Move `Canvas` and `QRCode` to `iced` crate

Rename `canvas` modules to `geometry` in graphics subcrates

1 files changed, 608 insertions, 0 deletions

diff --git a/wgpu/src/geometry.rs b/wgpu/src/geometry.rs
new file mode 100644
index 00000000..11e8126f
--- /dev/null
+++ b/wgpu/src/geometry.rs
@@ -0,0 +1,608 @@
+use iced_graphics::geometry::fill::{self, Fill};
+use iced_graphics::geometry::{
+    LineCap, LineDash, LineJoin, Path, Stroke, Style, Text,
+};
+use iced_graphics::primitive::{self, Primitive};
+use iced_graphics::{Gradient, Point, Rectangle, Size, Vector};
+
+use lyon::geom::euclid;
+use lyon::tessellation;
+use std::borrow::Cow;
+
+/// The frame of a [`Canvas`].
+///
+/// [`Canvas`]: crate::widget::Canvas
+#[allow(missing_debug_implementations)]
+pub struct Frame {
+    size: Size,
+    buffers: BufferStack,
+    primitives: Vec<Primitive>,
+    transforms: Transforms,
+    fill_tessellator: tessellation::FillTessellator,
+    stroke_tessellator: tessellation::StrokeTessellator,
+}
+
+enum Buffer {
+    Solid(tessellation::VertexBuffers<primitive::ColoredVertex2D, u32>),
+    Gradient(
+        tessellation::VertexBuffers<primitive::Vertex2D, u32>,
+        Gradient,
+    ),
+}
+
+struct BufferStack {
+    stack: Vec<Buffer>,
+}
+
+impl BufferStack {
+    fn new() -> Self {
+        Self { stack: Vec::new() }
+    }
+
+    fn get_mut(&mut self, style: &Style) -> &mut Buffer {
+        match style {
+            Style::Solid(_) => match self.stack.last() {
+                Some(Buffer::Solid(_)) => {}
+                _ => {
+                    self.stack.push(Buffer::Solid(
+                        tessellation::VertexBuffers::new(),
+                    ));
+                }
+            },
+            Style::Gradient(gradient) => match self.stack.last() {
+                Some(Buffer::Gradient(_, last)) if gradient == last => {}
+                _ => {
+                    self.stack.push(Buffer::Gradient(
+                        tessellation::VertexBuffers::new(),
+                        gradient.clone(),
+                    ));
+                }
+            },
+        }
+
+        self.stack.last_mut().unwrap()
+    }
+
+    fn get_fill<'a>(
+        &'a mut self,
+        style: &Style,
+    ) -> Box<dyn tessellation::FillGeometryBuilder + 'a> {
+        match (style, self.get_mut(style)) {
+            (Style::Solid(color), Buffer::Solid(buffer)) => {
+                Box::new(tessellation::BuffersBuilder::new(
+                    buffer,
+                    TriangleVertex2DBuilder(color.into_linear()),
+                ))
+            }
+            (Style::Gradient(_), Buffer::Gradient(buffer, _)) => Box::new(
+                tessellation::BuffersBuilder::new(buffer, Vertex2DBuilder),
+            ),
+            _ => unreachable!(),
+        }
+    }
+
+    fn get_stroke<'a>(
+        &'a mut self,
+        style: &Style,
+    ) -> Box<dyn tessellation::StrokeGeometryBuilder + 'a> {
+        match (style, self.get_mut(style)) {
+            (Style::Solid(color), Buffer::Solid(buffer)) => {
+                Box::new(tessellation::BuffersBuilder::new(
+                    buffer,
+                    TriangleVertex2DBuilder(color.into_linear()),
+                ))
+            }
+            (Style::Gradient(_), Buffer::Gradient(buffer, _)) => Box::new(
+                tessellation::BuffersBuilder::new(buffer, Vertex2DBuilder),
+            ),
+            _ => unreachable!(),
+        }
+    }
+}
+
+#[derive(Debug)]
+struct Transforms {
+    previous: Vec<Transform>,
+    current: Transform,
+}
+
+#[derive(Debug, Clone, Copy)]
+struct Transform {
+    raw: lyon::math::Transform,
+    is_identity: bool,
+}
+
+impl Transform {
+    /// Transforms the given [Point] by the transformation matrix.
