Support control clipping for PaintLayers.

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

 /*
  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011, 2012 Apple Inc. All rights
  * reserved.
  *
  * Portions are Copyright (C) 1998 Netscape Communications Corporation.
  *
  * Other contributors:
  *   Robert O'Callahan <roc+@cs.cmu.edu>
  *   David Baron <dbaron@fas.harvard.edu>
  *   Christian Biesinger <cbiesinger@web.de>
@@ skipping 56 matching lines @@
     clipRects.setPosClipRect(clipRects.overflowClipRect());
   } else if (position == AbsolutePosition) {
     clipRects.setOverflowClipRect(clipRects.posClipRect());
   }
 }
 
 static void applyClipRects(const ClipRectsContext& context,
                            const LayoutBoxModelObject& layoutObject,
                            LayoutPoint offset,
                            ClipRects& clipRects) {
-  DCHECK(layoutObject.hasClipRelatedProperty() ||
-         (layoutObject.isSVGRoot() &&
-          toLayoutSVGRoot(&layoutObject)->shouldApplyViewportClip()));
-  LayoutView* view = layoutObject.view();
+  DCHECK(layoutObject.isBox());
+  const LayoutBox& box = *toLayoutBox(&layoutObject);
+
+  DCHECK(box.hasClipRelatedProperty() || box.hasControlClip() ||
+         (box.isSVGRoot() && toLayoutSVGRoot(&box)->shouldApplyViewportClip()));
+  LayoutView* view = box.view();
   DCHECK(view);
   if (clipRects.fixed() && context.rootLayer->layoutObject() == view)
     offset -= LayoutSize(view->frameView()->getScrollOffset());
-  if (layoutObject.hasOverflowClip() ||
-      (layoutObject.isSVGRoot() &&
-       toLayoutSVGRoot(&layoutObject)->shouldApplyViewportClip()) ||
-      (layoutObject.styleRef().containsPaint() && layoutObject.isBox())) {
+
+  if (box.hasOverflowClip() ||
+      (box.isSVGRoot() && toLayoutSVGRoot(&box)->shouldApplyViewportClip()) ||
+      box.styleRef().containsPaint() || box.hasControlClip()) {
     ClipRect newOverflowClip =
-        toLayoutBox(layoutObject)
-            .overflowClipRect(offset, context.overlayScrollbarClipBehavior);
-    newOverflowClip.setHasRadius(layoutObject.styleRef().hasBorderRadius());
+        box.overflowClipRect(offset, context.overlayScrollbarClipBehavior);
+    newOverflowClip.setHasRadius(box.styleRef().hasBorderRadius());
     clipRects.setOverflowClipRect(
         intersection(newOverflowClip, clipRects.overflowClipRect()));
-    if (layoutObject.isPositioned())
+    if (box.isPositioned())
       clipRects.setPosClipRect(
           intersection(newOverflowClip, clipRects.posClipRect()));
-    if (layoutObject.isLayoutView() ||
-        layoutObject.hasTransformRelatedProperty())
+    if (box.isLayoutView() || box.hasTransformRelatedProperty())
       clipRects.setFixedClipRect(
           intersection(newOverflowClip, clipRects.fixedClipRect()));
-    if (layoutObject.styleRef().containsPaint()) {
+    if (box.styleRef().containsPaint()) {
       clipRects.setPosClipRect(
           intersection(newOverflowClip, clipRects.posClipRect()));
       clipRects.setFixedClipRect(
           intersection(newOverflowClip, clipRects.fixedClipRect()));
     }
   }
-  if (layoutObject.hasClip()) {
-    LayoutRect newClip = toLayoutBox(layoutObject).clipRect(offset);
+  if (box.hasClip()) {
+    LayoutRect newClip = box.clipRect(offset);
     clipRects.setPosClipRect(
         intersection(newClip, clipRects.posClipRect()).setIsClippedByClipCss());
     clipRects.setOverflowClipRect(
         intersection(newClip, clipRects.overflowClipRect())
             .setIsClippedByClipCss());
     clipRects.setFixedClipRect(intersection(newClip, clipRects.fixedClipRect())
                                    .setIsClippedByClipCss());
   }
 }
 
@@ skipping 417 matching lines @@
 void PaintLayerClipper::getOrCalculateClipRects(const ClipRectsContext& context,
                                                 ClipRects& clipRects) const {
   if (context.usesCache())
     clipRects = getClipRects(context);
   else
     calculateClipRects(context, clipRects);
 }
 
 bool PaintLayerClipper::shouldClipOverflow(
     const ClipRectsContext& context) const {
-  LayoutObject* layoutObject = m_layer.layoutObject();
-  return (layoutObject->hasOverflowClip() ||
-          layoutObject->styleRef().containsPaint() ||
-          (layoutObject->isSVGRoot() &&
-           toLayoutSVGRoot(layoutObject)->shouldApplyViewportClip())) &&
-         shouldRespectOverflowClip(context);
+  if (!m_layer.layoutObject()->isBox())
+    return false;
+  const LayoutBox& box = *toLayoutBox(m_layer.layoutObject());
+
+  if (!shouldRespectOverflowClip(context))
+    return false;
+
+  return box.hasOverflowClip() || box.styleRef().containsPaint() ||
+         box.hasControlClip() ||
+         (box.isSVGRoot() && toLayoutSVGRoot(&box)->shouldApplyViewportClip());
 }
 
 bool PaintLayerClipper::shouldRespectOverflowClip(
     const ClipRectsContext& context) const {
   if (&m_layer != context.rootLayer)
     return true;
 
   if (context.respectOverflowClip == IgnoreOverflowClip)
     return false;
 
@@ skipping 10 matching lines @@
     const LayoutSize& subpixelAccumulation) const {
   DCHECK(!m_geometryMapper);
   ClipRectsContext context(rootLayer, PaintingClipRects,
                            IgnoreOverlayScrollbarSize, subpixelAccumulation);
   if (respectOverflowClip == IgnoreOverflowClip)
     context.setIgnoreOverflowClip();
   return getClipRects(context);
 }
 
 }  // namespace blink