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- /*
- * Copyright 2008 The Android Open Source Project
- *
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
- #ifndef SkPixelRef_DEFINED
- #define SkPixelRef_DEFINED
- #include "include/core/SkBitmap.h"
- #include "include/core/SkFilterQuality.h"
- #include "include/core/SkImageInfo.h"
- #include "include/core/SkPixmap.h"
- #include "include/core/SkRefCnt.h"
- #include "include/core/SkSize.h"
- #include "include/core/SkString.h"
- #include "include/private/SkMutex.h"
- #include "include/private/SkTDArray.h"
- #include <atomic>
- struct SkIRect;
- class GrTexture;
- class SkDiscardableMemory;
- /** \class SkPixelRef
- This class is the smart container for pixel memory, and is used with SkBitmap.
- This class can be shared/accessed between multiple threads.
- */
- class SK_API SkPixelRef : public SkRefCnt {
- public:
- SkPixelRef(int width, int height, void* addr, size_t rowBytes);
- ~SkPixelRef() override;
- int width() const { return fWidth; }
- int height() const { return fHeight; }
- void* pixels() const { return fPixels; }
- size_t rowBytes() const { return fRowBytes; }
- /** Returns a non-zero, unique value corresponding to the pixels in this
- pixelref. Each time the pixels are changed (and notifyPixelsChanged is
- called), a different generation ID will be returned.
- */
- uint32_t getGenerationID() const;
- /**
- * Call this if you have changed the contents of the pixels. This will in-
- * turn cause a different generation ID value to be returned from
- * getGenerationID().
- */
- void notifyPixelsChanged();
- /** Returns true if this pixelref is marked as immutable, meaning that the
- contents of its pixels will not change for the lifetime of the pixelref.
- */
- bool isImmutable() const { return fMutability != kMutable; }
- /** Marks this pixelref is immutable, meaning that the contents of its
- pixels will not change for the lifetime of the pixelref. This state can
- be set on a pixelref, but it cannot be cleared once it is set.
- */
- void setImmutable();
- // Register a listener that may be called the next time our generation ID changes.
- //
- // We'll only call the listener if we're confident that we are the only SkPixelRef with this
- // generation ID. If our generation ID changes and we decide not to call the listener, we'll
- // never call it: you must add a new listener for each generation ID change. We also won't call
- // the listener when we're certain no one knows what our generation ID is.
- //
- // This can be used to invalidate caches keyed by SkPixelRef generation ID.
- struct GenIDChangeListener {
- virtual ~GenIDChangeListener() {}
- virtual void onChange() = 0;
- };
- // Takes ownership of listener. Threadsafe.
- void addGenIDChangeListener(GenIDChangeListener* listener);
- // Call when this pixelref is part of the key to a resourcecache entry. This allows the cache
- // to know automatically those entries can be purged when this pixelref is changed or deleted.
- void notifyAddedToCache() {
- fAddedToCache.store(true);
- }
- virtual SkDiscardableMemory* diagnostic_only_getDiscardable() const { return nullptr; }
- protected:
- void android_only_reset(int width, int height, size_t rowBytes);
- private:
- int fWidth;
- int fHeight;
- void* fPixels;
- size_t fRowBytes;
- // Bottom bit indicates the Gen ID is unique.
- bool genIDIsUnique() const { return SkToBool(fTaggedGenID.load() & 1); }
- mutable std::atomic<uint32_t> fTaggedGenID;
- SkMutex fGenIDChangeListenersMutex;
- SkTDArray<GenIDChangeListener*> fGenIDChangeListeners; // pointers are owned
- // Set true by caches when they cache content that's derived from the current pixels.
- std::atomic<bool> fAddedToCache;
- enum Mutability {
- kMutable, // PixelRefs begin mutable.
- kTemporarilyImmutable, // Considered immutable, but can revert to mutable.
- kImmutable, // Once set to this state, it never leaves.
- } fMutability : 8; // easily fits inside a byte
- void needsNewGenID();
- void callGenIDChangeListeners();
- void setTemporarilyImmutable();
- void restoreMutability();
- friend class SkSurface_Raster; // For the two methods above.
- void setImmutableWithID(uint32_t genID);
- friend void SkBitmapCache_setImmutableWithID(SkPixelRef*, uint32_t);
- typedef SkRefCnt INHERITED;
- };
- #endif
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