+    fn transform_point(&self, point: &mut Point) {
+        let transformed = self
+            .raw
+            .transform_point(euclid::Point2D::new(point.x, point.y));
+        point.x = transformed.x;
+        point.y = transformed.y;
+    }
+
+    fn transform_style(&self, style: Style) -> Style {
+        match style {
+            Style::Solid(color) => Style::Solid(color),
+            Style::Gradient(gradient) => {
+                Style::Gradient(self.transform_gradient(gradient))
+            }
+        }
+    }
+
+    fn transform_gradient(&self, mut gradient: Gradient) -> Gradient {
+        let (start, end) = match &mut gradient {
+            Gradient::Linear(linear) => (&mut linear.start, &mut linear.end),
+        };
+        self.transform_point(start);
+        self.transform_point(end);
+        gradient
+    }
+}
+
+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.
+    pub fn new(size: Size) -> Frame {
+        Frame {
+            size,
+            buffers: BufferStack::new(),
+            primitives: Vec::new(),
+            transforms: Transforms {
+                previous: Vec::new(),
+                current: Transform {
+                    raw: lyon::math::Transform::identity(),
+                    is_identity: true,
+                },
+            },
+            fill_tessellator: tessellation::FillTessellator::new(),
+            stroke_tessellator: tessellation::StrokeTessellator::new(),
+        }
+    }
+
+    /// Returns the width of the [`Frame`].
+    #[inline]
+    pub fn width(&self) -> f32 {
+        self.size.width
+    }
+
+    /// Returns the height of the [`Frame`].
+    #[inline]
+    pub fn height(&self) -> f32 {
+        self.size.height
+    }
+
+    /// Returns the dimensions of the [`Frame`].
+    #[inline]
+    pub fn size(&self) -> Size {
+        self.size
+    }
+
+    /// Returns the coordinate of the center of the [`Frame`].
+    #[inline]
+    pub fn center(&self) -> Point {
+        Point::new(self.size.width / 2.0, self.size.height / 2.0)
+    }
+
+    /// Draws the given [`Path`] on the [`Frame`] by filling it with the
+    /// provided style.
+    pub fn fill(&mut self, path: &Path, fill: impl Into<Fill>) {
+        let Fill { style, rule } = fill.into();
+
+        let mut buffer = self
+            .buffers
+            .get_fill(&self.transforms.current.transform_style(style));
+
+        let options = tessellation::FillOptions::default()
+            .with_fill_rule(into_fill_rule(rule));
+
+        if self.transforms.current.is_identity {
+            self.fill_tessellator.tessellate_path(
+                path.raw(),
+                &options,
+                buffer.as_mut(),
+            )
+        } else {
+            let path = path.transform(&self.transforms.current.raw);
+
+            self.fill_tessellator.tessellate_path(
+                path.raw(),
+                &options,
+                buffer.as_mut(),
+            )
+        }
+        .expect("Tessellate path.");
+    }
+
+    /// Draws an axis-aligned rectangle given its top-left corner coordinate and
+    /// its `Size` on the [`Frame`] by filling it with the provided style.
+    pub fn fill_rectangle(
+        &mut self,
+        top_left: Point,
+        size: Size,
+        fill: impl Into<Fill>,
+    ) {
+        let Fill { style, rule } = fill.into();
+
+        let mut buffer = self
+            .buffers
+            .get_fill(&self.transforms.current.transform_style(style));
+
+        let top_left =
+            self.transforms.current.raw.transform_point(
+                lyon::math::Point::new(top_left.x, top_left.y),
+            );
+
+        let size =
+            self.transforms.current.raw.transform_vector(
+                lyon::math::Vector::new(size.width, size.height),
+            );
+
+        let options = tessellation::FillOptions::default()
+            .with_fill_rule(into_fill_rule(rule));
+
+        self.fill_tessellator
+            .tessellate_rectangle(
+                &lyon::math::Box2D::new(top_left, top_left + size),
+                &options,
+                buffer.as_mut(),
+            )
+            .expect("Fill rectangle");
+    }
+
+    /// Draws the stroke of the given [`Path`] on the [`Frame`] with the
+    /// provided style.
+    pub fn stroke<'a>(&mut self, path: &Path, stroke: impl Into<Stroke<'a>>) {
+        let stroke = stroke.into();
+
+        let mut buffer = self
+            .buffers
+            .get_stroke(&self.transforms.current.transform_style(stroke.style));
+
+        let mut options = tessellation::StrokeOptions::default();
+        options.line_width = stroke.width;
+        options.start_cap = into_line_cap(stroke.line_cap);
+        options.end_cap = into_line_cap(stroke.line_cap);
+        options.line_join = into_line_join(stroke.line_join);
+
+        let path = if stroke.line_dash.segments.is_empty() {
+            Cow::Borrowed(path)
+        } else {
+            Cow::Owned(dashed(path, stroke.line_dash))
+        };
+
+        if self.transforms.current.is_identity {
+            self.stroke_tessellator.tessellate_path(
+                path.raw(),
+                &options,
+                buffer.as_mut(),
+            )
+        } else {
+            let path = path.transform(&self.transforms.current.raw);
+
+            self.stroke_tessellator.tessellate_path(
+                path.raw(),
+                &options,
+                buffer.as_mut(),
+            )
+        }
+        .expect("Stroke path");
+    }
+
+    /// Draws the characters of the given [`Text`] on the [`Frame`], filling
+    /// them with the given color.
