5 files changed, 84 insertions, 29 deletions

diff --git a/graphics/src/widget/canvas.rs b/graphics/src/widget/canvas.rs
index f9722f33..65d7e37e 100644
--- a/graphics/src/widget/canvas.rs
+++ b/graphics/src/widget/canvas.rs
@@ -9,10 +9,9 @@ use crate::{Backend, Primitive};
 use iced_native::layout;
 use iced_native::mouse;
 use iced_native::{
-    Clipboard, Element, Hasher, Layout, Length, Point, Rectangle, Shell, Size,
-    Vector, Widget,
+    Clipboard, Element, Layout, Length, Point, Rectangle, Shell, Size, Vector,
+    Widget,
 };
-use std::hash::Hash;
 use std::marker::PhantomData;
 
 pub mod event;
@@ -35,7 +34,7 @@ pub use frame::Frame;
 pub use geometry::Geometry;
 pub use path::Path;
 pub use program::Program;
-pub use stroke::{LineCap, LineJoin, Stroke};
+pub use stroke::{LineCap, LineDash, LineJoin, Stroke};
 pub use text::Text;
 
 /// A widget capable of drawing 2D graphics.
@@ -212,6 +211,11 @@ where
         use iced_native::Renderer as _;
 
         let bounds = layout.bounds();
+
+        if bounds.width < 1.0 || bounds.height < 1.0 {
+            return;
+        }
+
         let translation = Vector::new(bounds.x, bounds.y);
         let cursor = Cursor::from_window_position(cursor_position);
 
@@ -226,14 +230,6 @@ where
             });
         });
     }
-
-    fn hash_layout(&self, state: &mut Hasher) {
-        struct Marker;
-        std::any::TypeId::of::<Marker>().hash(state);
-
-        self.width.hash(state);
-        self.height.hash(state);
-    }
 }
 
 impl<'a, Message, P, B> From<Canvas<Message, P>>
diff --git a/graphics/src/widget/canvas/frame.rs b/graphics/src/widget/canvas/frame.rs
index 08518f40..a3449605 100644
--- a/graphics/src/widget/canvas/frame.rs
+++ b/graphics/src/widget/canvas/frame.rs
@@ -1,6 +1,9 @@
+use std::borrow::Cow;
+
 use iced_native::{Point, Rectangle, Size, Vector};
 
 use crate::{
+    canvas::path,
     canvas::{Fill, Geometry, Path, Stroke, Text},
     triangle, Primitive,
 };
@@ -150,7 +153,7 @@ impl Frame {
 
     /// Draws the stroke of the given [`Path`] on the [`Frame`] with the
     /// provided style.
-    pub fn stroke(&mut self, path: &Path, stroke: impl Into<Stroke>) {
+    pub fn stroke<'a>(&mut self, path: &Path, stroke: impl Into<Stroke<'a>>) {
         let stroke = stroke.into();
 
         let mut buffers = tessellation::BuffersBuilder::new(
@@ -164,6 +167,12 @@ impl Frame {
         options.end_cap = stroke.line_cap.into();
         options.line_join = stroke.line_join.into();
 
+        let path = if stroke.line_dash.segments.is_empty() {
+            Cow::Borrowed(path)
+        } else {
+            Cow::Owned(path::dashed(path, stroke.line_dash))
+        };
+
         let result = if self.transforms.current.is_identity {
             self.stroke_tessellator.tessellate_path(
                 path.raw(),
diff --git a/graphics/src/widget/canvas/path.rs b/graphics/src/widget/canvas/path.rs
index 4e4fd734..1728f060 100644
--- a/graphics/src/widget/canvas/path.rs
+++ b/graphics/src/widget/canvas/path.rs
@@ -7,7 +7,11 @@ mod builder;
 pub use arc::Arc;
 pub use builder::Builder;
 
+use crate::canvas::LineDash;
+
 use iced_native::{Point, Size};
+use lyon::algorithms::walk::{walk_along_path, RepeatedPattern};
+use lyon::path::iterator::PathIterator;
 
