gecko-dev/gfx/layers/ReadbackProcessor.h
2012-07-30 17:20:58 +03:00

75 lines
2.6 KiB
C++

/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*-
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef GFX_READBACKPROCESSOR_H
#define GFX_READBACKPROCESSOR_H
#include "ReadbackLayer.h"
#include "ThebesLayerBuffer.h"
#include "nsTArray.h"
namespace mozilla {
namespace layers {
class ReadbackProcessor {
public:
/**
* Called by the container before processing any child layers. Call this
* if any child layer might have changed in any way (other than content-only
* changes to layers other than ColorLayers and ThebesLayers).
*
* This method recomputes the relationship between ReadbackLayers and
* sibling layers, and dispatches changes to ReadbackLayers. Except that
* if a ThebesLayer needs its contents sent to some ReadbackLayer, we'll
* just record that internally and later the ThebesLayer should call
* GetThebesLayerUpdates when it paints, to find out which rectangle needs
* to be sent, and the ReadbackLayer it needs to be sent to.
*/
void BuildUpdates(ContainerLayer* aContainer);
struct Update {
/**
* The layer a ThebesLayer should send its contents to.
*/
ReadbackLayer* mLayer;
/**
* The rectangle of content that it should send, in the ThebesLayer's
* coordinate system. This rectangle is guaranteed to be in the ThebesLayer's
* visible region. Translate it to mLayer's coordinate system
* by adding mLayer->GetBackgroundLayerOffset().
*/
nsIntRect mUpdateRect;
/**
* The sequence counter value to use when calling DoUpdate
*/
PRUint64 mSequenceCounter;
};
/**
* Appends any ReadbackLayers that need to be updated, and the rects that
* need to be updated, to aUpdates. Only need to call this for ThebesLayers
* that have been marked UsedForReadback().
* Each Update's mLayer's mBackgroundLayer will have been set to aLayer.
* If a ThebesLayer doesn't call GetThebesLayerUpdates, then all the
* ReadbackLayers that needed data from that ThebesLayer will be marked
* as having unknown backgrounds.
* @param aUpdateRegion if non-null, this region is set to the union
* of the mUpdateRects.
*/
void GetThebesLayerUpdates(ThebesLayer* aLayer,
nsTArray<Update>* aUpdates,
nsIntRegion* aUpdateRegion = nullptr);
~ReadbackProcessor();
protected:
void BuildUpdatesForLayer(ReadbackLayer* aLayer);
nsTArray<Update> mAllUpdates;
};
}
}
#endif /* GFX_READBACKPROCESSOR_H */