@ -580,10 +581,6 @@ mod glow_integration {
             integration.post_update(app.as_mut(), window);
             integration.handle_platform_output(window, viewport_id, platform_output, egui_winit);
 
-            let pixels_per_point = integration
-                .egui_ctx
-                .input_for(viewport_id, |i| i.pixels_per_point());
-
             let clipped_primitives = integration.egui_ctx.tessellate(shapes, pixels_per_point);
 
             *current_gl_context = Some(
@@ -1581,7 +1578,7 @@ mod glow_integration {
         let screen_size_in_pixels: [u32; 2] = window.inner_size().into();
 
         let pixels_per_point = egui_ctx.input_for(ids.this, |i| i.pixels_per_point());
-        let clipped_primitives = egui_ctx.tessellate(output.shapes, pixels_per_point);
+        let clipped_primitives = egui_ctx.tessellate(output.shapes, output.pixels_per_point);
 
         let mut painter = painter.borrow_mut();
 
@@ -2181,7 +2178,7 @@ mod wgpu_integration {
         }
 
         let pixels_per_point = egui_ctx.input_for(ids.this, |i| i.pixels_per_point());
-        let clipped_primitives = egui_ctx.tessellate(output.shapes, pixels_per_point);
+        let clipped_primitives = egui_ctx.tessellate(output.shapes, output.pixels_per_point);
         painter.paint_and_update_textures(
             ids.this,
             pixels_per_point,
@@ -2504,6 +2501,7 @@ mod wgpu_integration {
                 platform_output,
                 textures_delta,
                 shapes,
+                pixels_per_point,
                 viewports: out_viewports,
                 viewport_commands,
             } = full_output;
@@ -2511,10 +2509,6 @@ mod wgpu_integration {
             integration.handle_platform_output(window, viewport_id, platform_output, egui_winit);
 
             {
-                let pixels_per_point = integration
-                    .egui_ctx
-                    .input_for(viewport_id, |i| i.pixels_per_point());
-
                 let clipped_primitives = integration.egui_ctx.tessellate(shapes, pixels_per_point);
 
                 let screenshot_requested = &mut integration.frame.output.screenshot_requested;

crates/egui/src/context.rs

@@ -429,7 +429,7 @@ impl ContextImpl {
 ///         });
 ///     });
 ///     handle_platform_output(full_output.platform_output);
-///     let clipped_primitives = ctx.tessellate(full_output.shapes); // create triangles to paint
+///     let clipped_primitives = ctx.tessellate(full_output.shapes, full_output.pixels_per_point);
 ///     paint(full_output.textures_delta, clipped_primitives);
 /// }
 /// ```
@@ -1486,6 +1486,7 @@ impl ContextImpl {
     fn end_frame(&mut self) -> FullOutput {
         let ended_viewport_id = self.viewport_id();
         let viewport = self.viewports.entry(ended_viewport_id).or_default();
+        let pixels_per_point = viewport.input.pixels_per_point;
 
         if viewport.input.wants_repaint() {
             self.repaint.requested_repaint(&ended_viewport_id);
@@ -1607,6 +1608,7 @@ impl ContextImpl {
             platform_output,
             textures_delta,
             shapes,
+            pixels_per_point,
             viewports: out_viewports,
             // We should not process viewport commands when we are a sync viewport, because that will cause a deadlock for egui backend
             viewport_commands: if is_last {

crates/egui/src/data/output.rs

@@ -21,6 +21,11 @@ pub struct FullOutput {
     /// You can use [`crate::Context::tessellate`] to turn this into triangles.
     pub shapes: Vec<epaint::ClippedShape>,
 
+    /// The number of physical pixels per logical ui point, for the viewport that was updated.
+    ///
+    /// You can pass this to [`Context::tesselate`] together with [`Self::shapes`].
+    pub pixels_per_point: f32,
+
     /// All the active viewports, excluding the root.
     pub viewports: Vec<ViewportOutput>,
 
@@ -35,6 +40,7 @@ impl FullOutput {
             platform_output,
             textures_delta,
             shapes,
+            pixels_per_point,
             mut viewports,
             mut viewport_commands,
         } = newer;
@@ -42,6 +48,7 @@ impl FullOutput {
         self.platform_output.append(platform_output);
         self.textures_delta.append(textures_delta);
         self.shapes = shapes; // Only paint the latest
+        self.pixels_per_point = pixels_per_point; // Use latest
         self.viewports.append(&mut viewports);
         self.viewport_commands.append(&mut viewport_commands);
     }

crates/egui/src/lib.rs

@@ -134,7 +134,7 @@
 //!         });
 //!     });
 //!     handle_platform_output(full_output.platform_output);
-//!     let clipped_primitives = ctx.tessellate(full_output.shapes); // create triangles to paint
+//!     let clipped_primitives = ctx.tessellate(full_output.shapes, full_output.pixels_per_point);
 //!     paint(full_output.textures_delta, clipped_primitives);
 //! }
 //! ```

crates/egui_demo_lib/benches/benchmark.rs

@@ -9,7 +9,6 @@ pub fn criterion_benchmark(c: &mut Criterion) {
     {
         let ctx = egui::Context::default();
         let mut demo_windows = egui_demo_lib::DemoWindows::default();
-        let pixels_per_point = 1.0;
 
