michael@0: /* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*-
michael@0:  * This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #ifndef GFX_READBACKPROCESSOR_H
michael@0: #define GFX_READBACKPROCESSOR_H
michael@0: 
michael@0: #include <stdint.h>                     // for uint64_t
michael@0: #include "nsRect.h"                     // for nsIntRect
michael@0: #include "nsTArray.h"                   // for nsTArray
michael@0:  
michael@0: class nsIntRegion;
michael@0: 
michael@0: namespace mozilla {
michael@0: namespace layers {
michael@0: 
michael@0: class ContainerLayer;
michael@0: class ReadbackLayer;
michael@0: class ThebesLayer;
michael@0: 
michael@0: class ReadbackProcessor {
michael@0: public:
michael@0:   /**
michael@0:    * Called by the container before processing any child layers. Call this
michael@0:    * if any child layer might have changed in any way (other than content-only
michael@0:    * changes to layers other than ColorLayers and ThebesLayers).
michael@0:    *
michael@0:    * This method recomputes the relationship between ReadbackLayers and
michael@0:    * sibling layers, and dispatches changes to ReadbackLayers. Except that
michael@0:    * if a ThebesLayer needs its contents sent to some ReadbackLayer, we'll
michael@0:    * just record that internally and later the ThebesLayer should call
michael@0:    * GetThebesLayerUpdates when it paints, to find out which rectangle needs
michael@0:    * to be sent, and the ReadbackLayer it needs to be sent to.
michael@0:    */
michael@0:   void BuildUpdates(ContainerLayer* aContainer);
michael@0: 
michael@0:   struct Update {
michael@0:     /**
michael@0:      * The layer a ThebesLayer should send its contents to.
michael@0:      */
michael@0:     ReadbackLayer* mLayer;
michael@0:     /**
michael@0:      * The rectangle of content that it should send, in the ThebesLayer's
michael@0:      * coordinate system. This rectangle is guaranteed to be in the ThebesLayer's
michael@0:      * visible region. Translate it to mLayer's coordinate system
michael@0:      * by adding mLayer->GetBackgroundLayerOffset().
michael@0:      */
michael@0:     nsIntRect      mUpdateRect;
michael@0:     /**
michael@0:      * The sequence counter value to use when calling DoUpdate
michael@0:      */
michael@0:     uint64_t       mSequenceCounter;
michael@0:   };
michael@0:   /**
michael@0:    * Appends any ReadbackLayers that need to be updated, and the rects that
michael@0:    * need to be updated, to aUpdates. Only need to call this for ThebesLayers
michael@0:    * that have been marked UsedForReadback().
michael@0:    * Each Update's mLayer's mBackgroundLayer will have been set to aLayer.
michael@0:    * If a ThebesLayer doesn't call GetThebesLayerUpdates, then all the
michael@0:    * ReadbackLayers that needed data from that ThebesLayer will be marked
michael@0:    * as having unknown backgrounds.
michael@0:    * @param aUpdateRegion if non-null, this region is set to the union
michael@0:    * of the mUpdateRects.
michael@0:    */
michael@0:   void GetThebesLayerUpdates(ThebesLayer* aLayer,
michael@0:                              nsTArray<Update>* aUpdates,
michael@0:                              nsIntRegion* aUpdateRegion = nullptr);
michael@0: 
michael@0:   ~ReadbackProcessor();
michael@0: 
michael@0: protected:
michael@0:   void BuildUpdatesForLayer(ReadbackLayer* aLayer);
michael@0: 
michael@0:   nsTArray<Update> mAllUpdates;
michael@0: };
michael@0: 
michael@0: }
michael@0: }
michael@0: #endif /* GFX_READBACKPROCESSOR_H */