 /// An immutable set of points that may or may not be connected.
 ///
@@ -66,3 +70,43 @@ impl Path {
         }
     }
 }
+
+pub(super) fn dashed(path: &Path, line_dash: LineDash<'_>) -> Path {
+    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,
+            &mut RepeatedPattern {
+                callback: |position: lyon::algorithms::math::Point,
+                           _tangent,
+                           _distance| {
+                    let point = Point {
+                        x: position.x,
+                        y: 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_ref()
+                    .map(Vec::as_slice)
+                    .unwrap_or(line_dash.segments),
+            },
+        );
+    })
+}
diff --git a/graphics/src/widget/canvas/stroke.rs b/graphics/src/widget/canvas/stroke.rs
index 9f0449d0..6accc2fb 100644
--- a/graphics/src/widget/canvas/stroke.rs
+++ b/graphics/src/widget/canvas/stroke.rs
@@ -2,7 +2,7 @@ use iced_native::Color;
 
 /// The style of a stroke.
 #[derive(Debug, Clone, Copy)]
-pub struct Stroke {
+pub struct Stroke<'a> {
     /// The color of the stroke.
     pub color: Color,
     /// The distance between the two edges of the stroke.
@@ -12,37 +12,40 @@ pub struct Stroke {
     /// The shape to be used at the corners of paths or basic shapes when they
     /// are stroked.
     pub line_join: LineJoin,
+    /// The dash pattern used when stroking the line.
+    pub line_dash: LineDash<'a>,
 }
 
-impl Stroke {
+impl<'a> Stroke<'a> {
     /// Sets the color of the [`Stroke`].
-    pub fn with_color(self, color: Color) -> Stroke {
+    pub fn with_color(self, color: Color) -> Self {
         Stroke { color, ..self }
     }
 
     /// Sets the width of the [`Stroke`].
-    pub fn with_width(self, width: f32) -> Stroke {
+    pub fn with_width(self, width: f32) -> Self {
         Stroke { width, ..self }
     }
 
     /// Sets the [`LineCap`] of the [`Stroke`].
-    pub fn with_line_cap(self, line_cap: LineCap) -> Stroke {
+    pub fn with_line_cap(self, line_cap: LineCap) -> Self {
         Stroke { line_cap, ..self }
     }
 
     /// Sets the [`LineJoin`] of the [`Stroke`].
-    pub fn with_line_join(self, line_join: LineJoin) -> Stroke {
+    pub fn with_line_join(self, line_join: LineJoin) -> Self {
         Stroke { line_join, ..self }
     }
 }
 
-impl Default for Stroke {
-    fn default() -> Stroke {
+impl<'a> Default for Stroke<'a> {
+    fn default() -> Self {
         Stroke {
             color: Color::BLACK,
             width: 1.0,
             line_cap: LineCap::default(),
             line_join: LineJoin::default(),
+            line_dash: LineDash::default(),
         }
     }
 }
@@ -103,3 +106,13 @@ impl From<LineJoin> for lyon::tessellation::LineJoin {
         }
     }
 }
+
+/// The dash pattern used when stroking the line.
+#[derive(Debug, Clone, Copy, Default)]
+pub struct LineDash<'a> {
+    /// The alternating lengths of lines and gaps which describe the pattern.
+    pub segments: &'a [f32],
+
+    /// The offset of [`LineDash::segments`] to start the pattern.
+    pub offset: usize,
+}
diff --git a/graphics/src/widget/qr_code.rs b/graphics/src/widget/qr_code.rs
index 285b8622..907794b7 100644
--- a/graphics/src/widget/qr_code.rs
+++ b/graphics/src/widget/qr_code.rs
@@ -5,8 +5,7 @@ use crate::Backend;
 
 use iced_native::layout;
 use iced_native::{
-    Color, Element, Hasher, Layout, Length, Point, Rectangle, Size, Vector,
-    Widget,
+    Color, Element, Layout, Length, Point, Rectangle, Size, Vector, Widget,
 };
 use thiserror::Error;
 
@@ -74,12 +73,6 @@ where
         ))
     }
 
-    fn hash_layout(&self, state: &mut Hasher) {
-        use std::hash::Hash;
-
-        self.state.contents.hash(state);
-    }
-
     fn draw(
         &self,
         renderer: &mut Renderer<B>,