Partial font texture update

CHANGELOG.md

@@ -20,7 +20,9 @@ NOTE: [`epaint`](epaint/CHANGELOG.md), [`eframe`](eframe/CHANGELOG.md), [`egui_w
 * `Context` can now be cloned and stored between frames ([#1050](https://github.com/emilk/egui/pull/1050)).
 * Renamed `Ui::visible` to `Ui::is_visible`.
 * Split `Event::Text` into `Event::Text` and `Event::Paste` ([#1058](https://github.com/emilk/egui/pull/1058)).
-* For integrations: `FontImage` has been replaced by `TexturesDelta` (found in `Output`), describing what textures were loaded and freed each frame ([#1110](https://github.com/emilk/egui/pull/1110)).
+* For integrations:
+  * `FontImage` has been replaced by `TexturesDelta` (found in `Output`), describing what textures were loaded and freed each frame ([#1110](https://github.com/emilk/egui/pull/1110)).
+  * The painter must support partial texture updates ([#1149](https://github.com/emilk/egui/pull/1149)).
 
 ### Fixed 🐛
 * Context menu now respects the theme ([#1043](https://github.com/emilk/egui/pull/1043))

egui/src/context.rs

@@ -33,7 +33,6 @@ struct ContextImpl {
     fonts: Option<Fonts>,
     memory: Memory,
     animation_manager: AnimationManager,
-    latest_font_image_version: Option<u64>,
     tex_manager: WrappedTextureManager,
 
     input: InputState,
@@ -709,17 +708,15 @@ impl Context {
                 .memory
                 .end_frame(&ctx_impl.input, &ctx_impl.frame_state.used_ids);
 
-            let font_image = ctx_impl.fonts.as_ref().unwrap().font_image();
-            let font_image_version = font_image.version;
-
-            if Some(font_image_version) != ctx_impl.latest_font_image_version {
+            let font_image_delta = ctx_impl.fonts.as_ref().unwrap().font_image_delta();
+            if let Some(font_image_delta) = font_image_delta {
                 ctx_impl
                     .tex_manager
                     .0
                     .write()
-                    .set(TextureId::default(), font_image.image.clone().into());
-                ctx_impl.latest_font_image_version = Some(font_image_version);
+                    .set(TextureId::default(), font_image_delta);
             }
+
             ctx_impl
                 .output
                 .textures_delta
@@ -757,7 +754,7 @@ impl Context {
         let clipped_meshes = tessellator::tessellate_shapes(
             shapes,
             tessellation_options,
-            self.fonts().font_image().size(),
+            self.fonts().font_image_size(),
         );
         self.write().paint_stats = paint_stats.with_clipped_meshes(&clipped_meshes);
         clipped_meshes
@@ -961,8 +958,8 @@ impl Context {
             .show(ui, |ui| {
                 let mut font_definitions = self.fonts().definitions().clone();
                 font_definitions.ui(ui);
-                let font_image = self.fonts().font_image();
-                font_image.ui(ui);
+                let font_image_size = self.fonts().font_image_size();
+                crate::introspection::font_texture_ui(ui, font_image_size);
                 self.set_fonts(font_definitions);
             });
 

egui/src/introspection.rs

@@ -1,60 +1,58 @@
 //! uis for egui types.
 use crate::*;
 
