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* Copyright (C) 2003, 2009, 2012 Apple Inc. All rights reserved.
* Copyright (C) 2013 Intel Corporation. All rights reserved.
* Portions are Copyright (C) 1998 Netscape Communications Corporation.
* Other contributors:
* Robert O'Callahan <>
* David Baron <>
* Christian Biesinger <>
* Randall Jesup <>
* Roland Mainz <>
* Josh Soref <>
* Boris Zbarsky <>
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* Lesser General Public License for more details.
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
* Alternatively, the contents of this file may be used under the terms
* of either the Mozilla Public License Version 1.1, found at
* (the "MPL") or the GNU General Public
* License Version 2.0, found at
* (the "GPL"), in which case the provisions of the MPL or the GPL are
* applicable instead of those above. If you wish to allow use of your
* version of this file only under the terms of one of those two
* licenses (the MPL or the GPL) and not to allow others to use your
* version of this file under the LGPL, indicate your decision by
* deletingthe provisions above and replace them with the notice and
* other provisions required by the MPL or the GPL, as the case may be.
* If you do not delete the provisions above, a recipient may use your
* version of this file under any of the LGPL, the MPL or the GPL.
#ifndef RenderLayerClipper_h
#define RenderLayerClipper_h
#include "core/rendering/ClipRectsCache.h"
#include "core/rendering/RenderBox.h"
namespace blink {
class RenderLayer;
enum ShouldRespectOverflowClip {
class ClipRectsContext {
ClipRectsContext(const RenderLayer* root, ClipRectsCacheSlot slot, OverlayScrollbarSizeRelevancy relevancy = IgnoreOverlayScrollbarSize, const LayoutSize& accumulation = LayoutSize())
: rootLayer(root)
, scrollbarRelevancy(relevancy)
, cacheSlot(slot)
, subPixelAccumulation(accumulation)
, respectOverflowClip(slot == PaintingClipRectsIgnoringOverflowClip ? IgnoreOverflowClip : RespectOverflowClip)
void setIgnoreOverflowClip()
ASSERT(!usesCache() || cacheSlot == PaintingClipRects);
ASSERT(respectOverflowClip == RespectOverflowClip);
if (usesCache())
cacheSlot = PaintingClipRectsIgnoringOverflowClip;
respectOverflowClip = IgnoreOverflowClip;
bool usesCache() const
return cacheSlot != UncachedClipRects;
const RenderLayer* const rootLayer;
const OverlayScrollbarSizeRelevancy scrollbarRelevancy;
friend class RenderLayerClipper;
ClipRectsCacheSlot cacheSlot;
LayoutSize subPixelAccumulation;
ShouldRespectOverflowClip respectOverflowClip;
class RenderLayerClipper {
explicit RenderLayerClipper(RenderLayerModelObject&);
void clearClipRectsIncludingDescendants();
void clearClipRectsIncludingDescendants(ClipRectsCacheSlot);
LayoutRect childrenClipRect() const; // Returns the foreground clip rect of the layer in the document's coordinate space.
LayoutRect localClipRect() const; // Returns the background clip rect of the layer in the local coordinate space.
ClipRects* getClipRects(const ClipRectsContext&) const;
ClipRect backgroundClipRect(const ClipRectsContext&) const;
// This method figures out our layerBounds in coordinates relative to
// |rootLayer|. It also computes our background and foreground clip rects
// for painting/event handling.
// Pass offsetFromRoot if known.
void calculateRects(const ClipRectsContext&, const LayoutRect& paintDirtyRect, LayoutRect& layerBounds,
ClipRect& backgroundRect, ClipRect& foregroundRect, ClipRect& outlineRect, const LayoutPoint* offsetFromRoot = 0) const;
void calculateClipRects(const ClipRectsContext&, ClipRects&) const;
ClipRects* clipRectsIfCached(const ClipRectsContext&) const;
ClipRects* storeClipRectsInCache(const ClipRectsContext&, ClipRects* parentClipRects, const ClipRects&) const;
// cachedClipRects looks buggy: It doesn't check whether context.rootLayer and entry.root match.
// FIXME: Move callers to clipRectsIfCached, which does the proper checks.
ClipRects* cachedClipRects(const ClipRectsContext& context) const
return m_cache ? m_cache->get(context.cacheSlot).clipRects.get() : 0;
void getOrCalculateClipRects(const ClipRectsContext&, ClipRects&) const;
RenderLayer* clippingRootForPainting() const;
ClipRectsCache& cache() const
if (!m_cache)
m_cache = adoptPtr(new ClipRectsCache);
return *m_cache;
// FIXME: Could this be a RenderBox?
RenderLayerModelObject& m_renderer;
mutable OwnPtr<ClipRectsCache> m_cache;
} // namespace blink
#endif // RenderLayerClipper_h