1 /* 2 * Copyright (c) 2008, Google Inc. All rights reserved. 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions are 6 * met: 7 * 8 * * Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * * Redistributions in binary form must reproduce the above 11 * copyright notice, this list of conditions and the following disclaimer 12 * in the documentation and/or other materials provided with the 13 * distribution. 14 * * Neither the name of Google Inc. nor the names of its 15 * contributors may be used to endorse or promote products derived from 16 * this software without specific prior written permission. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 19 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 20 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 21 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 22 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 23 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 24 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 28 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 29 */ 30 31 #ifndef NativeImageSkia_h 32 #define NativeImageSkia_h 33 34 #include "SkBitmap.h" 35 #include "SkRect.h" 36 #include "SkSize.h" 37 #include "SkXfermode.h" 38 #include "core/platform/graphics/GraphicsTypes.h" 39 #include "wtf/Forward.h" 40 #include "wtf/PassRefPtr.h" 41 #include "wtf/RefCounted.h" 42 43 class SkMatrix; 44 class SkPaint; 45 46 namespace WebCore { 47 48 class FloatPoint; 49 class FloatRect; 50 class FloatSize; 51 class GraphicsContext; 52 53 // Used by computeResamplingMode to tell how bitmaps should be resampled. 54 enum ResamplingMode { 55 // Nearest neighbor resampling. Used when we detect that the page is 56 // trying to make a pattern by stretching a small bitmap very large. 57 NoResampling, 58 59 // Default skia resampling. Used for large growing of images where high 60 // quality resampling doesn't get us very much except a slowdown. 61 LinearResampling, 62 63 // High quality resampling. 64 AwesomeResampling, 65 }; 66 67 // This object is used as the "native image" in our port. When WebKit uses 68 // PassNativeImagePtr / NativeImagePtr, it is a smart pointer to this type. 69 // It has an SkBitmap, and also stores a cached resized image. 70 class NativeImageSkia : public RefCounted<NativeImageSkia> { 71 public: 72 static PassRefPtr<NativeImageSkia> create() 73 { 74 return adoptRef(new NativeImageSkia()); 75 } 76 77 // This factory method does a shallow copy of the passed-in SkBitmap 78 // (ie., it references the same pixel data and bumps the refcount). Use 79 // only when you want sharing semantics. 80 static PassRefPtr<NativeImageSkia> create(const SkBitmap& bitmap, float resolutionScale = 1) 81 { 82 return adoptRef(new NativeImageSkia(bitmap, resolutionScale)); 83 } 84 85 // This method does a shallow copy of the internal SkBitmap (ie., it 86 // references the same pixel data and bumps the refcount). Use only when 87 // you want sharing semantics. 88 PassRefPtr<NativeImageSkia> clone() const 89 { 90 return adoptRef(new NativeImageSkia(m_image, m_resolutionScale, m_resizedImage, m_cachedImageInfo, m_resizeRequests)); 91 } 92 93 ~NativeImageSkia(); 94 95 // Returns the number of bytes of image data. This includes the cached 96 // resized version if there is one. 97 int decodedSize() const; 98 99 // Sets the immutable flag on the bitmap, indicating that the image data 100 // will not be modified any further. This is called by the image decoder 101 // when all data is complete, used by us to know whether we can cache 102 // resized images, and used by Skia for various optimizations. 103 void setDataComplete() { m_image.setImmutable(); } 104 105 // Returns true if the entire image has been decoded. 106 bool isDataComplete() const { return m_image.isImmutable(); } 107 108 // Get reference to the internal SkBitmap representing this image. 109 const SkBitmap& bitmap() const { return m_image; } 110 SkBitmap& bitmap() { return m_image; } 111 112 float resolutionScale() const { return m_resolutionScale; } 113 114 // We can keep a resized version of the bitmap cached on this object. 