-impl Widget for &epaint::FontImage {
-    fn ui(self, ui: &mut Ui) -> Response {
-        use epaint::Mesh;
-
-        ui.vertical(|ui| {
-            // Show font texture in demo Ui
-            let [width, height] = self.size();
-
-            ui.label(format!(
-                "Texture size: {} x {} (hover to zoom)",
-                width, height
-            ));
-            if width <= 1 || height <= 1 {
-                return;
-            }
-            let mut size = vec2(width as f32, height as f32);
-            if size.x > ui.available_width() {
-                size *= ui.available_width() / size.x;
-            }
-            let (rect, response) = ui.allocate_at_least(size, Sense::hover());
-            let mut mesh = Mesh::default();
-            mesh.add_rect_with_uv(
-                rect,
-                [pos2(0.0, 0.0), pos2(1.0, 1.0)].into(),
-                Color32::WHITE,
-            );
-            ui.painter().add(Shape::mesh(mesh));
-
-            let (tex_w, tex_h) = (width as f32, height as f32);
-
-            response
-                .on_hover_cursor(CursorIcon::ZoomIn)
-                .on_hover_ui_at_pointer(|ui| {
-                    if let Some(pos) = ui.ctx().latest_pointer_pos() {
-                        let (_id, zoom_rect) = ui.allocate_space(vec2(128.0, 128.0));
-                        let u = remap_clamp(pos.x, rect.x_range(), 0.0..=tex_w);
-                        let v = remap_clamp(pos.y, rect.y_range(), 0.0..=tex_h);
-
-                        let texel_radius = 32.0;
-                        let u = u.at_least(texel_radius).at_most(tex_w - texel_radius);
-                        let v = v.at_least(texel_radius).at_most(tex_h - texel_radius);
-
-                        let uv_rect = Rect::from_min_max(
-                            pos2((u - texel_radius) / tex_w, (v - texel_radius) / tex_h),
-                            pos2((u + texel_radius) / tex_w, (v + texel_radius) / tex_h),
-                        );
-                        let mut mesh = Mesh::default();
-                        mesh.add_rect_with_uv(zoom_rect, uv_rect, Color32::WHITE);
-                        ui.painter().add(Shape::mesh(mesh));
-                    }
-                });
-        })
-        .response
-    }
+// Show font texture in demo Ui
+pub(crate) fn font_texture_ui(ui: &mut Ui, [width, height]: [usize; 2]) -> Response {
+    use epaint::Mesh;
+
+    ui.vertical(|ui| {
+        let color = if ui.visuals().dark_mode {
+            Color32::WHITE
+        } else {
+            Color32::BLACK
+        };
+
+        ui.label(format!(
+            "Texture size: {} x {} (hover to zoom)",
+            width, height
+        ));
+        if width <= 1 || height <= 1 {
+            return;
+        }
+        let mut size = vec2(width as f32, height as f32);
+        if size.x > ui.available_width() {
+            size *= ui.available_width() / size.x;
+        }
+        let (rect, response) = ui.allocate_at_least(size, Sense::hover());
+        let mut mesh = Mesh::default();
+        mesh.add_rect_with_uv(rect, [pos2(0.0, 0.0), pos2(1.0, 1.0)].into(), color);
+        ui.painter().add(Shape::mesh(mesh));
+
+        let (tex_w, tex_h) = (width as f32, height as f32);
+
+        response
+            .on_hover_cursor(CursorIcon::ZoomIn)
+            .on_hover_ui_at_pointer(|ui| {
+                if let Some(pos) = ui.ctx().latest_pointer_pos() {
+                    let (_id, zoom_rect) = ui.allocate_space(vec2(128.0, 128.0));
+                    let u = remap_clamp(pos.x, rect.x_range(), 0.0..=tex_w);
+                    let v = remap_clamp(pos.y, rect.y_range(), 0.0..=tex_h);
+
+                    let texel_radius = 32.0;
+                    let u = u.at_least(texel_radius).at_most(tex_w - texel_radius);
+                    let v = v.at_least(texel_radius).at_most(tex_h - texel_radius);
+
+                    let uv_rect = Rect::from_min_max(
+                        pos2((u - texel_radius) / tex_w, (v - texel_radius) / tex_h),
+                        pos2((u + texel_radius) / tex_w, (v + texel_radius) / tex_h),
+                    );
+                    let mut mesh = Mesh::default();
+                    mesh.add_rect_with_uv(zoom_rect, uv_rect, color);
+                    ui.painter().add(Shape::mesh(mesh));
+                }
+            });
+    })
+    .response
 }
 
 impl Widget for &mut epaint::text::FontDefinitions {

egui/src/widgets/plot/items/mod.rs

@@ -1087,9 +1087,13 @@ pub struct PlotImage {
 
 impl PlotImage {
     /// Create a new image with position and size in plot coordinates.
-    pub fn new(texture_id: impl Into<TextureId>, position: Value, size: impl Into<Vec2>) -> Self {
+    pub fn new(
+        texture_id: impl Into<TextureId>,
+        center_position: Value,
+        size: impl Into<Vec2>,
+    ) -> Self {
         Self {
-            position,
+            position: center_position,
             name: Default::default(),
             highlight: false,
             texture_id: texture_id.into(),

egui_demo_lib/benches/benchmark.rs

@@ -114,11 +114,7 @@ pub fn criterion_benchmark(c: &mut Criterion) {
         let text_shape = TextShape::new(egui::Pos2::ZERO, galley);
         c.bench_function("tessellate_text", |b| {
             b.iter(|| {
-                tessellator.tessellate_text(
-                    fonts.font_image().size(),
-                    text_shape.clone(),
-                    &mut mesh,
-                );
+                tessellator.tessellate_text(fonts.font_image_size(), text_shape.clone(), &mut mesh);
                 mesh.clear();
             })
         });

