Canvas: add clipping path support.

components/canvas/canvas_msg.rs

@@ -24,8 +24,9 @@ pub enum Canvas2dMsg {
     DrawImageSelf(Size2D<f64>, Rect<f64>, Rect<f64>, bool),
     BeginPath,
     BezierCurveTo(Point2D<f32>, Point2D<f32>, Point2D<f32>),
-    ClosePath,
     ClearRect(Rect<f32>),
+    Clip,
+    ClosePath,
     Fill,
     FillRect(Rect<f32>),
     GetImageData(Rect<f64>, Size2D<f64>, Sender<Vec<u8>>),

components/canvas/canvas_paint_task.rs

@@ -212,6 +212,7 @@ impl<'a> CanvasPaintTask<'a> {
                             Canvas2dMsg::ClosePath => painter.close_path(),
                             Canvas2dMsg::Fill => painter.fill(),
                             Canvas2dMsg::Stroke => painter.stroke(),
+                            Canvas2dMsg::Clip => painter.clip(),
                             Canvas2dMsg::DrawImage(imagedata, image_size, dest_rect, source_rect, smoothing_enabled) => {
                                 painter.draw_image(imagedata, image_size, dest_rect, source_rect, smoothing_enabled)
                             }
@@ -271,6 +272,7 @@ impl<'a> CanvasPaintTask<'a> {
         if let Some(state) = self.saved_states.pop() {
             mem::replace(&mut self.state, state);
             self.drawtarget.set_transform(&self.state.transform);
+            self.drawtarget.pop_clip();
         }
     }
 
@@ -325,6 +327,10 @@ impl<'a> CanvasPaintTask<'a> {
         };
     }
 
+    fn clip(&self) {
+        self.drawtarget.push_clip(&self.path_builder.finish());
+    }
+
     fn draw_image(&self, image_data: Vec<u8>, image_size: Size2D<f64>,
                   dest_rect: Rect<f64>, source_rect: Rect<f64>, smoothing_enabled: bool) {
         // We round up the floating pixel values to draw the pixels

components/script/dom/canvasrenderingcontext2d.rs

@@ -454,6 +454,7 @@ impl<'a> CanvasRenderingContext2DMethods for JSRef<'a, CanvasRenderingContext2D>
 
     // https://html.spec.whatwg.org/multipage/#dom-context-2d-fill
     fn Fill(self, _: CanvasWindingRule) {
+        // TODO: Process winding rule
         self.renderer.send(CanvasMsg::Canvas2d(Canvas2dMsg::Fill)).unwrap();
     }
 
@@ -462,6 +463,12 @@ impl<'a> CanvasRenderingContext2DMethods for JSRef<'a, CanvasRenderingContext2D>
         self.renderer.send(CanvasMsg::Canvas2d(Canvas2dMsg::Stroke)).unwrap();
     }
 
+    // https://html.spec.whatwg.org/multipage/#dom-context-2d-clip
+    fn Clip(self, _: CanvasWindingRule) {
+        // TODO: Process winding rule
+        self.renderer.send(CanvasMsg::Canvas2d(Canvas2dMsg::Clip)).unwrap();
+    }
+
     // https://html.spec.whatwg.org/multipage/#dom-context-2d-drawimage
     fn DrawImage(self, image: HTMLImageElementOrHTMLCanvasElementOrCanvasRenderingContext2D,
                  dx: f64, dy: f64) -> Fallible<()> {

components/script/dom/webidls/CanvasRenderingContext2D.webidl

@@ -90,7 +90,7 @@ interface CanvasRenderingContext2D {
   //boolean drawCustomFocusRing(Path2D path, Element element);
   //void scrollPathIntoView();
   //void scrollPathIntoView(Path2D path);
-  //void clip(optional CanvasWindingRule fillRule = "nonzero");
+  void clip(optional CanvasWindingRule fillRule = "nonzero");
   //void clip(Path2D path, optional CanvasWindingRule fillRule = "nonzero");
   //void resetClip();
   //boolean isPointInPath(unrestricted double x, unrestricted double y, optional CanvasWindingRule fillRule = "nonzero");

tests/wpt/metadata/html/dom/interfaces.html.ini

@@ -6924,9 +6924,6 @@
   [CanvasRenderingContext2D interface: operation clip(CanvasFillRule)]
     expected: FAIL
 
-  [CanvasRenderingContext2D interface: operation clip(Path2D,CanvasFillRule)]
-    expected: FAIL
-
   [CanvasRenderingContext2D interface: operation resetClip()]
     expected: FAIL
 
@@ -7086,15 +7083,6 @@
   [CanvasRenderingContext2D interface: calling scrollPathIntoView(Path2D) on document.createElement("canvas").getContext("2d") with too few arguments must throw TypeError]
     expected: FAIL
 
-  [CanvasRenderingContext2D interface: document.createElement("canvas").getContext("2d") must inherit property "clip" with the proper type (39)]
-    expected: FAIL
-
-  [CanvasRenderingContext2D interface: calling clip(CanvasFillRule) on document.createElement("canvas").getContext("2d") with too few arguments must throw TypeError]
-    expected: FAIL
-
-  [CanvasRenderingContext2D interface: document.createElement("canvas").getContext("2d") must inherit property "clip" with the proper type (40)]
-    expected: FAIL
-
   [CanvasRenderingContext2D interface: calling clip(Path2D,CanvasFillRule) on document.createElement("canvas").getContext("2d") with too few arguments must throw TypeError]
     expected: FAIL