         // The most end-to-end benchmark.
         c.bench_function("demo_with_tessellate__realistic", |b| {
@@ -17,7 +16,7 @@ pub fn criterion_benchmark(c: &mut Criterion) {
                 let full_output = ctx.run(RawInput::default(), |ctx| {
                     demo_windows.ui(ctx);
                 });
-                ctx.tessellate(full_output.shapes, pixels_per_point)
+                ctx.tessellate(full_output.shapes, full_output.pixels_per_point)
             });
         });
 
@@ -33,7 +32,7 @@ pub fn criterion_benchmark(c: &mut Criterion) {
             demo_windows.ui(ctx);
         });
         c.bench_function("demo_only_tessellate", |b| {
-            b.iter(|| ctx.tessellate(full_output.shapes.clone(), pixels_per_point));
+            b.iter(|| ctx.tessellate(full_output.shapes.clone(), full_output.pixels_per_point));
         });
     }
 

crates/egui_demo_lib/src/lib.rs

@@ -71,14 +71,13 @@ fn test_egui_e2e() {
     let mut demo_windows = crate::DemoWindows::default();
     let ctx = egui::Context::default();
     let raw_input = egui::RawInput::default();
-    let pixels_per_point = 1.0;
 
     const NUM_FRAMES: usize = 5;
     for _ in 0..NUM_FRAMES {
         let full_output = ctx.run(raw_input.clone(), |ctx| {
             demo_windows.ui(ctx);
         });
-        let clipped_primitives = ctx.tessellate(full_output.shapes, pixels_per_point);
+        let clipped_primitives = ctx.tessellate(full_output.shapes, full_output.pixels_per_point);
         assert!(!clipped_primitives.is_empty());
     }
 }
@@ -91,14 +90,13 @@ fn test_egui_zero_window_size() {
         screen_rect: Some(egui::Rect::from_min_max(egui::Pos2::ZERO, egui::Pos2::ZERO)),
         ..Default::default()
     };
-    let pixels_per_point = 1.0;
 
     const NUM_FRAMES: usize = 5;
     for _ in 0..NUM_FRAMES {
         let full_output = ctx.run(raw_input.clone(), |ctx| {
             demo_windows.ui(ctx);
         });
-        let clipped_primitives = ctx.tessellate(full_output.shapes, pixels_per_point);
+        let clipped_primitives = ctx.tessellate(full_output.shapes, full_output.pixels_per_point);
         assert!(
             clipped_primitives.is_empty(),
             "There should be nothing to show, has at least one primitive with clip_rect: {:?}",

crates/egui_glow/src/winit.rs

@@ -10,7 +10,9 @@ pub struct EguiGlow {
     pub egui_winit: egui_winit::State,
     pub painter: crate::Painter,
 
+    // output from the last update:
     shapes: Vec<egui::epaint::ClippedShape>,
+    pixels_per_point: f32,
     textures_delta: egui::TexturesDelta,
 }
 
@@ -28,15 +30,19 @@ impl EguiGlow {
             })
             .unwrap();
 
+        let egui_winit = egui_winit::State::new(
+            event_loop,
+            native_pixels_per_point,
+            Some(painter.max_texture_side()),
+        );
+        let pixels_per_point = egui_winit.pixels_per_point();
+
         Self {
             egui_ctx: Default::default(),
-            egui_winit: egui_winit::State::new(
+            egui_winit,
-                event_loop,
-                native_pixels_per_point,
-                Some(painter.max_texture_side()),
-            ),
             painter,
             shapes: Default::default(),
+            pixels_per_point,
             textures_delta: Default::default(),
         }
     }
@@ -55,6 +61,7 @@ impl EguiGlow {
             platform_output,
             textures_delta,
             shapes,
+            pixels_per_point,
             viewports,
             viewport_commands,
         } = self.egui_ctx.run(raw_input, run_ui);
@@ -76,6 +83,7 @@ impl EguiGlow {
         );
 
         self.shapes = shapes;
+        self.pixels_per_point = pixels_per_point;
         self.textures_delta.append(textures_delta);
     }
 
@@ -88,7 +96,7 @@ impl EguiGlow {
             self.painter.set_texture(id, &image_delta);
         }
 
-        let pixels_per_point = self.egui_ctx.pixels_per_point();
+        let pixels_per_point = self.pixels_per_point;
         let clipped_primitives = self.egui_ctx.tessellate(shapes, pixels_per_point);
         let dimensions: [u32; 2] = window.inner_size().into();
         self.painter