Implement Canvas support for iced_tiny_skia

wgpu/src/layer/mesh.rs

@@ -0,0 +1,93 @@
+//! A collection of triangle primitives.
+use crate::primitive;
+use crate::{Gradient, Point, Rectangle};
+
+/// A mesh of triangles.
+#[derive(Debug, Clone, Copy)]
+pub enum Mesh<'a> {
+    /// A mesh of triangles with a solid color.
+    Solid {
+        /// The origin of the vertices of the [`Mesh`].
+        origin: Point,
+
+        /// The vertex and index buffers of the [`Mesh`].
+        buffers: &'a primitive::Mesh2D<primitive::ColoredVertex2D>,
+
+        /// The clipping bounds of the [`Mesh`].
+        clip_bounds: Rectangle<f32>,
+    },
+    /// A mesh of triangles with a gradient color.
+    Gradient {
+        /// The origin of the vertices of the [`Mesh`].
+        origin: Point,
+
+        /// The vertex and index buffers of the [`Mesh`].
+        buffers: &'a primitive::Mesh2D<primitive::Vertex2D>,
+
+        /// The clipping bounds of the [`Mesh`].
+        clip_bounds: Rectangle<f32>,
+
+        /// The gradient to apply to the [`Mesh`].
+        gradient: &'a Gradient,
+    },
+}
+
+impl Mesh<'_> {
+    /// Returns the origin of the [`Mesh`].
+    pub fn origin(&self) -> Point {
+        match self {
+            Self::Solid { origin, .. } | Self::Gradient { origin, .. } => {
+                *origin
+            }
+        }
+    }
+
+    /// Returns the indices of the [`Mesh`].
+    pub fn indices(&self) -> &[u32] {
+        match self {
+            Self::Solid { buffers, .. } => &buffers.indices,
+            Self::Gradient { buffers, .. } => &buffers.indices,
+        }
+    }
+
+    /// Returns the clip bounds of the [`Mesh`].
+    pub fn clip_bounds(&self) -> Rectangle<f32> {
+        match self {
+            Self::Solid { clip_bounds, .. }
+            | Self::Gradient { clip_bounds, .. } => *clip_bounds,
+        }
+    }
+}
+
+/// The result of counting the attributes of a set of meshes.
+#[derive(Debug, Clone, Copy, Default)]
+pub struct AttributeCount {
+    /// The total amount of solid vertices.
+    pub solid_vertices: usize,
+
+    /// The total amount of gradient vertices.
+    pub gradient_vertices: usize,
+
+    /// The total amount of indices.
+    pub indices: usize,
+}
+
+/// Returns the number of total vertices & total indices of all [`Mesh`]es.
+pub fn attribute_count_of<'a>(meshes: &'a [Mesh<'a>]) -> AttributeCount {
+    meshes
+        .iter()
+        .fold(AttributeCount::default(), |mut count, mesh| {
+            match mesh {
+                Mesh::Solid { buffers, .. } => {
+                    count.solid_vertices += buffers.vertices.len();
+                    count.indices += buffers.indices.len();
+                }
+                Mesh::Gradient { buffers, .. } => {
+                    count.gradient_vertices += buffers.vertices.len();
+                    count.indices += buffers.indices.len();
+                }
+            }
+
+            count
+        })
+}