/*
* Copyright (C) 2011 Google Inc. All rights reserved.
*
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* modification, are permitted provided that the following conditions are
* met:
*
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* notice, this list of conditions and the following disclaimer.
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* copyright notice, this list of conditions and the following disclaimer
* in the documentation and/or other materials provided with the
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*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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#ifndef PaintAggregator_h
#define PaintAggregator_h
#include "platform/geometry/IntPoint.h"
#include "platform/geometry/IntRect.h"
#include "wtf/Vector.h"
namespace blink {
// This class is responsible for aggregating multiple invalidation and scroll
// commands to produce a scroll and repaint sequence.
class PaintAggregator {
public:
// This structure describes an aggregation of invalidateRect and scrollRect
// calls. If |scrollRect| is non-empty, then that rect should be scrolled
// by the amount specified by |scrollDelta|. If |paintRects| is non-empty,
// then those rects should be repainted. If |scrollRect| and |paintRects|
// are non-empty, then scrolling should be performed before repainting.
// |scrollDelta| can only specify scrolling in one direction (i.e., the x
// and y members cannot both be non-zero).
struct PendingUpdate {
PendingUpdate();
~PendingUpdate();
// Returns the rect damaged by scrolling within |scrollRect| by
// |scrollDelta|. This rect must be repainted.
WebCore::IntRect calculateScrollDamage() const;
// Returns the smallest rect containing all paint rects.
WebCore::IntRect calculatePaintBounds() const;
WebCore::IntPoint scrollDelta;
WebCore::IntRect scrollRect;
WTF::Vector<WebCore::IntRect> paintRects;
};
// There is a PendingUpdate if invalidateRect or scrollRect were called and
// ClearPendingUpdate was not called.
bool hasPendingUpdate() const;
void clearPendingUpdate();
// Fills |update| and clears the pending update.
void popPendingUpdate(PendingUpdate*);
// The given rect should be repainted.
void invalidateRect(const WebCore::IntRect&);
// The given rect should be scrolled by the given amounts.
void scrollRect(int dx, int dy, const WebCore::IntRect& clipRect);
private:
WebCore::IntRect scrollPaintRect(const WebCore::IntRect& paintRect, int dx, int dy) const;
bool shouldInvalidateScrollRect(const WebCore::IntRect&) const;
void invalidateScrollRect();
void combinePaintRects();
PendingUpdate m_update;
};
} // namespace blink
#endif