egui_demo_lib/src/apps/demo/plot_demo.rs

@@ -343,10 +343,7 @@ impl Widget for &mut ItemsDemo {
         let image = PlotImage::new(
             texture,
             Value::new(0.0, 10.0),
-            [
-                ui.fonts().font_image().width() as f32 / 100.0,
-                ui.fonts().font_image().height() as f32 / 100.0,
-            ],
+            5.0 * vec2(texture.aspect_ratio(), 1.0),
         );
 
         let plot = Plot::new("items_demo")

egui_glium/src/epi_backend.rs

@@ -70,8 +70,8 @@ pub fn run(app: Box<dyn epi::App>, native_options: &epi::NativeOptions) -> ! {
                 integration.update(display.gl_window().window());
             let clipped_meshes = integration.egui_ctx.tessellate(shapes);
 
-            for (id, image) in textures_delta.set {
-                painter.set_texture(&display, id, &image);
+            for (id, image_delta) in textures_delta.set {
+                painter.set_texture(&display, id, &image_delta);
             }
 
             // paint:

egui_glium/src/lib.rs

@@ -155,8 +155,8 @@ impl EguiGlium {
         let shapes = std::mem::take(&mut self.shapes);
         let mut textures_delta = std::mem::take(&mut self.textures_delta);
 
-        for (id, image) in textures_delta.set {
-            self.painter.set_texture(display, id, &image);
+        for (id, image_delta) in textures_delta.set {
+            self.painter.set_texture(display, id, &image_delta);
         }
 
         let clipped_meshes = self.egui_ctx.tessellate(shapes);

egui_glium/src/painter.rs

@@ -185,9 +185,9 @@ impl Painter {
         &mut self,
         facade: &dyn glium::backend::Facade,
         tex_id: egui::TextureId,
-        image: &egui::ImageData,
+        delta: &egui::epaint::ImageDelta,
     ) {
-        let pixels: Vec<(u8, u8, u8, u8)> = match image {
+        let pixels: Vec<(u8, u8, u8, u8)> = match &delta.image {
             egui::ImageData::Color(image) => {
                 assert_eq!(
                     image.width() * image.height(),
@@ -206,15 +206,29 @@ impl Painter {
         };
         let glium_image = glium::texture::RawImage2d {
             data: std::borrow::Cow::Owned(pixels),
-            width: image.width() as _,
-            height: image.height() as _,
+            width: delta.image.width() as _,
+            height: delta.image.height() as _,
             format: glium::texture::ClientFormat::U8U8U8U8,
         };
         let format = texture::SrgbFormat::U8U8U8U8;
         let mipmaps = texture::MipmapsOption::NoMipmap;
-        let gl_texture = SrgbTexture2d::with_format(facade, glium_image, format, mipmaps).unwrap();
 
-        self.textures.insert(tex_id, gl_texture.into());
+        if let Some(pos) = delta.pos {
+            // update a sub-region
+            if let Some(gl_texture) = self.textures.get(&tex_id) {
+                let rect = glium::Rect {
+                    left: pos[0] as _,
+                    bottom: pos[1] as _,
+                    width: glium_image.width,
+                    height: glium_image.height,
+                };
+                gl_texture.main_level().write(rect, glium_image);
+            }
+        } else {
+            let gl_texture =
+                SrgbTexture2d::with_format(facade, glium_image, format, mipmaps).unwrap();
+            self.textures.insert(tex_id, gl_texture.into());
+        }
     }
 
     pub fn free_texture(&mut self, tex_id: egui::TextureId) {

egui_glow/src/epi_backend.rs

@@ -86,8 +86,8 @@ pub fn run(app: Box<dyn epi::App>, native_options: &epi::NativeOptions) -> ! {
                 integration.update(gl_window.window());
             let clipped_meshes = integration.egui_ctx.tessellate(shapes);
 
-            for (id, image) in textures_delta.set {
-                painter.set_texture(&gl, id, &image);
+            for (id, image_delta) in textures_delta.set {
+                painter.set_texture(&gl, id, &image_delta);
             }
 
             // paint:

egui_glow/src/lib.rs

@@ -175,8 +175,8 @@ impl EguiGlow {
         let shapes = std::mem::take(&mut self.shapes);
         let mut textures_delta = std::mem::take(&mut self.textures_delta);
 
-        for (id, image) in textures_delta.set {
-            self.painter.set_texture(gl, id, &image);
+        for (id, image_delta) in textures_delta.set {
+            self.painter.set_texture(gl, id, &image_delta);
         }
 
         let clipped_meshes = self.egui_ctx.tessellate(shapes);