Implement Canvas support for iced_tiny_skia

graphics/src/primitive.rs

@@ -1,23 +1,15 @@
+use crate::alignment;
+
 use iced_native::image;
 use iced_native::svg;
-use iced_native::{Background, Color, Font, Rectangle, Size, Vector};
-
-use crate::alignment;
-use crate::gradient::Gradient;
-use crate::triangle;
+use iced_native::{Background, Color, Font, Gradient, Rectangle, Size, Vector};
 
+use bytemuck::{Pod, Zeroable};
 use std::sync::Arc;
 
 /// A rendering primitive.
 #[derive(Debug, Clone)]
 pub enum Primitive {
-    /// An empty primitive
-    None,
-    /// A group of primitives
-    Group {
-        /// The primitives of the group
-        primitives: Vec<Primitive>,
-    },
     /// A text primitive
     Text {
         /// The contents of the text
@@ -66,6 +58,50 @@ pub enum Primitive {
         /// The bounds of the viewport
         bounds: Rectangle,
     },
+    /// A low-level primitive to render a mesh of triangles with a solid color.
+    ///
+    /// It can be used to render many kinds of geometry freely.
+    SolidMesh {
+        /// The vertices and indices of the mesh.
+        buffers: Mesh2D<ColoredVertex2D>,
+
+        /// The size of the drawable region of the mesh.
+        ///
+        /// Any geometry that falls out of this region will be clipped.
+        size: Size,
+    },
+    /// A low-level primitive to render a mesh of triangles with a gradient.
+    ///
+    /// It can be used to render many kinds of geometry freely.
+    GradientMesh {
+        /// The vertices and indices of the mesh.
+        buffers: Mesh2D<Vertex2D>,
+
+        /// The size of the drawable region of the mesh.
+        ///
+        /// Any geometry that falls out of this region will be clipped.
+        size: Size,
+
+        /// The [`Gradient`] to apply to the mesh.
+        gradient: Gradient,
+    },
+    Fill {
+        path: tiny_skia::Path,
+        paint: tiny_skia::Paint<'static>,
+        rule: tiny_skia::FillRule,
+        transform: tiny_skia::Transform,
+    },
+    Stroke {
+        path: tiny_skia::Path,
+        paint: tiny_skia::Paint<'static>,
+        stroke: tiny_skia::Stroke,
+        transform: tiny_skia::Transform,
+    },
+    /// A group of primitives
+    Group {
+        /// The primitives of the group
+        primitives: Vec<Primitive>,
+    },
     /// A clip primitive
     Clip {
         /// The bounds of the clip
@@ -81,45 +117,69 @@ pub enum Primitive {
         /// The primitive to translate
         content: Box<Primitive>,
     },
-    /// A low-level primitive to render a mesh of triangles with a solid color.
-    ///
-    /// It can be used to render many kinds of geometry freely.
-    SolidMesh {
-        /// The vertices and indices of the mesh.
-        buffers: triangle::Mesh2D<triangle::ColoredVertex2D>,
-
-        /// The size of the drawable region of the mesh.
-        ///
-        /// Any geometry that falls out of this region will be clipped.
-        size: Size,
-    },
-    /// A low-level primitive to render a mesh of triangles with a gradient.
-    ///
-    /// It can be used to render many kinds of geometry freely.
-    GradientMesh {
-        /// The vertices and indices of the mesh.
-        buffers: triangle::Mesh2D<triangle::Vertex2D>,
-
-        /// The size of the drawable region of the mesh.
-        ///
-        /// Any geometry that falls out of this region will be clipped.
-        size: Size,
-
-        /// The [`Gradient`] to apply to the mesh.
-        gradient: Gradient,
-    },
     /// A cached primitive.
     ///
     /// This can be useful if you are implementing a widget where primitive
     /// generation is expensive.
-    Cached {
+    Cache {
         /// The cached primitive
-        cache: Arc<Primitive>,
+        content: Arc<Primitive>,
     },
 }
 
-impl Default for Primitive {
-    fn default() -> Primitive {
-        Primitive::None
+impl Primitive {
+    pub fn group(primitives: Vec<Self>) -> Self {
+        Self::Group { primitives }
+    }
+
+    pub fn clip(self, bounds: Rectangle) -> Self {
+        Self::Clip {
+            bounds,
+            content: Box::new(self),
+        }
+    }
+
+    pub fn translate(self, translation: Vector) -> Self {
+        Self::Translate {
+            translation,
+            content: Box::new(self),
+        }
+    }
+}
+
+/// A set of [`Vertex2D`] and indices representing a list of triangles.
+#[derive(Clone, Debug)]
+pub struct Mesh2D<T> {
+    /// The vertices of the mesh
+    pub vertices: Vec<T>,
+
+    /// The list of vertex indices that defines the triangles of the mesh.
+    ///
+    /// Therefore, this list should always have a length that is a multiple of 3.
+    pub indices: Vec<u32>,
+}
+
+/// A two-dimensional vertex.
+#[derive(Copy, Clone, Debug, Zeroable, Pod)]
+#[repr(C)]
+pub struct Vertex2D {
+    /// The vertex position in 2D space.
+    pub position: [f32; 2],
+}
+
+/// A two-dimensional vertex with a color.
+#[derive(Copy, Clone, Debug, Zeroable, Pod)]
+#[repr(C)]
+pub struct ColoredVertex2D {
+    /// The vertex position in 2D space.
+    pub position: [f32; 2],
+
+    /// The color of the vertex in __linear__ RGBA.
+    pub color: [f32; 4],
+}
+
+impl From<()> for Primitive {
+    fn from(_: ()) -> Self {
+        Self::Group { primitives: vec![] }
     }
 }