+    ///
+    /// __Warning:__ Text currently does not work well with rotations and scale
+    /// transforms! The position will be correctly transformed, but the
+    /// resulting glyphs will not be rotated or scaled properly.
+    ///
+    /// Additionally, all text will be rendered on top of all the layers of
+    /// a [`Canvas`]. Therefore, it is currently only meant to be used for
+    /// overlays, which is the most common use case.
+    ///
+    /// Support for vectorial text is planned, and should address all these
+    /// limitations.
+    ///
+    /// [`Canvas`]: crate::widget::Canvas
+    pub fn fill_text(&mut self, text: impl Into<Text>) {
+        let text = text.into();
+
+        let position = if self.transforms.current.is_identity {
+            text.position
+        } else {
+            let transformed = self.transforms.current.raw.transform_point(
+                lyon::math::Point::new(text.position.x, text.position.y),
+            );
+
+            Point::new(transformed.x, transformed.y)
+        };
+
+        // TODO: Use vectorial text instead of primitive
+        self.primitives.push(Primitive::Text {
+            content: text.content,
+            bounds: Rectangle {
+                x: position.x,
+                y: position.y,
+                width: f32::INFINITY,
+                height: f32::INFINITY,
+            },
+            color: text.color,
+            size: text.size,
+            font: text.font,
+            horizontal_alignment: text.horizontal_alignment,
+            vertical_alignment: text.vertical_alignment,
+        });
+    }
+
+    /// 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.
+    #[inline]
+    pub fn with_save(&mut self, f: impl FnOnce(&mut Frame)) {
+        self.push_transform();
+
+        f(self);
+
+        self.pop_transform();
+    }
+
+    pub fn push_transform(&mut self) {
+        self.transforms.previous.push(self.transforms.current);
+    }
+
+    pub fn pop_transform(&mut self) {
+        self.transforms.current = self.transforms.previous.pop().unwrap();
+    }
+
+    /// Executes the given drawing operations within a [`Rectangle`] region,
+    /// clipping any geometry that overflows its bounds. Any transformations
+    /// performed are local to the provided closure.
+    ///
+    /// This method is useful to perform drawing operations that need to be
+    /// clipped.
+    #[inline]
+    pub fn with_clip(&mut self, region: Rectangle, f: impl FnOnce(&mut Frame)) {
+        let mut frame = Frame::new(region.size());
+
+        f(&mut frame);
+
+        let translation = Vector::new(region.x, region.y);
+
+        self.clip(frame, translation);
+    }
+
+    pub fn clip(&mut self, frame: Frame, translation: Vector) {
+        let size = frame.size();
+        let primitives = frame.into_primitives();
+
+        let (text, meshes) = primitives
+            .into_iter()
+            .partition(|primitive| matches!(primitive, Primitive::Text { .. }));
+
+        self.primitives.push(Primitive::Group {
+            primitives: vec![
+                Primitive::Translate {
+                    translation,
+                    content: Box::new(Primitive::Group { primitives: meshes }),
+                },
+                Primitive::Translate {
+                    translation,
+                    content: Box::new(Primitive::Clip {
+                        bounds: Rectangle::with_size(size),
+                        content: Box::new(Primitive::Group {
+                            primitives: text,
+                        }),
+                    }),
+                },
+            ],
+        });
+    }
+
+    /// Applies a translation to the current transform of the [`Frame`].
+    #[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 in radians to the current transform of the [`Frame`].
+    #[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`].
+    #[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 [`Primitive`] representing everything drawn on the [`Frame`].
