gecko-dev/gfx/layers/ReadbackProcessor.h

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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* 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 <stdint.h> // for uint64_t
#include "nsRect.h" // for mozilla::gfx::IntRect
#include "nsRegionFwd.h" // for nsIntRegion
#include "nsTArray.h" // for nsTArray
namespace mozilla {
namespace layers {
class ContainerLayer;
class ReadbackLayer;
class PaintedLayer;
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 PaintedLayers).
*
* This method recomputes the relationship between ReadbackLayers and
* sibling layers, and dispatches changes to ReadbackLayers. Except that
* if a PaintedLayer needs its contents sent to some ReadbackLayer, we'll
* just record that internally and later the PaintedLayer should call
* GetPaintedLayerUpdates 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 PaintedLayer should send its contents to.
*/
ReadbackLayer* mLayer;
/**
* The rectangle of content that it should send, in the PaintedLayer's
* coordinate system. This rectangle is guaranteed to be in the PaintedLayer's
* visible region. Translate it to mLayer's coordinate system
* by adding mLayer->GetBackgroundLayerOffset().
*/
gfx::IntRect mUpdateRect;
/**
* The sequence counter value to use when calling DoUpdate
*/
uint64_t 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 PaintedLayers
* that have been marked UsedForReadback().
* Each Update's mLayer's mBackgroundLayer will have been set to aLayer.
* If a PaintedLayer doesn't call GetPaintedLayerUpdates, then all the
* ReadbackLayers that needed data from that PaintedLayer will be marked
* as having unknown backgrounds.
* @param aUpdateRegion if non-null, this region is set to the union
* of the mUpdateRects.
*/
void GetPaintedLayerUpdates(PaintedLayer* aLayer,
nsTArray<Update>* aUpdates,
nsIntRegion* aUpdateRegion = nullptr);
~ReadbackProcessor();
protected:
void BuildUpdatesForLayer(ReadbackLayer* aLayer);
nsTArray<Update> mAllUpdates;
};
} // namespace layers
} // namespace mozilla
#endif /* GFX_READBACKPROCESSOR_H */