1 /* 2 * Copyright 2008 The Android Open Source Project 3 * 4 * Use of this source code is governed by a BSD-style license that can be 5 * found in the LICENSE file. 6 */ 7 8 #ifndef SkPixelRef_DEFINED 9 #define SkPixelRef_DEFINED 10 11 #include "../private/SkAtomics.h" 12 #include "../private/SkMutex.h" 13 #include "../private/SkTDArray.h" 14 #include "SkBitmap.h" 15 #include "SkFilterQuality.h" 16 #include "SkImageInfo.h" 17 #include "SkPixmap.h" 18 #include "SkRefCnt.h" 19 #include "SkSize.h" 20 #include "SkString.h" 21 22 #ifdef SK_SUPPORT_LEGACY_COLORTABLE 23 class SkColorTable; 24 #endif 25 struct SkIRect; 26 27 class GrTexture; 28 class SkDiscardableMemory; 29 30 /** \class SkPixelRef 31 32 This class is the smart container for pixel memory, and is used with SkBitmap. 33 This class can be shared/accessed between multiple threads. 34 */ 35 class SK_API SkPixelRef : public SkRefCnt { 36 public: 37 SkPixelRef(int width, int height, void* addr, size_t rowBytes); 38 ~SkPixelRef() override; 39 40 int width() const { return fWidth; } 41 int height() const { return fHeight; } 42 void* pixels() const { return fPixels; } 43 size_t rowBytes() const { return fRowBytes; } 44 45 /** Returns a non-zero, unique value corresponding to the pixels in this 46 pixelref. Each time the pixels are changed (and notifyPixelsChanged is 47 called), a different generation ID will be returned. 48 */ 49 uint32_t getGenerationID() const; 50 51 #ifdef SK_BUILD_FOR_ANDROID_FRAMEWORK 52 /** Returns a non-zero, unique value corresponding to this SkPixelRef. 53 Unlike the generation ID, this ID remains the same even when the pixels 54 are changed. IDs are not reused (until uint32_t wraps), so it is safe 55 to consider this ID unique even after this SkPixelRef is deleted. 56 57 Can be used as a key which uniquely identifies this SkPixelRef 58 regardless of changes to its pixels or deletion of this object. 59 */ 60 uint32_t getStableID() const { return fStableID; } 61 #endif 62 63 /** 64 * Call this if you have changed the contents of the pixels. This will in- 65 * turn cause a different generation ID value to be returned from 66 * getGenerationID(). 67 */ 68 void notifyPixelsChanged(); 69 70 /** Returns true if this pixelref is marked as immutable, meaning that the 71 contents of its pixels will not change for the lifetime of the pixelref. 72 */ 73 bool isImmutable() const { return fMutability != kMutable; } 74 75 /** Marks this pixelref is immutable, meaning that the contents of its 76 pixels will not change for the lifetime of the pixelref. This state can 77 be set on a pixelref, but it cannot be cleared once it is set. 78 */ 79 void setImmutable(); 80 81 // Register a listener that may be called the next time our generation ID changes. 82 // 83 // We'll only call the listener if we're confident that we are the only SkPixelRef with this 84 // generation ID. If our generation ID changes and we decide not to call the listener, we'll 85 // never call it: you must add a new listener for each generation ID change. We also won't call 86 // the listener when we're certain no one knows what our generation ID is. 87 // 88 // This can be used to invalidate caches keyed by SkPixelRef generation ID. 89 struct GenIDChangeListener { 90 virtual ~GenIDChangeListener() {} 91 virtual void onChange() = 0; 92 }; 93 94 // Takes ownership of listener. 95 void addGenIDChangeListener(GenIDChangeListener* listener); 96 97 // Call when this pixelref is part of the key to a resourcecache entry. This allows the cache 98 // to know automatically those entries can be purged when this pixelref is changed or deleted. 99 void notifyAddedToCache() { 100 fAddedToCache.store(true); 101 } 102 103 virtual SkDiscardableMemory* diagnostic_only_getDiscardable() const { return NULL; } 104 105 #ifdef SK_SUPPORT_LEGACY_COLORTABLE 106 SkPixelRef(int width, int height, void* addr, size_t rowBytes, sk_sp<SkColorTable>); 107 SkColorTable* colorTable() const { return nullptr; } 108 #endif 109 protected: 110 // default impl does nothing. 111 virtual void onNotifyPixelsChanged(); 112 113 #ifdef SK_SUPPORT_LEGACY_COLORTABLE 114 void android_only_reset(int width, int height, size_t rowBytes, sk_sp<SkColorTable>); 115 #else 116 void android_only_reset(int width, int height, size_t rowBytes); 117 #endif 118 119 private: 120 int fWidth; 121 int fHeight; 122 void* fPixels; 123 size_t fRowBytes; 124 125 // Bottom bit indicates the Gen ID is unique. 126 bool genIDIsUnique() const { return SkToBool(fTaggedGenID.load() & 1); } 127 mutable SkAtomic<uint32_t> fTaggedGenID; 128 129 #ifdef SK_BUILD_FOR_ANDROID_FRAMEWORK 130 const uint32_t fStableID; 131 #endif 132 133 SkTDArray<GenIDChangeListener*> fGenIDChangeListeners; // pointers are owned 134 135 // Set true by caches when they cache content that's derived from the current pixels. 136 SkAtomic<bool> fAddedToCache; 137 138 enum { 139 kMutable, // PixelRefs begin mutable. 140 kTemporarilyImmutable, // Considered immutable, but can revert to mutable. 141 kImmutable, // Once set to this state, it never leaves. 142 } fMutability : 8; // easily fits inside a byte 143 144 void needsNewGenID(); 145 void callGenIDChangeListeners(); 146 147 void setTemporarilyImmutable(); 148 void restoreMutability(); 149 friend class SkSurface_Raster; // For the two methods above. 150 151 friend class SkImage_Raster; 152 friend class SkSpecialImage_Raster; 153 154 void setImmutableWithID(uint32_t genID); 155 friend class SkImage_Gpu; 156 friend class SkImage_Lazy; 157 friend class SkSpecialImage_Gpu; 158 friend void SkBitmapCache_setImmutableWithID(SkPixelRef*, uint32_t); 159 160 typedef SkRefCnt INHERITED; 161 }; 162 163 #endif 164
