DecodingImageGenerator implmentation of SkImageGenerator

Source/core/platform/graphics/DecodingImageGenerator.h

+/*
+ * Copyright (C) 2013 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 COMPUTER, INC. ``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 COMPUTER, INC. OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
+ * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef DecodingImageGenerator_h
+#define DecodingImageGenerator_h
+
+#include "ImageFrameGenerator.h"
+#include "third_party/skia/include/core/SkImageGenerator.h"
+
+/**
+ *  Blink's implementation of the Skia SkImageGenerator interface
+ *  (allows a SkDiscardablePixelRef to re-decode an image).
+ */
+namespace WebCore {
+
+class DecodingImageGenerator : public SkImageGenerator {
+public:
+    static bool Install(PassRefPtr<ImageFrameGenerator>, size_t index, SkBitmap* dst);
+
+    DecodingImageGenerator(PassRefPtr<ImageFrameGenerator>, size_t index);
+    virtual ~DecodingImageGenerator();
+
+    /**
+     *  Return a ref to the encoded (i.e. compressed) representation,
+     *  of this data.
+     *
+     *  If non-NULL is returned, the caller is responsible for calling
+     *  unref() on the data when it is finished.
+     */
+    virtual SkData* refEncodedData() SK_OVERRIDE;
+
+    /**
+     *  Return some information about the image, allowing the owner fo
+     *  this object to allocate pixels.
+     *
+     *  @return false if anything goes wrong.
+     */
+    virtual bool getInfo(SkImageInfo*) SK_OVERRIDE;
+
+    /**
+     *  Decode into the given pixels, a block of memory of size at
+     *  least (info.fHeight - 1) * rowBytes + (info.fWidth *
+     *  bytesPerPixel)
+     *
+     *  @param SkImageInfo Should be identical to the info returned by
+     *         getInfo so that the implementation will confirm that
+     *         the caller knows what it is asking for (config, size).
+     *
+     *  @return false if anything goes wrong.
+     */
+    virtual bool getPixels(const SkImageInfo&, void* pixels, size_t rowBytes) SK_OVERRIDE;
+private:
+    RefPtr<ImageFrameGenerator> m_frameGenerator;
+    size_t m_frameIndex;
+};
+} // namespace WebCore
+#endif // DecodingImageGenerator_h