Bug 1864039 - clip-path path reference box is incorrect with stroke r…

…=boris

Differential Revision: https://phabricator.services.mozilla.com/D193643

dom/svg/SVGPathData.cpp

@@ -582,7 +582,8 @@ already_AddRefed<Path> SVGPathData::BuildPathForMeasuring(
 /* static */
 already_AddRefed<Path> SVGPathData::BuildPath(
     Span<const StylePathCommand> aPath, PathBuilder* aBuilder,
-    StyleStrokeLinecap aStrokeLineCap, Float aStrokeWidth, float aZoomFactor) {
+    StyleStrokeLinecap aStrokeLineCap, Float aStrokeWidth, const Point& aOffset,
+    float aZoomFactor) {
   if (aPath.IsEmpty() || !aPath[0].IsMoveTo()) {
     return nullptr;  // paths without an initial moveto are invalid
   }
@@ -599,8 +600,8 @@ already_AddRefed<Path> SVGPathData::BuildPath(
   Point cp1, cp2;    // previous bezier's control points
   Point tcp1, tcp2;  // temporaries
 
-  auto scale = [aZoomFactor](const Point& p) {
-    return Point(p.x * aZoomFactor, p.y * aZoomFactor);
+  auto scale = [aOffset, aZoomFactor](const Point& p) {
+    return Point(p.x * aZoomFactor, p.y * aZoomFactor) + aOffset;
   };
 
   // Regarding cp1 and cp2: If the previous segment was a cubic bezier curve,

dom/svg/SVGPathData.h

@@ -194,11 +194,10 @@ class SVGPathData {
    * which is generated by cbindgen from Rust (see ServoStyleConsts.h).
    * Basically, this is a variant of the above BuildPath() functions.
    */
-  static already_AddRefed<Path> BuildPath(Span<const StylePathCommand> aPath,
-                                          PathBuilder* aBuilder,
-                                          StyleStrokeLinecap aStrokeLineCap,
-                                          Float aStrokeWidth,
-                                          float aZoomFactor = 1.0);
+  static already_AddRefed<Path> BuildPath(
+      Span<const StylePathCommand> aPath, PathBuilder* aBuilder,
+      StyleStrokeLinecap aStrokeLineCap, Float aStrokeWidth,
+      const gfx::Point& aOffset = gfx::Point(), float aZoomFactor = 1.0);
 
   const_iterator begin() const { return mData.Elements(); }
   const_iterator end() const { return mData.Elements() + mData.Length(); }

layout/svg/CSSClipPathInstance.cpp

@@ -86,10 +86,6 @@ Maybe<Rect> CSSClipPathInstance::GetBoundingRectForBasicShapeOrPathClip(
 
 already_AddRefed<Path> CSSClipPathInstance::CreateClipPath(
     DrawTarget* aDrawTarget, const gfxMatrix& aTransform) {
-  if (mClipPathStyle.IsShape() && mClipPathStyle.AsShape()._0->IsPath()) {
-    return CreateClipPathPath(aDrawTarget);
-  }
-
   nscoord appUnitsPerDevPixel =
       mTargetFrame->PresContext()->AppUnitsPerDevPixel();
 
@@ -125,6 +121,8 @@ already_AddRefed<Path> CSSClipPathInstance::CreateClipPath(
       return CreateClipPathPolygon(aDrawTarget, r);
     case StyleBasicShape::Tag::Rect:
       return CreateClipPathInset(aDrawTarget, r);
+    case StyleBasicShape::Tag::Path:
+      return CreateClipPathPath(aDrawTarget, r);
     default:
       MOZ_MAKE_COMPILER_ASSUME_IS_UNREACHABLE("Unexpected shape type");
   }
@@ -176,16 +174,19 @@ already_AddRefed<Path> CSSClipPathInstance::CreateClipPathInset(
 }
 
 already_AddRefed<Path> CSSClipPathInstance::CreateClipPathPath(
-    DrawTarget* aDrawTarget) {
+    DrawTarget* aDrawTarget, const nsRect& aRefBox) {
   const auto& path = mClipPathStyle.AsShape()._0->AsPath();
 
   RefPtr<PathBuilder> builder = aDrawTarget->CreatePathBuilder(
       path.fill == StyleFillRule::Nonzero ? FillRule::FILL_WINDING
                                           : FillRule::FILL_EVEN_ODD);
-  float scale = float(AppUnitsPerCSSPixel()) /
-                mTargetFrame->PresContext()->AppUnitsPerDevPixel();
+  nscoord appUnitsPerDevPixel =
+      mTargetFrame->PresContext()->AppUnitsPerDevPixel();
+  float scale = float(AppUnitsPerCSSPixel()) / appUnitsPerDevPixel;
+  Point offset = Point(aRefBox.x, aRefBox.y) / appUnitsPerDevPixel;
+
   return SVGPathData::BuildPath(path.path._0.AsSpan(), builder,
-                                StyleStrokeLinecap::Butt, 0.0, scale);
+                                StyleStrokeLinecap::Butt, 0.0, offset, scale);
 }
 
 }  // namespace mozilla

layout/svg/CSSClipPathInstance.h

@@ -55,7 +55,8 @@ class MOZ_STACK_CLASS CSSClipPathInstance {
   already_AddRefed<Path> CreateClipPathInset(DrawTarget* aDrawTarget,
                                              const nsRect& aRefBox);
 
-  already_AddRefed<Path> CreateClipPathPath(DrawTarget* aDrawTarget);
+  already_AddRefed<Path> CreateClipPathPath(DrawTarget* aDrawTarget,
+                                            const nsRect& aRefBox);
 
   /**
    * The frame for the element that is currently being clipped.