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      1 /*
      2  * Copyright (C) 1999 Lars Knoll (knoll (at) kde.org)
      3  *           (C) 1999 Antti Koivisto (koivisto (at) kde.org)
      4  * Copyright (C) 2003, 2006, 2007, 2009 Apple Inc. All rights reserved.
      5  * Copyright (C) 2010, 2012 Google Inc. All rights reserved.
      6  *
      7  * This library is free software; you can redistribute it and/or
      8  * modify it under the terms of the GNU Library General Public
      9  * License as published by the Free Software Foundation; either
     10  * version 2 of the License, or (at your option) any later version.
     11  *
     12  * This library is distributed in the hope that it will be useful,
     13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
     14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     15  * Library General Public License for more details.
     16  *
     17  * You should have received a copy of the GNU Library General Public License
     18  * along with this library; see the file COPYING.LIB.  If not, write to
     19  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
     20  * Boston, MA 02110-1301, USA.
     21  */
     22 
     23 #ifndef RenderLayerModelObject_h
     24 #define RenderLayerModelObject_h
     25 
     26 #include "core/rendering/compositing/CompositedLayerMappingPtr.h"
     27 #include "core/rendering/RenderObject.h"
     28 
     29 namespace WebCore {
     30 
     31 class RenderLayer;
     32 class CompositedLayerMapping;
     33 class ScrollableArea;
     34 
     35 enum LayerType {
     36     NoLayer,
     37     NormalLayer,
     38     // A forced or overflow clip layer is required for bookkeeping purposes,
     39     // but does not force a layer to be self painting.
     40     OverflowClipLayer,
     41     ForcedLayer
     42 };
     43 
     44 class RenderLayerModelObject : public RenderObject {
     45 public:
     46     explicit RenderLayerModelObject(ContainerNode*);
     47     virtual ~RenderLayerModelObject();
     48 
     49     // This is the only way layers should ever be destroyed.
     50     void destroyLayer();
     51 
     52     bool hasSelfPaintingLayer() const;
     53     RenderLayer* layer() const { return m_layer.get(); }
     54     ScrollableArea* scrollableArea() const;
     55 
     56     virtual void styleWillChange(StyleDifference, const RenderStyle& newStyle) OVERRIDE;
     57     virtual void styleDidChange(StyleDifference, const RenderStyle* oldStyle) OVERRIDE;
     58     virtual void updateFromStyle() { }
     59 
     60     virtual LayerType layerTypeRequired() const = 0;
     61 
     62     // Returns true if the background is painted opaque in the given rect.
     63     // The query rect is given in local coordinate system.
     64     virtual bool backgroundIsKnownToBeOpaqueInRect(const LayoutRect&) const { return false; }
     65 
     66     // This is null for anonymous renderers.
     67     ContainerNode* node() const { return toContainerNode(RenderObject::node()); }
     68 
     69     CompositedLayerMappingPtr compositedLayerMapping() const;
     70     bool hasCompositedLayerMapping() const;
     71     CompositedLayerMapping* groupedMapping() const;
     72 
     73 protected:
     74     void createLayer(LayerType);
     75 
     76     virtual void willBeDestroyed() OVERRIDE;
     77 
     78     virtual void addLayerHitTestRects(LayerHitTestRects&, const RenderLayer*, const LayoutPoint&, const LayoutRect&) const OVERRIDE;
     79 
     80 private:
     81     virtual bool isLayerModelObject() const OVERRIDE FINAL { return true; }
     82 
     83     OwnPtr<RenderLayer> m_layer;
     84 
     85     // Used to store state between styleWillChange and styleDidChange
     86     static bool s_wasFloating;
     87 };
     88 
     89 DEFINE_RENDER_OBJECT_TYPE_CASTS(RenderLayerModelObject, isLayerModelObject());
     90 
     91 } // namespace WebCore
     92 
     93 #endif // RenderLayerModelObject_h
     94