/* * Copyright (c) 2008, 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: * * * Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * 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. * * Neither the name of Google Inc. nor the names of its * contributors may be used to endorse or promote products derived from * this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND 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 THE COPYRIGHT * OWNER 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 NativeImageSkia_h #define NativeImageSkia_h #include "SkBitmap.h" #include "SkRect.h" #include "IntSize.h" namespace WebCore { // This object is used as the "native image" in our port. When WebKit uses // "NativeImagePtr", it is a pointer to this type. It has an SkBitmap, and also // stores a cached resized image. class NativeImageSkia { public: NativeImageSkia(); ~NativeImageSkia(); // This constructor does a shallow copy of the passed-in SkBitmap (ie., it // references the same pixel data and bumps the refcount). Use only when // you want sharing semantics. explicit NativeImageSkia(const SkBitmap&); // Returns the number of bytes of image data. This includes the cached // resized version if there is one. int decodedSize() const; // Sets the immutable flag on the bitmap, indicating that the image data // will not be modified any further. This is called by the image decoder // when all data is complete, used by us to know whether we can cache // resized images, and used by Skia for various optimizations. void setDataComplete() { m_image.setImmutable(); } // Returns true if the entire image has been decoded. bool isDataComplete() const { return m_image.isImmutable(); } // Get reference to the internal SkBitmap representing this image. const SkBitmap& bitmap() const { return m_image; } SkBitmap& bitmap() { return m_image; } // We can keep a resized version of the bitmap cached on this object. // This function will return true if there is a cached version of the // given image subset with the given dimensions and subsets. bool hasResizedBitmap(const SkIRect& srcSubset, int width, int height) const; // This will return an existing resized image subset, or generate a new one // of the specified size and subsets and possibly cache it. // srcSubset is the subset of the image to resize in image space. SkBitmap resizedBitmap(const SkIRect& srcSubset, int destWidth, int destHeight) const { SkIRect destVisibleSubset = {0, 0, destWidth, destHeight}; return resizedBitmap(srcSubset, destWidth, destHeight, destVisibleSubset); } // Same as above, but returns a subset of the destination image (ie: the // visible subset). destVisibleSubset is the subset of the resized // (destWidth x destHeight) image. // In other words: // - crop image by srcSubset -> imageSubset. // - resize imageSubset to destWidth x destHeight -> destImage. // - return destImage cropped by destVisibleSubset. SkBitmap resizedBitmap(const SkIRect& srcSubset, int destWidth, int destHeight, const SkIRect& destVisibleSubset) const; private: // CachedImageInfo is used to uniquely identify cached or requested image // resizes. struct CachedImageInfo { IntSize requestSize; SkIRect srcSubset; CachedImageInfo(); bool isEqual(const SkIRect& otherSrcSubset, int width, int height) const; void set(const SkIRect& otherSrcSubset, int width, int height); }; // Returns true if the given resize operation should either resize the whole // image and cache it, or resize just the part it needs and throw the result // away. // // Calling this function may increment a request count that can change the // result of subsequent calls. // // On the one hand, if only a small subset is desired, then we will waste a // lot of time resampling the entire thing, so we only want to do exactly // what's required. On the other hand, resampling the entire bitmap is // better if we're going to be using it more than once (like a bitmap // scrolling on and off the screen. Since we only cache when doing the // entire thing, it's best to just do it up front. bool shouldCacheResampling(const SkIRect& srcSubset, int destWidth, int destHeight, const SkIRect& destSubset) const; // The original image. SkBitmap m_image; // The cached bitmap. This will be empty() if there is no cached image. mutable SkBitmap m_resizedImage; // References how many times that the image size has been requested for // the last size. // // Every time we get a call to shouldCacheResampling, if it matches the // m_cachedImageInfo, we'll increment the counter, and if not, we'll reset // the counter and save the dimensions. // // This allows us to see if many requests have been made for the same // resized image, we know that we should probably cache it, even if all of // those requests individually are small and would not otherwise be cached. // // We also track the source and destination subsets for caching partial // image resizes. mutable CachedImageInfo m_cachedImageInfo; mutable int m_resizeRequests; }; } #endif // NativeImageSkia_h