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 namespace blink { 46 47 class FloatPoint; 48 class FloatRect; 49 class FloatSize; 50 class GraphicsContext; 51 52 // This object is used as the "native image" in our port. When WebKit uses 53 // PassNativeImagePtr / NativeImagePtr, it is a smart pointer to this type. 54 // It has an SkBitmap, and also stores a cached resized image. 55 class PLATFORM_EXPORT NativeImageSkia : public RefCounted<NativeImageSkia> { 56 public: create()57 static PassRefPtr<NativeImageSkia> create() 58 { 59 return adoptRef(new NativeImageSkia()); 60 } 61 62 // This factory method does a shallow copy of the passed-in SkBitmap 63 // (ie., it references the same pixel data and bumps the refcount). Use 64 // only when you want sharing semantics. create(const SkBitmap & bitmap)65 static PassRefPtr<NativeImageSkia> create(const SkBitmap& bitmap) 66 { 67 return adoptRef(new NativeImageSkia(bitmap)); 68 } 69 70 ~NativeImageSkia(); 71 72 // Returns true if the entire image has been decoded. isDataComplete()73 bool isDataComplete() const { return bitmap().isImmutable(); } 74 75 // Get reference to the internal SkBitmap representing this image. bitmap()76 const SkBitmap& bitmap() const { return m_bitmap; } 77 78 // We can keep a resized version of the bitmap cached on this object. 79 // This function will return true if there is a cached version of the given 80 // scale and subset. 81 bool hasResizedBitmap(const SkISize& scaledImageSize, const SkIRect& scaledImageSubset) const; 82 83 // This will return an existing resized image subset, or generate a new one 84 // of the specified size and subset and possibly cache it. 85 // 86 // scaledImageSize 87 // Dimensions of the scaled full image. 88 // 89 // scaledImageSubset 90 // Rectangle of the subset in the scaled image. 91 SkBitmap resizedBitmap(const SkISize& scaledImageSize, const SkIRect& scaledImageSubset) const; 92 93 void draw( 94 GraphicsContext*, 95 const SkRect& srcRect, 96 const SkRect& destRect, 97 CompositeOperator, 98 WebBlendMode) const; 99 100 void drawPattern( 101 GraphicsContext*, 102 const FloatRect& srcRect, 103 const FloatSize& scale, 104 const FloatPoint& phase, 105 CompositeOperator, 106 const FloatRect& destRect, 107 WebBlendMode, 108 const IntSize& repeatSpacing) const; 109 110 private: 111 NativeImageSkia(); 112 113 NativeImageSkia(const SkBitmap&); 114 115 // ImageResourceInfo is used to uniquely identify cached or requested image 116 // resizes. 117 // Image resize is identified by the scaled image size and scaled image subset. 118 struct ImageResourceInfo { 119 SkISize scaledImageSize; 120 SkIRect scaledImageSubset; 121 122 ImageResourceInfo(); 123 124 bool isEqual(const SkISize& otherScaledImageSize, const SkIRect& otherScaledImageSubset) const; 125 void set(const SkISize& otherScaledImageSize, const SkIRect& otherScaledImageSubset); 126 SkIRect rectInSubset(const SkIRect& otherScaledImageRect); 127 }; 128 129 // Returns true if the given resize operation should either resize the whole 130 // image and cache it, or resize just the part it needs and throw the result 131 // away. 132 // 133 // Calling this function may increment a request count that can change the 134 // result of subsequent calls. 135 // 136 // On the one hand, if only a small subset is desired, then we will waste a 137 // lot of time resampling the entire thing, so we only want to do exactly 138 // what's required. On the other hand, resampling the entire bitmap is 139 // better if we're going to be using it more than once (like a bitmap 140 // scrolling on and off the screen. Since we only cache when doing the 141 // entire thing, it's best to just do it up front. 142 bool shouldCacheResampling(const SkISize& scaledImageSize, const SkIRect& scaledImageSubset) const; 143 144 SkBitmap extractScaledImageFragment(const SkRect& srcRect, float scaleX, float scaleY, SkRect* scaledSrcRect) const; 145 146 // The original image. 147 SkBitmap m_bitmap; 148 149 // The cached bitmap fragment. This is a subset of the scaled version of 150 // |m_bitmap|. empty() returns true if there is no cached image. 151 mutable SkBitmap m_resizedImage; 152 153 // References how many times that the image size has been requested for 154 // the last size. 155 // 156 // Every time we get a call to shouldCacheResampling, if it matches the 157 // m_cachedImageInfo, we'll increment the counter, and if not, we'll reset 158 // the counter and save the dimensions. 159 // 160 // This allows us to see if many requests have been made for the same 161 // resized image, we know that we should probably cache it, even if all of 162 // those requests individually are small and would not otherwise be cached. 163 // 164 // We also track scaling information and destination subset for the scaled 165 // image. See comments for ImageResourceInfo. 166 mutable ImageResourceInfo m_cachedImageInfo; 167 mutable int m_resizeRequests; 168 }; 169 170 } // namespace blink 171 172 #endif // NativeImageSkia_h 173