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 "platform/PlatformExport.h" 39 #include "platform/geometry/IntSize.h" 40 #include "platform/graphics/GraphicsTypes.h" 41 #include "wtf/Forward.h" 42 #include "wtf/PassRefPtr.h" 43 #include "wtf/RefCounted.h" 44 45 class SkMatrix; 46 class SkPaint; 47 48 namespace WebCore { 49 50 class FloatPoint; 51 class FloatRect; 52 class FloatSize; 53 class GraphicsContext; 54 55 // Used by computeResamplingMode to tell how bitmaps should be resampled. 56 enum ResamplingMode { 57 // Nearest neighbor resampling. Used when we detect that the page is 58 // trying to make a pattern by stretching a small bitmap very large. 59 NoResampling, 60 61 // Default skia resampling. Used for large growing of images where high 62 // quality resampling doesn't get us very much except a slowdown. 63 LinearResampling, 64 65 // High quality resampling. 66 AwesomeResampling, 67 }; 68 69 // This object is used as the "native image" in our port. When WebKit uses 70 // PassNativeImagePtr / NativeImagePtr, it is a smart pointer to this type. 71 // It has an SkBitmap, and also stores a cached resized image. 72 class PLATFORM_EXPORT NativeImageSkia : public RefCounted<NativeImageSkia> { 73 public: create()74 static PassRefPtr<NativeImageSkia> create() 75 { 76 return adoptRef(new NativeImageSkia()); 77 } 78 79 // This factory method does a shallow copy of the passed-in SkBitmap 80 // (ie., it references the same pixel data and bumps the refcount). Use 81 // only when you want sharing semantics. create(const SkBitmap & bitmap)82 static PassRefPtr<NativeImageSkia> create(const SkBitmap& bitmap) 83 { 84 return adoptRef(new NativeImageSkia(bitmap)); 85 } 86 87 // This method does a shallow copy of the internal SkBitmap (ie., it 88 // references the same pixel data and bumps the refcount). Use only when 89 // you want sharing semantics. clone()90 PassRefPtr<NativeImageSkia> clone() const 91 { 92 return adoptRef(new NativeImageSkia(m_image, m_resizedImage, m_cachedImageInfo, m_resizeRequests)); 93 } 94 95 ~NativeImageSkia(); 96 97 // Returns the number of bytes of image data. This includes the cached 98 // resized version if there is one. 99 int decodedSize() const; 100 101 // Sets the immutable flag on the bitmap, indicating that the image data 102 // will not be modified any further. This is called by the image decoder 103 // when all data is complete, used by us to know whether we can cache 104 // resized images, and used by Skia for various optimizations. setDataComplete()105 void setDataComplete() { m_image.setImmutable(); } 106 107 // Returns true if the entire image has been decoded. isDataComplete()108 bool isDataComplete() const { return m_image.isImmutable(); } 109 110 // Get reference to the internal SkBitmap representing this image. bitmap()111 const SkBitmap& bitmap() const { return m_image; } bitmap()112 SkBitmap& bitmap() { return m_image; } 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, PassRefPtr<SkXfermode>) 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 blink::WebBlendMode, 138 const IntSize& repeatSpacing) const; 139 140 private: 141 NativeImageSkia(); 142 143 NativeImageSkia(const SkBitmap&); 144 145 // ImageResourceInfo is used to uniquely identify cached or requested image 146 // resizes. 147 // Image resize is identified by the scaled image size and scaled image subset. 148 struct ImageResourceInfo { 149 SkISize scaledImageSize; 150 SkIRect scaledImageSubset; 151 152 ImageResourceInfo(); 153 154 bool isEqual(const SkISize& otherScaledImageSize, const SkIRect& otherScaledImageSubset) const; 155 void set(const SkISize& otherScaledImageSize, const SkIRect& otherScaledImageSubset); 156 SkIRect rectInSubset(const SkIRect& otherScaledImageRect); 157 }; 158 159 NativeImageSkia(const SkBitmap& image, const SkBitmap& resizedImage, const ImageResourceInfo&, int resizeRequests); 160 161 // Returns true if the given resize operation should either resize the whole 162 // image and cache it, or resize just the part it needs and throw the result 163 // away. 164 // 165 // Calling this function may increment a request count that can change the 166 // result of subsequent calls. 167 // 168 // On the one hand, if only a small subset is desired, then we will waste a 169 // lot of time resampling the entire thing, so we only want to do exactly 170 // what's required. On the other hand, resampling the entire bitmap is 171 // better if we're going to be using it more than once (like a bitmap 172 // scrolling on and off the screen. Since we only cache when doing the 173 // entire thing, it's best to just do it up front. 174 bool shouldCacheResampling(const SkISize& scaledImageSize, const SkIRect& scaledImageSubset) const; 175 176 ResamplingMode computeResamplingMode(const SkMatrix&, float srcWidth, float srcHeight, float destWidth, float destHeight) const; 177 SkBitmap extractScaledImageFragment(const SkRect& srcRect, float scaleX, float scaleY, SkRect* scaledSrcRect) const; 178 void drawResampledBitmap(GraphicsContext*, SkPaint&, const SkRect& srcRect, const SkRect& destRect) const; 179 180 // The original image. 181 SkBitmap m_image; 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