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// Copyright 2011 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.
#ifndef CCDamageTracker_h
#define CCDamageTracker_h
#include "base/memory/scoped_ptr.h"
#include "FloatRect.h"
#include <vector>
#include <wtf/HashMap.h>
#include <wtf/Vector.h>
namespace WebKit {
class WebFilterOperations;
}
namespace cc {
class CCLayerImpl;
class CCRenderSurface;
// Computes the region where pixels have actually changed on a RenderSurface. This region is used
// to scissor what is actually drawn to the screen to save GPU computation and bandwidth.
class CCDamageTracker {
public:
static scoped_ptr<CCDamageTracker> create();
~CCDamageTracker();
void didDrawDamagedArea() { m_currentDamageRect = FloatRect(); }
void forceFullDamageNextUpdate() { m_forceFullDamageNextUpdate = true; }
void updateDamageTrackingState(const std::vector<CCLayerImpl*>& layerList, int targetSurfaceLayerID, bool targetSurfacePropertyChangedOnlyFromDescendant, const IntRect& targetSurfaceContentRect, CCLayerImpl* targetSurfaceMaskLayer, const WebKit::WebFilterOperations&);
const FloatRect& currentDamageRect() { return m_currentDamageRect; }
private:
CCDamageTracker();
FloatRect trackDamageFromActiveLayers(const std::vector<CCLayerImpl*>& layerList, int targetSurfaceLayerID);
FloatRect trackDamageFromSurfaceMask(CCLayerImpl* targetSurfaceMaskLayer);
FloatRect trackDamageFromLeftoverRects();
FloatRect removeRectFromCurrentFrame(int layerID, bool& layerIsNew);
void saveRectForNextFrame(int layerID, const FloatRect& targetSpaceRect);
// These helper functions are used only in trackDamageFromActiveLayers().
void extendDamageForLayer(CCLayerImpl*, FloatRect& targetDamageRect);
void extendDamageForRenderSurface(CCLayerImpl*, FloatRect& targetDamageRect);
// To correctly track exposed regions, two hashtables of rects are maintained.
// The "current" map is used to compute exposed regions of the current frame, while
// the "next" map is used to collect layer rects that are used in the next frame.
typedef HashMap<int, FloatRect> RectMap;
scoped_ptr<RectMap> m_currentRectHistory;
scoped_ptr<RectMap> m_nextRectHistory;
FloatRect m_currentDamageRect;
bool m_forceFullDamageNextUpdate;
};
} // namespace cc
#endif // CCDamageTracker_h
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