Reuse last buffer in `Frame` if `mesh_style` matches

3 files changed, 51 insertions, 37 deletions

diff --git a/graphics/src/layer/mesh.rs b/graphics/src/layer/mesh.rs
index 0946317e..a2232a1f 100644
--- a/graphics/src/layer/mesh.rs
+++ b/graphics/src/layer/mesh.rs
@@ -1,7 +1,7 @@
 //! A collection of triangle primitives.
 
-use crate::{Color, Point, Rectangle, triangle};
 use crate::gradient::Gradient;
+use crate::{triangle, Color, Point, Rectangle};
 
 /// A mesh of triangles.
 #[derive(Debug, Clone, Copy)]
@@ -19,16 +19,16 @@ pub struct Mesh<'a> {
     pub style: &'a Style,
 }
 
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, PartialEq)]
 /// Supported shaders for primitives.
 pub enum Style {
     /// Fill a primitive with a solid color.
     Solid(Color),
     /// Fill a primitive with an interpolated color.
-    Gradient(Gradient)
+    Gradient(Gradient),
 }
 
-impl <'a> Into<Style> for Gradient {
+impl<'a> Into<Style> for Gradient {
     fn into(self) -> Style {
         match self {
             Gradient::Linear(linear) => {
diff --git a/graphics/src/widget/canvas/fill.rs b/graphics/src/widget/canvas/fill.rs
index 34cc5e50..9582bf27 100644
--- a/graphics/src/widget/canvas/fill.rs
+++ b/graphics/src/widget/canvas/fill.rs
@@ -2,8 +2,8 @@
 
 use crate::gradient::Gradient;
 use crate::layer::mesh;
-use iced_native::Color;
 use crate::widget::canvas::frame::Transform;
+use iced_native::Color;
 
 /// The style used to fill geometry.
 #[derive(Debug, Clone)]
@@ -64,9 +64,7 @@ impl<'a> Style<'a> {
     /// Converts a fill's [Style] to a [mesh::Style] for use in the renderer's shader.
     pub(crate) fn as_mesh_style(&self, transform: &Transform) -> mesh::Style {
         match self {
-            Style::Solid(color) => {
-                mesh::Style::Solid(*color)
-            },
+            Style::Solid(color) => mesh::Style::Solid(*color),
             Style::Gradient(gradient) => mesh::Style::Gradient(
                 transform.transform_gradient((*gradient).clone()),
             ),
diff --git a/graphics/src/widget/canvas/frame.rs b/graphics/src/widget/canvas/frame.rs
index 3ba72179..677d7bc5 100644
--- a/graphics/src/widget/canvas/frame.rs
+++ b/graphics/src/widget/canvas/frame.rs
@@ -18,13 +18,41 @@ use lyon::tessellation;
 #[allow(missing_debug_implementations)]
 pub struct Frame {
     size: Size,
-    buffers: Vec<(tessellation::VertexBuffers<Vertex2D, u32>, mesh::Style)>,
+    buffers: BufferStack,
     primitives: Vec<Primitive>,
     transforms: Transforms,
     fill_tessellator: tessellation::FillTessellator,
     stroke_tessellator: tessellation::StrokeTessellator,
 }
 
+struct BufferStack {
+    stack: Vec<(tessellation::VertexBuffers<Vertex2D, u32>, mesh::Style)>,
+}
+
+impl BufferStack {
+    fn new() -> Self {
+        Self { stack: Vec::new() }
+    }
+
+    fn get(
+        &mut self,
+        mesh_style: mesh::Style,
+    ) -> tessellation::BuffersBuilder<'_, Vertex2D, u32, Vertex2DBuilder> {
+        match self.stack.last_mut() {
+            Some((_, current_style)) if current_style == &mesh_style => {}
+            _ => {
+                self.stack
+                    .push((tessellation::VertexBuffers::new(), mesh_style));
+            }
+        };
+
+        tessellation::BuffersBuilder::new(
+            &mut self.stack.last_mut().unwrap().0,
+            Vertex2DBuilder,
+        )
+    }
+}
+
 #[derive(Debug)]
 struct Transforms {
     previous: Vec<Transform>,
@@ -67,7 +95,7 @@ impl Frame {
     pub fn new(size: Size) -> Frame {
         Frame {
             size,
-            buffers: Vec::new(),
+            buffers: BufferStack::new(),
             primitives: Vec::new(),
             transforms: Transforms {
                 previous: Vec::new(),
@@ -110,10 +138,9 @@ impl Frame {
     pub fn fill<'a>(&mut self, path: &Path, fill: impl Into<Fill<'a>>) {
         let Fill { style, rule } = fill.into();
 