115 // This function will return true if there is a cached version of the given 116 // scale and subset. 117 bool hasResizedBitmap(const SkISize& scaledImageSize, const SkIRect& scaledImageSubset) const; 118 119 // This will return an existing resized image subset, or generate a new one 120 // of the specified size and subset and possibly cache it. 121 // 122 // scaledImageSize 123 // Dimensions of the scaled full image. 124 // 125 // scaledImageSubset 126 // Rectangle of the subset in the scaled image. 127 SkBitmap resizedBitmap(const SkISize& scaledImageSize, const SkIRect& scaledImageSubset) const; 128 129 void draw(GraphicsContext*, const SkRect& srcRect, const SkRect& destRect, SkXfermode::Mode) const; 130 void drawPattern( 131 GraphicsContext*, 132 const FloatRect& srcRect, 133 const FloatSize& scale, 134 const FloatPoint& phase, 135 CompositeOperator, 136 const FloatRect& destRect, 137 BlendMode) const; 138 139 private: 140 NativeImageSkia(); 141 142 NativeImageSkia(const SkBitmap&, float resolutionScale); 143 144 // ImageResourceInfo is used to uniquely identify cached or requested image 145 // resizes. 146 // Image resize is identified by the scaled image size and scaled image subset. 147 struct ImageResourceInfo { 148 SkISize scaledImageSize; 149 SkIRect scaledImageSubset; 150 151 ImageResourceInfo(); 152 153 bool isEqual(const SkISize& otherScaledImageSize, const SkIRect& otherScaledImageSubset) const; 154 void set(const SkISize& otherScaledImageSize, const SkIRect& otherScaledImageSubset); 155 SkIRect rectInSubset(const SkIRect& otherScaledImageRect); 156 }; 157 158 NativeImageSkia(const SkBitmap& image, float resolutionScale, const SkBitmap& resizedImage, const ImageResourceInfo&, int resizeRequests); 159 160 // Returns true if the given resize operation should either resize the whole 161 // image and cache it, or resize just the part it needs and throw the result 162 // away. 163 // 164 // Calling this function may increment a request count that can change the 165 // result of subsequent calls. 166 // 167 // On the one hand, if only a small subset is desired, then we will waste a 168 // lot of time resampling the entire thing, so we only want to do exactly 169 // what's required. On the other hand, resampling the entire bitmap is 170 // better if we're going to be using it more than once (like a bitmap 171 // scrolling on and off the screen. Since we only cache when doing the 172 // entire thing, it's best to just do it up front. 173 bool shouldCacheResampling(const SkISize& scaledImageSize, const SkIRect& scaledImageSubset) const; 174 175 ResamplingMode computeResamplingMode(const SkMatrix&, float srcWidth, float srcHeight, float destWidth, float destHeight) const; 176 SkBitmap extractScaledImageFragment(const SkRect& srcRect, float scaleX, float scaleY, SkRect* scaledSrcRect) const; 177 void drawResampledBitmap(GraphicsContext*, SkPaint&, const SkRect& srcRect, const SkRect& destRect) const; 178 179 // The original image. 180 SkBitmap m_image; 181 float m_resolutionScale; 182 183 // The cached bitmap fragment. This is a subset of the scaled version of 184 // |m_image|. empty() returns true if there is no cached image. 185 mutable SkBitmap m_resizedImage; 186 187 // References how many times that the image size has been requested for 188 // the last size. 189 // 190 // Every time we get a call to shouldCacheResampling, if it matches the 191 // m_cachedImageInfo, we'll increment the counter, and if not, we'll reset 192 // the counter and save the dimensions. 193 // 194 // This allows us to see if many requests have been made for the same 195 // resized image, we know that we should probably cache it, even if all of 196 // those requests individually are small and would not otherwise be cached. 197 // 198 // We also track scaling information and destination subset for the scaled 199 // image. See comments for ImageResourceInfo. 200 mutable ImageResourceInfo m_cachedImageInfo; 201 mutable int m_resizeRequests; 202 }; 203 204 } 205 #endif // NativeImageSkia_h 206