Use LayoutSVGResourceClipper::resourceBoundingBox() in ClipPathClipper

third_party/WebKit/Source/core/paint/ClipPathClipper.cpp

 // Copyright 2016 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 "core/paint/ClipPathClipper.h"
 
 #include "core/layout/svg/LayoutSVGResourceClipper.h"
 #include "core/style/ClipPathOperation.h"
 #include "platform/graphics/paint/ClipPathRecorder.h"
 
 namespace blink {
 
 ClipPathClipper::ClipPathClipper(
     GraphicsContext& context,
     const LayoutObject& layoutObject,
     const FloatRect& referenceBox,
-    const FloatRect& visualOverflowRect,
     const FloatPoint& origin)
     : m_resourceClipper(nullptr)
     , m_clipperState(SVGClipPainter::ClipperNotApplied)
     , m_layoutObject(layoutObject)
     , m_context(context)
 {
     DCHECK(layoutObject.styleRef().clipPath());
     ClipPathOperation* clipPathOperation = layoutObject.styleRef().clipPath();
     if (clipPathOperation->type() == ClipPathOperation::SHAPE) {
         ShapeClipPathOperation* shape = toShapeClipPathOperation(clipPathOperation);
-        if (shape->isValid())
-            m_clipPathRecorder.emplace(context, layoutObject, shape->path(referenceBox));
+        if (!shape->isValid())
+            return;
+        m_clipPathRecorder.emplace(context, layoutObject, shape->path(referenceBox));
     } else {
         DCHECK_EQ(clipPathOperation->type(), ClipPathOperation::REFERENCE);
         ReferenceClipPathOperation* referenceClipPathOperation = toReferenceClipPathOperation(clipPathOperation);
-        Document& document = layoutObject.document();
         // TODO(fs): It doesn't work with forward or external SVG references (https://bugs.webkit.org/show_bug.cgi?id=90405)
-        Element* element = document.getElementById(referenceClipPathOperation->fragment());
-        if (isSVGClipPathElement(element) && element->layoutObject()) {
-            m_resourceClipper = toLayoutSVGResourceClipper(toLayoutSVGResourceContainer(element->layoutObject()));
-            // When SVG applies the clip, and the coordinate system is "userspace on use", we must explicitly pass in
-            // the offset to have the clip paint in the correct location. When the coordinate system is
-            // "object bounding box" the offset should already be accounted for in the visualOverflowRect.
-            FloatPoint originTranslation = m_resourceClipper->clipPathUnits() == SVGUnitTypes::kSvgUnitTypeUserspaceonuse ?
-                origin : FloatPoint();
-            if (!SVGClipPainter(*m_resourceClipper).prepareEffect(layoutObject, referenceBox,
-                visualOverflowRect, originTranslation, context, m_clipperState)) {
-                // No need to "finish" the clipper if this failed.
-                m_resourceClipper = nullptr;
-            }
+        Element* element = layoutObject.document().getElementById(referenceClipPathOperation->fragment());
+        if (!isSVGClipPathElement(element) || !element->layoutObject())
+            return;
+        LayoutSVGResourceClipper* clipper = toLayoutSVGResourceClipper(toLayoutSVGResourceContainer(element->layoutObject()));
+        // Compute the (conservative) bounds of the clip-path.
+        FloatRect clipPathBounds = clipper->resourceBoundingBox(referenceBox);
+        // When SVG applies the clip, and the coordinate system is "userspace on use", we must explicitly pass in
+        // the offset to have the clip paint in the correct location. When the coordinate system is
+        // "object bounding box" the offset should already be accounted for in the reference box.
+        FloatPoint originTranslation;
+        if (clipper->clipPathUnits() == SVGUnitTypes::kSvgUnitTypeUserspaceonuse) {
+            clipPathBounds.moveBy(origin);
+            originTranslation = origin;
         }
+        if (!SVGClipPainter(*clipper).prepareEffect(layoutObject, referenceBox,
+            clipPathBounds, originTranslation, context, m_clipperState))
+            return;
+        m_resourceClipper = clipper;
     }
 }
 
 ClipPathClipper::~ClipPathClipper()
 {
     if (m_resourceClipper)
         SVGClipPainter(*m_resourceClipper).finishEffect(m_layoutObject, m_context, m_clipperState);
 }
 
 } // namespace blink