Merge WebKit at r63173 : Initial merge by git.

Change-Id: Ife5af0c7c6261fbbc8ae6bc08c390efa9ef10b44

1 files changed, 14 insertions, 13 deletions

diff --git a/WebCore/rendering/RenderSVGResourceGradient.cpp b/WebCore/rendering/RenderSVGResourceGradient.cpp
index 7ea70d2..74f5b13 100644
--- a/WebCore/rendering/RenderSVGResourceGradient.cpp
+++ b/WebCore/rendering/RenderSVGResourceGradient.cpp
@@ -73,17 +73,12 @@ void RenderSVGResourceGradient::invalidateClient(RenderObject* object)
 }
 
 #if PLATFORM(CG)
-static inline AffineTransform absoluteTransformForRenderer(const RenderObject* object)
+static inline AffineTransform absoluteTransformFromContext(GraphicsContext* context)
 {
-    AffineTransform absoluteTransform;
-
-    const RenderObject* currentObject = object;
-    while (currentObject) {
-        absoluteTransform = currentObject->localToParentTransform() * absoluteTransform;
-        currentObject = currentObject->parent();
-    }
-
-    return absoluteTransform;
+    // Extract current transformation matrix used in the original context. Note that this coordinate
+    // system is flipped compared to SVGs internal coordinate system, done in WebKit level. Fix
+    // this transformation by flipping the y component.
+    return context->getCTM() * AffineTransform().flipY();
 }
 
 static inline bool createMaskAndSwapContextForTextGradient(GraphicsContext*& context,
@@ -93,7 +88,7 @@ static inline bool createMaskAndSwapContextForTextGradient(GraphicsContext*& con
 {
     const RenderObject* textRootBlock = SVGRenderSupport::findTextRootObject(object);
 
-    AffineTransform transform = absoluteTransformForRenderer(textRootBlock);
+    AffineTransform transform(absoluteTransformFromContext(context));
     FloatRect maskAbsoluteBoundingBox = transform.mapRect(textRootBlock->repaintRectInLocalCoordinates());
 
     IntRect maskImageRect = enclosingIntRect(maskAbsoluteBoundingBox);
@@ -111,7 +106,7 @@ static inline bool createMaskAndSwapContextForTextGradient(GraphicsContext*& con
     maskImageContext->translate(-maskAbsoluteBoundingBox.x(), -maskAbsoluteBoundingBox.y());
     maskImageContext->concatCTM(transform);
 
-    imageBuffer.set(maskImage.release());
+    imageBuffer = maskImage.release();
     savedContext = context;
     context = maskImageContext;
 
@@ -124,7 +119,13 @@ static inline AffineTransform clipToTextMask(GraphicsContext* context,
                                              GradientData* gradientData)
 {
     const RenderObject* textRootBlock = SVGRenderSupport::findTextRootObject(object);
-    context->clipToImageBuffer(textRootBlock->repaintRectInLocalCoordinates(), imageBuffer.get());
+
+    // The mask image has been created in the device coordinate space, as the image should not be scaled.
+    // So the actual masking process has to be done in the device coordinate space as well.
+    AffineTransform transform(absoluteTransformFromContext(context));
+    context->concatCTM(transform.inverse());
+    context->clipToImageBuffer(transform.mapRect(textRootBlock->repaintRectInLocalCoordinates()), imageBuffer.get());
+    context->concatCTM(transform);
 
     AffineTransform matrix;
     if (gradientData->boundingBoxMode) {