third_party/WebKit/Source/core/layout/compositing/CompositingRequirementsUpdater.h

/*
 * Copyright (C) 2009, 2010 Apple Inc. All rights reserved.
 * Copyright (C) 2014 Google Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
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 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
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#ifndef CompositingRequirementsUpdater_h
#define CompositingRequirementsUpdater_h

#include "platform/geometry/IntRect.h"
#include "platform/graphics/CompositingReasons.h"
#include "wtf/Allocator.h"
#include "wtf/Vector.h"

namespace blink {

class CompositingReasonFinder;
class PaintLayer;
class LayoutView;

class CompositingRequirementsUpdater {
  STACK_ALLOCATED();

 public:
  CompositingRequirementsUpdater(LayoutView&, CompositingReasonFinder&);
  ~CompositingRequirementsUpdater();

  //  Recurse through the layers in z-index and overflow order (which is
  //  equivalent to painting order)
  //  For the z-order children of a compositing layer:
  //      If a child layers has a compositing layer, then all subsequent layers
  //      must be compositing in order to render above that layer.
  //
  //      If a child in the negative z-order list is compositing, then the layer
  //      itself must be compositing so that its contents render over that
  //      child.  This implies that its positive z-index children must also be
  //      compositing.
  //
  void update(PaintLayer* root);

 private:
  class OverlapMap;
  class RecursionData;

  void updateRecursive(PaintLayer* ancestorLayer,
                       PaintLayer* currentLayer,
                       OverlapMap&,
                       RecursionData&,
                       bool& descendantHas3DTransform,
                       Vector<PaintLayer*>& unclippedDescendants,
                       IntRect& absoluteDescendantBoundingBox);

  LayoutView& m_layoutView;
  CompositingReasonFinder& m_compositingReasonFinder;
};

}  // namespace blink

#endif  // CompositingRequirementsUpdater_h