-        let mut buf = tessellation::VertexBuffers::new();
-
-        let mut buffers =
-            tessellation::BuffersBuilder::new(&mut buf, Vertex2DBuilder);
+        let mut buffer = self
+            .buffers
+            .get(style.as_mesh_style(&self.transforms.current));
 
         let options =
             tessellation::FillOptions::default().with_fill_rule(rule.into());
@@ -122,7 +149,7 @@ impl Frame {
             self.fill_tessellator.tessellate_path(
                 path.raw(),
                 &options,
-                &mut buffers,
+                &mut buffer,
             )
         } else {
             let path = path.transformed(&self.transforms.current.raw);
@@ -130,13 +157,10 @@ impl Frame {
             self.fill_tessellator.tessellate_path(
                 path.raw(),
                 &options,
-                &mut buffers,
+                &mut buffer,
             )
         }
         .expect("Tessellate path.");
-
-        self.buffers
-            .push((buf, style.as_mesh_style(&self.transforms.current)));
     }
 
     /// Draws an axis-aligned rectangle given its top-left corner coordinate and
@@ -149,10 +173,9 @@ impl Frame {
     ) {
         let Fill { style, rule } = fill.into();
 
-        let mut buf = tessellation::VertexBuffers::new();
-
-        let mut buffers =
-            tessellation::BuffersBuilder::new(&mut buf, Vertex2DBuilder);
+        let mut buffer = self
+            .buffers
+            .get(style.as_mesh_style(&self.transforms.current));
 
         let top_left =
             self.transforms.current.raw.transform_point(
@@ -171,12 +194,9 @@ impl Frame {
             .tessellate_rectangle(
                 &lyon::math::Box2D::new(top_left, top_left + size),
                 &options,
-                &mut buffers,
+                &mut buffer,
             )
             .expect("Fill rectangle");
-
-        self.buffers
-            .push((buf, style.as_mesh_style(&self.transforms.current)));
     }
 
     /// Draws the stroke of the given [`Path`] on the [`Frame`] with the
@@ -184,10 +204,9 @@ impl Frame {
     pub fn stroke<'a>(&mut self, path: &Path, stroke: impl Into<Stroke<'a>>) {
         let stroke = stroke.into();
 
-        let mut buf = tessellation::VertexBuffers::new();
-
-        let mut buffers =
-            tessellation::BuffersBuilder::new(&mut buf, Vertex2DBuilder);
+        let mut buffer = self
+            .buffers
+            .get(stroke.style.as_mesh_style(&self.transforms.current));
 
         let mut options = tessellation::StrokeOptions::default();
         options.line_width = stroke.width;
@@ -205,7 +224,7 @@ impl Frame {
             self.stroke_tessellator.tessellate_path(
                 path.raw(),
                 &options,
-                &mut buffers,
+                &mut buffer,
             )
         } else {
             let path = path.transformed(&self.transforms.current.raw);
@@ -213,13 +232,10 @@ impl Frame {
             self.stroke_tessellator.tessellate_path(
                 path.raw(),
                 &options,
-                &mut buffers,
+                &mut buffer,
             )
         }
         .expect("Stroke path");
-
-        self.buffers
-            .push((buf, stroke.style.as_mesh_style(&self.transforms.current)))
     }
 
     /// Draws the characters of the given [`Text`] on the [`Frame`], filling
@@ -361,7 +377,7 @@ impl Frame {
     }
 
     fn into_primitives(mut self) -> Vec<Primitive> {
-        for (buffer, style) in self.buffers {
+        for (buffer, style) in self.buffers.stack {
             if !buffer.indices.is_empty() {
                 self.primitives.push(Primitive::Mesh2D {
                     buffers: triangle::Mesh2D {