canvas: Move current_default_path to script CanvasState (#38114)

This PR moves current path handling from canvas paint thread to script's
`CanvasState`. Because we used manual impl for arcto and some prechecks
for early fail before sending IPC we also needed to fix some bugs in
Path impl.

Testing: Existing WPT tests
work towards #38022
try run: https://github.com/sagudev/servo/actions/runs/16316090028

Signed-off-by: sagudev <16504129+sagudev@users.noreply.github.com>

components/shared/canvas/canvas.rs

@@ -10,6 +10,7 @@ use euclid::approxeq::ApproxEq;
 use euclid::default::{Point2D, Rect, Size2D, Transform2D};
 use ipc_channel::ipc::IpcSender;
 use kurbo::{Affine, BezPath, ParamCurveNearest as _, PathEl, Point, Shape, Triangle};
+use malloc_size_of::MallocSizeOf;
 use malloc_size_of_derive::MallocSizeOf;
 use pixels::IpcSnapshot;
 use serde::{Deserialize, Serialize};
@@ -20,6 +21,12 @@ use style::properties::style_structs::Font as FontStyleStruct;
 #[derive(Clone, Debug, Default, Deserialize, Serialize)]
 pub struct Path(pub BezPath);
 
+impl MallocSizeOf for Path {
+    fn size_of(&self, _ops: &mut malloc_size_of::MallocSizeOfOps) -> usize {
+        std::mem::size_of_val(self.0.elements())
+    }
+}
+
 pub struct IndexSizeError;
 
 impl Path {
@@ -146,7 +153,7 @@ impl Path {
         self.ensure_there_is_a_subpath(x1, y1);
 
         // Step 3. If either radius is negative, then throw an "IndexSizeError" DOMException.
-        if radius.is_sign_negative() {
+        if radius < 0.0 {
             return Err(IndexSizeError);
         }
 
@@ -166,7 +173,7 @@ impl Path {
         // all lie on a single straight line, then add the point (x1, y1) to the subpath,
         // and connect that point to the previous point (x0, y0) by a straight line.
         let direction = Triangle::from_coords((x0, y0), (x1, y1), (x2, y2)).area();
-        if direction == 0.0 {
+        if direction.approx_eq(&0.0) {
             self.0.line_to((x1, y1));
             return Ok(());
         }
@@ -209,7 +216,7 @@ impl Path {
         let angle_start = (tp1.y - cy).atan2(tp1.x - cx);
         let angle_end = (tp2.y - cy).atan2(tp2.x - cx);
 
-        self.0.line_to((tp1.x, tp2.x));
+        self.0.line_to((tp1.x, tp1.y));
 
         self.arc(cx, cy, radius, angle_start, angle_end, anticlockwise)
     }
@@ -280,7 +287,7 @@ impl Path {
         }
 
         // Step 2. If either radiusX or radiusY are negative, then throw an "IndexSizeError" DOMException.
-        if radius_x.is_sign_negative() || radius_y.is_sign_negative() {
+        if radius_x < 0.0 || radius_y < 0.0 {
             return Err(IndexSizeError);
         }
 
@@ -419,34 +426,20 @@ pub enum CanvasMsg {
 
 #[derive(Debug, Deserialize, Serialize)]
 pub enum Canvas2dMsg {
-    Arc(Point2D<f32>, f32, f32, f32, bool),
-    ArcTo(Point2D<f32>, Point2D<f32>, f32),
     DrawImage(IpcSnapshot, Rect<f64>, Rect<f64>, bool),
     DrawEmptyImage(Size2D<u32>, Rect<f64>, Rect<f64>),
     DrawImageInOther(CanvasId, Size2D<u32>, Rect<f64>, Rect<f64>, bool),
-    BeginPath,
-    BezierCurveTo(Point2D<f32>, Point2D<f32>, Point2D<f32>),
     ClearRect(Rect<f32>),
-    Clip,
     ClipPath(Path),
-    ClosePath,
-    Ellipse(Point2D<f32>, f32, f32, f32, f32, f32, bool),
-    Fill(FillOrStrokeStyle),
     FillPath(FillOrStrokeStyle, Path),
     FillText(String, f64, f64, Option<f64>, FillOrStrokeStyle, bool),
     FillRect(Rect<f32>, FillOrStrokeStyle),
     GetImageData(Rect<u32>, Size2D<u32>, IpcSender<IpcSnapshot>),
-    IsPointInCurrentPath(f64, f64, FillRule, IpcSender<bool>),
-    LineTo(Point2D<f32>),
-    MoveTo(Point2D<f32>),
     MeasureText(String, IpcSender<TextMetrics>),
     PutImageData(Rect<u32>, IpcSnapshot),
-    QuadraticCurveTo(Point2D<f32>, Point2D<f32>),
-    Rect(Rect<f32>),
     RestoreContext,
     SaveContext,
     StrokeRect(Rect<f32>, FillOrStrokeStyle),
-    Stroke(FillOrStrokeStyle),
     StrokePath(FillOrStrokeStyle, Path),
     SetLineWidth(f32),
     SetLineCap(LineCapStyle),