Source/core/platform/graphics/chromium/LazyDecodingPixelRef.h

/*
 * Copyright (C) 2012 Google Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1.  Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 * 2.  Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef LazyDecodingPixelRef_h
#define LazyDecodingPixelRef_h

#include "SkFlattenableBuffers.h"
#include "SkPixelRef.h"
#include "SkRect.h"
#include "SkSize.h"
#include "SkTypes.h"
#include "core/platform/PlatformInstrumentation.h"
#include "skia/ext/lazy_pixel_ref.h"

#include "wtf/RefPtr.h"

using skia::LazyPixelRef;

class SkData;

namespace WebCore {

class ImageFrameGenerator;
class ScaledImageFragment;

class LazyDecodingPixelRef : public LazyPixelRef {
public:
    LazyDecodingPixelRef(PassRefPtr<ImageFrameGenerator>, const SkISize& scaledSize, size_t index, const SkIRect& scaledSubset);
    virtual ~LazyDecodingPixelRef();

    SK_DECLARE_UNFLATTENABLE_OBJECT()

    PassRefPtr<ImageFrameGenerator> frameGenerator() const { return m_frameGenerator; }
    size_t frameIndex() const { return m_frameIndex; }
    bool isScaled(const SkISize& fullSize) const;
    bool isClipped() const;

    // Returns true if the image might already be decoded in the cache.
    // Optimistic version of PrepareToDecode; requires less locking.
    virtual bool MaybeDecoded();
    virtual bool PrepareToDecode(const LazyPixelRef::PrepareParams&);
    virtual void Decode();

protected:
    // SkPixelRef implementation.
    virtual void* onLockPixels(SkColorTable**);
    virtual void onUnlockPixels();
    virtual bool onLockPixelsAreWritable() const;

    virtual SkData* onRefEncodedData() SK_OVERRIDE;

private:
    RefPtr<ImageFrameGenerator> m_frameGenerator;
    size_t m_frameIndex;
    SkISize m_scaledSize;
    SkIRect m_scaledSubset;

    const ScaledImageFragment* m_lockedImageResource;
    PlatformInstrumentation::LazyPixelRefTracker m_objectTracker;
};

} // namespace WebCore

#endif // LazyDecodingPixelRef_h_