Bug 1246762 - Add support for inset() in clip-path ; r=dholbert

MozReview-Commit-ID: 9AhkTu9gVVm

--HG--
extra : rebase_source : d9ee4f4b4f3654203d2cd1c0f915eea04374d5d0

layout/svg/nsCSSClipPathInstance.cpp

@@ -101,7 +101,7 @@ nsCSSClipPathInstance::CreateClipPath(DrawTarget* aDrawTarget)
     case StyleBasicShapeType::Polygon:
       return CreateClipPathPolygon(aDrawTarget, r);
     case StyleBasicShapeType::Inset:
-      // XXXkrit support all basic shapes
+      return CreateClipPathInset(aDrawTarget, r);
       break;
     default:
       MOZ_MAKE_COMPILER_ASSUME_IS_UNREACHABLE("Unexpected shape type");
@@ -239,3 +239,41 @@ nsCSSClipPathInstance::CreateClipPathPolygon(DrawTarget* aDrawTarget,
   builder->Close();
   return builder->Finish();
 }
+
+already_AddRefed<Path>
+nsCSSClipPathInstance::CreateClipPathInset(DrawTarget* aDrawTarget,
+                                           const nsRect& aRefBox)
+{
+  StyleBasicShape* basicShape = mClipPathStyle.GetBasicShape();
+  const nsTArray<nsStyleCoord>& coords = basicShape->Coordinates();
+  MOZ_ASSERT(coords.Length() == 4, "wrong number of arguments");
+
+  RefPtr<PathBuilder> builder = aDrawTarget->CreatePathBuilder();
+
+  nscoord appUnitsPerDevPixel =
+    mTargetFrame->PresContext()->AppUnitsPerDevPixel();
+
+  nsMargin inset(nsRuleNode::ComputeCoordPercentCalc(coords[0], aRefBox.height),
+                 nsRuleNode::ComputeCoordPercentCalc(coords[1], aRefBox.width),
+                 nsRuleNode::ComputeCoordPercentCalc(coords[2], aRefBox.height),
+                 nsRuleNode::ComputeCoordPercentCalc(coords[3], aRefBox.width));
+
+  nsRect insetRect(aRefBox);
+  insetRect.Deflate(inset);
+  const Rect insetRectPixels = NSRectToRect(insetRect, appUnitsPerDevPixel);
+  const nsStyleCorners& radius = basicShape->GetRadius();
+
+  nscoord appUnitsRadii[8];
+
+  if (nsIFrame::ComputeBorderRadii(radius, insetRect.Size(), aRefBox.Size(),
+                                   Sides(), appUnitsRadii)) {
+    RectCornerRadii corners;
+    nsCSSRendering::ComputePixelRadii(appUnitsRadii,
+                                      appUnitsPerDevPixel, &corners);
+
+    AppendRoundedRectToPath(builder, insetRectPixels, corners, true);
+  } else {
+    AppendRectToPath(builder, insetRectPixels, true);
+  }
+  return builder->Finish();
+}

layout/svg/nsCSSClipPathInstance.h

@@ -45,6 +45,8 @@ private:
   already_AddRefed<Path> CreateClipPathPolygon(DrawTarget* aDrawTarget,
                                                const nsRect& aRefBox);
 
+  already_AddRefed<Path> CreateClipPathInset(DrawTarget* aDrawTarget,
+                                             const nsRect& aRefBox);
   /**
    * The frame for the element that is currently being clipped.
    */