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 "include/core/SkBitmap.h" 12#include "include/core/SkImageInfo.h" 13#include "include/core/SkPixmap.h" 14#include "include/core/SkRefCnt.h" 15#include "include/core/SkSize.h" 16#include "include/private/SkIDChangeListener.h" 17#include "include/private/SkMutex.h" 18#include "include/private/SkTDArray.h" 19 20#include <atomic> 21 22struct SkIRect; 23 24class GrTexture; 25class SkDiscardableMemory; 26 27/** \class SkPixelRef 28 29 This class is the smart container for pixel memory, and is used with SkBitmap. 30 This class can be shared/accessed between multiple threads. 31*/ 32class SK_API SkPixelRef : public SkRefCnt { 33public: 34 SkPixelRef(int width, int height, void* addr, size_t rowBytes); 35 ~SkPixelRef() override; 36 37 SkISize dimensions() const { return {fWidth, fHeight}; } 38 int width() const { return fWidth; } 39 int height() const { return fHeight; } 40 void* pixels() const { return fPixels; } 41 size_t rowBytes() const { return fRowBytes; } 42 43 /** Returns a non-zero, unique value corresponding to the pixels in this 44 pixelref. Each time the pixels are changed (and notifyPixelsChanged is 45 called), a different generation ID will be returned. 46 */ 47 uint32_t getGenerationID() const; 48 49 /** 50 * Call this if you have changed the contents of the pixels. This will in- 51 * turn cause a different generation ID value to be returned from 52 * getGenerationID(). 53 */ 54 void notifyPixelsChanged(); 55 56 /** Returns true if this pixelref is marked as immutable, meaning that the 57 contents of its pixels will not change for the lifetime of the pixelref. 58 */ 59 bool isImmutable() const { return fMutability != kMutable; } 60 61 /** Marks this pixelref is immutable, meaning that the contents of its 62 pixels will not change for the lifetime of the pixelref. This state can 63 be set on a pixelref, but it cannot be cleared once it is set. 64 */ 65 void setImmutable(); 66 67 // Register a listener that may be called the next time our generation ID changes. 68 // 69 // We'll only call the listener if we're confident that we are the only SkPixelRef with this 70 // generation ID. If our generation ID changes and we decide not to call the listener, we'll 71 // never call it: you must add a new listener for each generation ID change. We also won't call 72 // the listener when we're certain no one knows what our generation ID is. 73 // 74 // This can be used to invalidate caches keyed by SkPixelRef generation ID. 75 // Takes ownership of listener. Threadsafe. 76 void addGenIDChangeListener(sk_sp<SkIDChangeListener> listener); 77 78 // Call when this pixelref is part of the key to a resourcecache entry. This allows the cache 79 // to know automatically those entries can be purged when this pixelref is changed or deleted. 80 void notifyAddedToCache() { 81 fAddedToCache.store(true); 82 } 83 84 virtual SkDiscardableMemory* diagnostic_only_getDiscardable() const { return nullptr; } 85 86protected: 87 void android_only_reset(int width, int height, size_t rowBytes); 88 89private: 90 int fWidth; 91 int fHeight; 92 void* fPixels; 93 size_t fRowBytes; 94 95 // Bottom bit indicates the Gen ID is unique. 96 bool genIDIsUnique() const { return SkToBool(fTaggedGenID.load() & 1); } 97 mutable std::atomic<uint32_t> fTaggedGenID; 98 99 SkIDChangeListener::List fGenIDChangeListeners; 100 101 // Set true by caches when they cache content that's derived from the current pixels. 102 std::atomic<bool> fAddedToCache; 103 104 enum Mutability { 105 kMutable, // PixelRefs begin mutable. 106 kTemporarilyImmutable, // Considered immutable, but can revert to mutable. 107 kImmutable, // Once set to this state, it never leaves. 108 } fMutability : 8; // easily fits inside a byte 109 110 void needsNewGenID(); 111 void callGenIDChangeListeners(); 112 113 void setTemporarilyImmutable(); 114 void restoreMutability(); 115 friend class SkSurface_Raster; // For the two methods above. 116 117 void setImmutableWithID(uint32_t genID); 118 friend void SkBitmapCache_setImmutableWithID(SkPixelRef*, uint32_t); 119 120 using INHERITED = SkRefCnt; 121}; 122 123#endif 124