Unify content transformation calculations for SVG clip paths

Source/core/paint/SVGClipPainter.cpp

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 #include "core/paint/SVGClipPainter.h"
 
 #include "core/dom/ElementTraversal.h"
 #include "core/layout/svg/LayoutSVGResourceClipper.h"
 #include "core/layout/svg/SVGResources.h"
@@ skipping 31 matching lines @@
 {
     ASSERT(context);
     ASSERT(clipperState == ClipperNotApplied);
     ASSERT_WITH_SECURITY_IMPLICATION(!m_clip.needsLayout());
 
     if (paintInvalidationRect.isEmpty() || m_clip.hasCycle())
         return false;
 
     SVGClipExpansionCycleHelper inClipExpansionChange(m_clip);
 
-    AffineTransform animatedLocalTransform = toSVGClipPathElement(m_clip.element())->calculateAnimatedLocalTransform();
-    // When drawing a clip for non-SVG elements, the CTM does not include the zoom factor.
-    // In this case, we need to apply the zoom scale explicitly - but only for clips with
-    // userSpaceOnUse units (the zoom is accounted for objectBoundingBox-resolved lengths).
-    if (!target.isSVG() && m_clip.clipPathUnits() == SVGUnitTypes::SVG_UNIT_TYPE_USERSPACEONUSE) {
-        ASSERT(m_clip.style());
-        animatedLocalTransform.scale(m_clip.style()->effectiveZoom());
-    }
+    AffineTransform contentTransformation = m_clip.calculateContentTransformation(&target, targetBoundingBox);
 
     // First, try to apply the clip as a clipPath.
-    if (m_clip.tryPathOnlyClipping(target, context, animatedLocalTransform, targetBoundingBox)) {
+    if (m_clip.tryPathOnlyClipping(target, context, contentTransformation)) {
         clipperState = ClipperAppliedPath;
         return true;
     }
 
     // Fall back to masking.
     clipperState = ClipperAppliedMask;
 
     // Begin compositing the clip mask.
     CompositingRecorder::beginCompositing(*context, target, SkXfermode::kSrcOver_Mode, 1, &paintInvalidationRect);
     {
-        TransformRecorder recorder(*context, target, animatedLocalTransform);
-
         // clipPath can also be clipped by another clipPath.
         SVGResources* resources = SVGResourcesCache::cachedResourcesForLayoutObject(&m_clip);
         LayoutSVGResourceClipper* clipPathClipper = resources ? resources->clipper() : 0;
         ClipperState clipPathClipperState = ClipperNotApplied;
-        if (clipPathClipper && !SVGClipPainter(*clipPathClipper).applyClippingToContext(m_clip, targetBoundingBox, paintInvalidationRect, context, clipPathClipperState)) {
-            // End the clip mask's compositor.
-            CompositingRecorder::endCompositing(*context, target);
-            return false;
+        if (clipPathClipper) {
+            FloatRect contentBoundingBox = contentTransformation.mapRect(targetBoundingBox);
+            if (!SVGClipPainter(*clipPathClipper).applyClippingToContext(m_clip, contentBoundingBox, paintInvalidationRect, context, clipPathClipperState)) {
+                // End the clip mask's compositor.
+                CompositingRecorder::endCompositing(*context, target);
+                return false;
+            }
         }
 
-        drawClipMaskContent(context, target, targetBoundingBox);
+        drawClipMaskContent(context, target, contentTransformation);
 
         if (clipPathClipper)
             SVGClipPainter(*clipPathClipper).postApplyStatefulResource(m_clip, context, clipPathClipperState);
     }
 
     // Masked content layer start.
     CompositingRecorder::beginCompositing(*context, target, SkXfermode::kSrcIn_Mode, 1, &paintInvalidationRect);
 
     return true;
 }
@@ skipping 17 matching lines @@
         CompositingRecorder::endCompositing(*context, target);
 
         // Transfer clip mask -> bg (SrcOver)
         CompositingRecorder::endCompositing(*context, target);
         break;
     default:
         ASSERT_NOT_REACHED();
     }
 }
 
-void SVGClipPainter::drawClipMaskContent(GraphicsContext* context, const LayoutObject& layoutObject, const FloatRect& targetBoundingBox)
+void SVGClipPainter::drawClipMaskContent(GraphicsContext* context, const LayoutObject& layoutObject, const AffineTransform& contentTransformation)
 {
     ASSERT(context);
 
-    AffineTransform contentTransformation;
-    RefPtr<const SkPicture> clipContentPicture = m_clip.createContentPicture(contentTransformation, targetBoundingBox, context);
+    RefPtr<const SkPicture> clipContentPicture = m_clip.createContentPicture(contentTransformation, context);
 
     TransformRecorder recorder(*context, layoutObject, contentTransformation);
     if (RuntimeEnabledFeatures::slimmingPaintEnabled()) {
         ASSERT(context->displayItemList());
         if (context->displayItemList()->displayItemConstructionIsDisabled())
             return;
         context->displayItemList()->add(DrawingDisplayItem::create(layoutObject, DisplayItem::SVGClip, clipContentPicture));
     } else {
         DrawingDisplayItem clipPicture(layoutObject, DisplayItem::SVGClip, clipContentPicture);
         clipPicture.replay(*context);
     }
 }
 
 }