michael@0: /*
michael@0:  * Copyright 2013 Google Inc.
michael@0:  *
michael@0:  * Use of this source code is governed by a BSD-style license that can be
michael@0:  * found in the LICENSE file.
michael@0:  */
michael@0: 
michael@0: #ifndef SkCachingPixelRef_DEFINED
michael@0: #define SkCachingPixelRef_DEFINED
michael@0: 
michael@0: #include "SkImageInfo.h"
michael@0: #include "SkImageGenerator.h"
michael@0: #include "SkPixelRef.h"
michael@0: 
michael@0: class SkColorTable;
michael@0: 
michael@0: /**
michael@0:  *  PixelRef which defers decoding until SkBitmap::lockPixels() is
michael@0:  *  called.  Caches the decoded images in the global
michael@0:  *  SkScaledImageCache.  When the pixels are unlocked, this cache may
michael@0:  *  or be destroyed before the next lock.  If so, onLockPixels will
michael@0:  *  attempt to re-decode.
michael@0:  *
michael@0:  *  Decoding is handled by the SkImageGenerator
michael@0:  */
michael@0: class SkCachingPixelRef : public SkPixelRef {
michael@0: public:
michael@0:     SK_DECLARE_INST_COUNT(SkCachingPixelRef)
michael@0:     /**
michael@0:      *  Takes ownership of SkImageGenerator.  If this method fails for
michael@0:      *  whatever reason, it will return false and immediatetely delete
michael@0:      *  the generator.  If it succeeds, it will modify destination
michael@0:      *  bitmap.
michael@0:      *
michael@0:      *  If Install fails or when the SkCachingPixelRef that is
michael@0:      *  installed into destination is destroyed, it will call
michael@0:      *  SkDELETE() on the generator.  Therefore, generator should be
michael@0:      *  allocated with SkNEW() or SkNEW_ARGS().
michael@0:      */
michael@0:     static bool Install(SkImageGenerator* gen, SkBitmap* dst);
michael@0: 
michael@0: protected:
michael@0:     virtual ~SkCachingPixelRef();
michael@0:     virtual bool onNewLockPixels(LockRec*) SK_OVERRIDE;
michael@0:     virtual void onUnlockPixels() SK_OVERRIDE;
michael@0:     virtual bool onLockPixelsAreWritable() const SK_OVERRIDE { return false; }
michael@0: 
michael@0:     virtual SkData* onRefEncodedData() SK_OVERRIDE {
michael@0:         return fImageGenerator->refEncodedData();
michael@0:     }
michael@0:     // No need to flatten this object. When flattening an SkBitmap,
michael@0:     // SkWriteBuffer will check the encoded data and write that
michael@0:     // instead.
michael@0:     // Future implementations of SkWriteBuffer will need to
michael@0:     // special case for onRefEncodedData as well.
michael@0:     SK_DECLARE_UNFLATTENABLE_OBJECT()
michael@0: 
michael@0: private:
michael@0:     SkImageGenerator* const fImageGenerator;
michael@0:     bool                    fErrorInDecoding;
michael@0:     void*                   fScaledCacheId;
michael@0:     const size_t            fRowBytes;
michael@0: 
michael@0:     SkCachingPixelRef(const SkImageInfo&, SkImageGenerator*, size_t rowBytes);
michael@0: 
michael@0:     typedef SkPixelRef INHERITED;
michael@0: };
michael@0: 
michael@0: #endif  // SkCachingPixelRef_DEFINED