The Tor Browser: gfx/skia/trunk/src/lazy/SkCachingPixelRef.h@b8a032363ba2

Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6

     1 /*

     2  * Copyright 2013 Google Inc.

     3  *

     4  * Use of this source code is governed by a BSD-style license that can be

     5  * found in the LICENSE file.

     6  */

     8 #ifndef SkCachingPixelRef_DEFINED

     9 #define SkCachingPixelRef_DEFINED

    11 #include "SkImageInfo.h"

    12 #include "SkImageGenerator.h"

    13 #include "SkPixelRef.h"

    15 class SkColorTable;

    17 /**

    18  *  PixelRef which defers decoding until SkBitmap::lockPixels() is

    19  *  called.  Caches the decoded images in the global

    20  *  SkScaledImageCache.  When the pixels are unlocked, this cache may

    21  *  or be destroyed before the next lock.  If so, onLockPixels will

    22  *  attempt to re-decode.

    23  *

    24  *  Decoding is handled by the SkImageGenerator

    25  */

    26 class SkCachingPixelRef : public SkPixelRef {

    27 public:

    28     SK_DECLARE_INST_COUNT(SkCachingPixelRef)

    29     /**

    30      *  Takes ownership of SkImageGenerator.  If this method fails for

    31      *  whatever reason, it will return false and immediatetely delete

    32      *  the generator.  If it succeeds, it will modify destination

    33      *  bitmap.

    34      *

    35      *  If Install fails or when the SkCachingPixelRef that is

    36      *  installed into destination is destroyed, it will call

    37      *  SkDELETE() on the generator.  Therefore, generator should be

    38      *  allocated with SkNEW() or SkNEW_ARGS().

    39      */

    40     static bool Install(SkImageGenerator* gen, SkBitmap* dst);

    42 protected:

    43     virtual ~SkCachingPixelRef();

    44     virtual bool onNewLockPixels(LockRec*) SK_OVERRIDE;

    45     virtual void onUnlockPixels() SK_OVERRIDE;

    46     virtual bool onLockPixelsAreWritable() const SK_OVERRIDE { return false; }

    48     virtual SkData* onRefEncodedData() SK_OVERRIDE {

    49         return fImageGenerator->refEncodedData();

    50     }

    51     // No need to flatten this object. When flattening an SkBitmap,

    52     // SkWriteBuffer will check the encoded data and write that

    53     // instead.

    54     // Future implementations of SkWriteBuffer will need to

    55     // special case for onRefEncodedData as well.

    56     SK_DECLARE_UNFLATTENABLE_OBJECT()

    58 private:

    59     SkImageGenerator* const fImageGenerator;

    60     bool                    fErrorInDecoding;

    61     void*                   fScaledCacheId;

    62     const size_t            fRowBytes;

    64     SkCachingPixelRef(const SkImageInfo&, SkImageGenerator*, size_t rowBytes);

    66     typedef SkPixelRef INHERITED;

    67 };

    69 #endif  // SkCachingPixelRef_DEFINED

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