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Diffstat (limited to 'wgpu/src/widget/canvas/frame.rs')
| -rw-r--r-- | wgpu/src/widget/canvas/frame.rs | 255 |
1 files changed, 255 insertions, 0 deletions
diff --git a/wgpu/src/widget/canvas/frame.rs b/wgpu/src/widget/canvas/frame.rs new file mode 100644 index 00000000..fa6d8c0a --- /dev/null +++ b/wgpu/src/widget/canvas/frame.rs @@ -0,0 +1,255 @@ +use iced_native::{Point, Size, Vector}; + +use crate::{ + canvas::{Fill, Path, Stroke}, + triangle, +}; + +/// The frame of a [`Canvas`]. +/// +/// [`Canvas`]: struct.Canvas.html +#[derive(Debug)] +pub struct Frame { + width: f32, + height: f32, + buffers: lyon::tessellation::VertexBuffers<triangle::Vertex2D, u32>, + transforms: Transforms, +} + +#[derive(Debug)] +struct Transforms { + previous: Vec<Transform>, + current: Transform, +} + +#[derive(Debug, Clone, Copy)] +struct Transform { + raw: lyon::math::Transform, + is_identity: bool, +} + +impl Frame { + /// Creates a new empty [`Frame`] with the given dimensions. + /// + /// The default coordinate system of a [`Frame`] has its origin at the + /// top-left corner of its bounds. + /// + /// [`Frame`]: struct.Frame.html + pub fn new(width: f32, height: f32) -> Frame { + Frame { + width, + height, + buffers: lyon::tessellation::VertexBuffers::new(), + transforms: Transforms { + previous: Vec::new(), + current: Transform { + raw: lyon::math::Transform::identity(), + is_identity: true, + }, + }, + } + } + + /// Returns the width of the [`Frame`]. + /// + /// [`Frame`]: struct.Frame.html + #[inline] + pub fn width(&self) -> f32 { + self.width + } + + /// Returns the width of the [`Frame`]. + /// + /// [`Frame`]: struct.Frame.html + #[inline] + pub fn height(&self) -> f32 { + self.height + } + + /// Returns the dimensions of the [`Frame`]. + /// + /// [`Frame`]: struct.Frame.html + #[inline] + pub fn size(&self) -> Size { + Size::new(self.width, self.height) + } + + /// Returns the coordinate of the center of the [`Frame`]. + /// + /// [`Frame`]: struct.Frame.html + #[inline] + pub fn center(&self) -> Point { + Point::new(self.width / 2.0, self.height / 2.0) + } + + /// Draws the given [`Path`] on the [`Frame`] by filling it with the + /// provided style. + /// + /// [`Path`]: path/struct.Path.html + /// [`Frame`]: struct.Frame.html + pub fn fill(&mut self, path: &Path, fill: Fill) { + use lyon::tessellation::{ + BuffersBuilder, FillOptions, FillTessellator, + }; + + let mut buffers = BuffersBuilder::new( + &mut self.buffers, + FillVertex(match fill { + Fill::Color(color) => color.into_linear(), + }), + ); + + let mut tessellator = FillTessellator::new(); + + let result = if self.transforms.current.is_identity { + tessellator.tessellate_path( + path.raw(), + &FillOptions::default(), + &mut buffers, + ) + } else { + let path = path.transformed(&self.transforms.current.raw); + + tessellator.tessellate_path( + path.raw(), + &FillOptions::default(), + &mut buffers, + ) + }; + + let _ = result.expect("Tessellate path"); + } + + /// Draws the stroke of the given [`Path`] on the [`Frame`] with the + /// provided style. + /// + /// [`Path`]: path/struct.Path.html + /// [`Frame`]: struct.Frame.html + pub fn stroke(&mut self, path: &Path, stroke: Stroke) { + use lyon::tessellation::{ + BuffersBuilder, StrokeOptions, StrokeTessellator, + }; + + let mut buffers = BuffersBuilder::new( + &mut self.buffers, + StrokeVertex(stroke.color.into_linear()), + ); + + let mut tessellator = StrokeTessellator::new(); + + let mut options = StrokeOptions::default(); + options.line_width = stroke.width; + options.start_cap = stroke.line_cap.into(); + options.end_cap = stroke.line_cap.into(); + options.line_join = stroke.line_join.into(); + + let result = if self.transforms.current.is_identity { + tessellator.tessellate_path(path.raw(), &options, &mut buffers) + } else { + let path = path.transformed(&self.transforms.current.raw); + + tessellator.tessellate_path(path.raw(), &options, &mut buffers) + }; + + let _ = result.expect("Stroke path"); + } + + /// Stores the current transform of the [`Frame`] and executes the given + /// drawing operations, restoring the transform afterwards. + /// + /// This method is useful to compose transforms and perform drawing + /// operations in different coordinate systems. + /// + /// [`Frame`]: struct.Frame.html + #[inline] + pub fn with_save(&mut self, f: impl FnOnce(&mut Frame)) { + self.transforms.previous.push(self.transforms.current); + + f(self); + + self.transforms.current = self.transforms.previous.pop().unwrap(); + } + + /// Applies a translation to the current transform of the [`Frame`]. + /// + /// [`Frame`]: struct.Frame.html + #[inline] + pub fn translate(&mut self, translation: Vector) { + self.transforms.current.raw = self + .transforms + .current + .raw + .pre_translate(lyon::math::Vector::new( + translation.x, + translation.y, + )); + self.transforms.current.is_identity = false; + } + + /// Applies a rotation to the current transform of the [`Frame`]. + /// + /// [`Frame`]: struct.Frame.html + #[inline] + pub fn rotate(&mut self, angle: f32) { + self.transforms.current.raw = self + .transforms + .current + .raw + .pre_rotate(lyon::math::Angle::radians(-angle)); + self.transforms.current.is_identity = false; + } + + /// Applies a scaling to the current transform of the [`Frame`]. + /// + /// [`Frame`]: struct.Frame.html + #[inline] + pub fn scale(&mut self, scale: f32) { + self.transforms.current.raw = + self.transforms.current.raw.pre_scale(scale, scale); + self.transforms.current.is_identity = false; + } + + /// Produces the geometry that has been drawn on the [`Frame`]. + /// + /// [`Frame`]: struct.Frame.html + pub fn into_mesh(self) -> triangle::Mesh2D { + triangle::Mesh2D { + vertices: self.buffers.vertices, + indices: self.buffers.indices, + } + } +} + +struct FillVertex([f32; 4]); + +impl lyon::tessellation::FillVertexConstructor<triangle::Vertex2D> + for FillVertex +{ + fn new_vertex( + &mut self, + position: lyon::math::Point, + _attributes: lyon::tessellation::FillAttributes<'_>, + ) -> triangle::Vertex2D { + triangle::Vertex2D { + position: [position.x, position.y], + color: self.0, + } + } +} + +struct StrokeVertex([f32; 4]); + +impl lyon::tessellation::StrokeVertexConstructor<triangle::Vertex2D> + for StrokeVertex +{ + fn new_vertex( + &mut self, + position: lyon::math::Point, + _attributes: lyon::tessellation::StrokeAttributes<'_, '_>, + ) -> triangle::Vertex2D { + triangle::Vertex2D { + position: [position.x, position.y], + color: self.0, + } + } +} |