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* Copyright (c) 2008, Google Inc. All rights reserved.
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above
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* copyright notice, this list of conditions and the following disclaimer
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* in the documentation and/or other materials provided with the
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* * Neither the name of Google Inc. nor the names of its
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* contributors may be used to endorse or promote products derived from
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* this software without specific prior written permission.
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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#ifndef NativeImageSkia_h
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#define NativeImageSkia_h
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#include <wtf/Forward.h>
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// This object is used as the "native image" in our port. When WebKit uses
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// "NativeImagePtr", it is a pointer to this type. It has an SkBitmap, and also
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// stores a cached resized image.
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class NativeImageSkia {
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// This constructor does a shallow copy of the passed-in SkBitmap (ie., it
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// references the same pixel data and bumps the refcount). Use only when
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// you want sharing semantics.
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NativeImageSkia(const SkBitmap&, float resolutionScale);
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// Returns the number of bytes of image data. This includes the cached
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// resized version if there is one.
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int decodedSize() const;
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// Sets the immutable flag on the bitmap, indicating that the image data
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// will not be modified any further. This is called by the image decoder
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// when all data is complete, used by us to know whether we can cache
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// resized images, and used by Skia for various optimizations.
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void setDataComplete() { m_image.setImmutable(); }
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// Returns true if the entire image has been decoded.
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bool isDataComplete() const { return m_image.isImmutable(); }
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// Get reference to the internal SkBitmap representing this image.
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const SkBitmap& bitmap() const { return m_image; }
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SkBitmap& bitmap() { return m_image; }
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float resolutionScale() const { return m_resolutionScale; }
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// We can keep a resized version of the bitmap cached on this object.
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// This function will return true if there is a cached version of the given
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bool hasResizedBitmap(const SkISize& scaledImageSize, const SkIRect& scaledImageSubset) const;
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// This will return an existing resized image subset, or generate a new one
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// of the specified size and subset and possibly cache it.
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// Dimensions of the scaled full image.
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// Rectangle of the subset in the scaled image.
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SkBitmap resizedBitmap(const SkISize& scaledImageSize, const SkIRect& scaledImageSubset) const;
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void reportMemoryUsage(MemoryObjectInfo*) const;
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// CachedImageInfo is used to uniquely identify cached or requested image
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// Image resize is identified by the scaled image size and scaled image subset.
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struct CachedImageInfo {
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SkISize scaledImageSize;
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SkIRect scaledImageSubset;
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bool isEqual(const SkISize& otherScaledImageSize, const SkIRect& otherScaledImageSubset) const;
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void set(const SkISize& otherScaledImageSize, const SkIRect& otherScaledImageSubset);
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SkIRect rectInSubset(const SkIRect& otherScaledImageRect);
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// Returns true if the given resize operation should either resize the whole
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// image and cache it, or resize just the part it needs and throw the result
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// Calling this function may increment a request count that can change the
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// result of subsequent calls.
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// On the one hand, if only a small subset is desired, then we will waste a
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// lot of time resampling the entire thing, so we only want to do exactly
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// what's required. On the other hand, resampling the entire bitmap is
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// better if we're going to be using it more than once (like a bitmap
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// scrolling on and off the screen. Since we only cache when doing the
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// entire thing, it's best to just do it up front.
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bool shouldCacheResampling(const SkISize& scaledImageSize, const SkIRect& scaledImageSubset) const;
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// The original image.
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float m_resolutionScale;
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// The cached bitmap fragment. This is a subset of the scaled version of
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// |m_image|. empty() returns true if there is no cached image.
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mutable SkBitmap m_resizedImage;
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// References how many times that the image size has been requested for
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// Every time we get a call to shouldCacheResampling, if it matches the
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// m_cachedImageInfo, we'll increment the counter, and if not, we'll reset
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// the counter and save the dimensions.
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// This allows us to see if many requests have been made for the same
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// resized image, we know that we should probably cache it, even if all of
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// those requests individually are small and would not otherwise be cached.
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// We also track scaling information and destination subset for the scaled
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// image. See comments for CachedImageInfo.
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mutable CachedImageInfo m_cachedImageInfo;
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mutable int m_resizeRequests;
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#endif // NativeImageSkia_h