+    pub fn into_primitive(self) -> Primitive {
+        Primitive::Group {
+            primitives: self.into_primitives(),
+        }
+    }
+
+    fn into_primitives(mut self) -> Vec<Primitive> {
+        for buffer in self.buffers.stack {
+            match buffer {
+                Buffer::Solid(buffer) => {
+                    if !buffer.indices.is_empty() {
+                        self.primitives.push(Primitive::SolidMesh {
+                            buffers: primitive::Mesh2D {
+                                vertices: buffer.vertices,
+                                indices: buffer.indices,
+                            },
+                            size: self.size,
+                        })
+                    }
+                }
+                Buffer::Gradient(buffer, gradient) => {
+                    if !buffer.indices.is_empty() {
+                        self.primitives.push(Primitive::GradientMesh {
+                            buffers: primitive::Mesh2D {
+                                vertices: buffer.vertices,
+                                indices: buffer.indices,
+                            },
+                            size: self.size,
+                            gradient,
+                        })
+                    }
+                }
+            }
+        }
+
+        self.primitives
+    }
+}
+
+struct Vertex2DBuilder;
+
+impl tessellation::FillVertexConstructor<primitive::Vertex2D>
+    for Vertex2DBuilder
+{
+    fn new_vertex(
+        &mut self,
+        vertex: tessellation::FillVertex<'_>,
+    ) -> primitive::Vertex2D {
+        let position = vertex.position();
+
+        primitive::Vertex2D {
+            position: [position.x, position.y],
+        }
+    }
+}
+
+impl tessellation::StrokeVertexConstructor<primitive::Vertex2D>
+    for Vertex2DBuilder
+{
+    fn new_vertex(
+        &mut self,
+        vertex: tessellation::StrokeVertex<'_, '_>,
+    ) -> primitive::Vertex2D {
+        let position = vertex.position();
+
+        primitive::Vertex2D {
+            position: [position.x, position.y],
+        }
+    }
+}
+
+struct TriangleVertex2DBuilder([f32; 4]);
+
+impl tessellation::FillVertexConstructor<primitive::ColoredVertex2D>
+    for TriangleVertex2DBuilder
+{
+    fn new_vertex(
+        &mut self,
+        vertex: tessellation::FillVertex<'_>,
+    ) -> primitive::ColoredVertex2D {
+        let position = vertex.position();
+
+        primitive::ColoredVertex2D {
+            position: [position.x, position.y],
+            color: self.0,
+        }
+    }
+}
+
+impl tessellation::StrokeVertexConstructor<primitive::ColoredVertex2D>
+    for TriangleVertex2DBuilder
+{
+    fn new_vertex(
+        &mut self,
+        vertex: tessellation::StrokeVertex<'_, '_>,
+    ) -> primitive::ColoredVertex2D {
+        let position = vertex.position();
+
+        primitive::ColoredVertex2D {
+            position: [position.x, position.y],
+            color: self.0,
+        }
+    }
+}
+
+fn into_line_join(line_join: LineJoin) -> lyon::tessellation::LineJoin {
+    match line_join {
+        LineJoin::Miter => lyon::tessellation::LineJoin::Miter,
+        LineJoin::Round => lyon::tessellation::LineJoin::Round,
+        LineJoin::Bevel => lyon::tessellation::LineJoin::Bevel,
+    }
+}
+
+fn into_line_cap(line_cap: LineCap) -> lyon::tessellation::LineCap {
+    match line_cap {
+        LineCap::Butt => lyon::tessellation::LineCap::Butt,
+        LineCap::Square => lyon::tessellation::LineCap::Square,
+        LineCap::Round => lyon::tessellation::LineCap::Round,
+    }
+}
+
+fn into_fill_rule(rule: fill::Rule) -> lyon::tessellation::FillRule {
+    match rule {
+        fill::Rule::NonZero => lyon::tessellation::FillRule::NonZero,
+        fill::Rule::EvenOdd => lyon::tessellation::FillRule::EvenOdd,
+    }
+}
+
+pub(super) fn dashed(path: &Path, line_dash: LineDash<'_>) -> Path {
+    use lyon::algorithms::walk::{
+        walk_along_path, RepeatedPattern, WalkerEvent,
+    };
+    use lyon::path::iterator::PathIterator;
+
+    Path::new(|builder| {
+        let segments_odd = (line_dash.segments.len() % 2 == 1)
+            .then(|| [line_dash.segments, line_dash.segments].concat());
+
+        let mut draw_line = false;
+
+        walk_along_path(
+            path.raw().iter().flattened(0.01),
+            0.0,
+            lyon::tessellation::StrokeOptions::DEFAULT_TOLERANCE,
+            &mut RepeatedPattern {
+                callback: |event: WalkerEvent<'_>| {
+                    let point = Point {
+                        x: event.position.x,
+                        y: event.position.y,
+                    };
+
+                    if draw_line {
+                        builder.line_to(point);
+                    } else {
+                        builder.move_to(point);
+                    }
+
+                    draw_line = !draw_line;
+
+                    true
+                },
+                index: line_dash.offset,
+                intervals: segments_odd
+                    .as_deref()
+                    .unwrap_or(line_dash.segments),
+            },
+        );
+    })
+}