Partial font texture update (#1149)

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;
+// 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| {
-            // Show font texture in demo Ui
-            let [width, height] = self.size();
+    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(),
-                Color32::WHITE,
-            );
-            ui.painter().add(Shape::mesh(mesh));
+        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);
+        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);
+        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 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
-    }
+                    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(),