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comparison: gfx/thebes/gfxCachedTempSurface.h
gfx/thebes/gfxCachedTempSurface.h
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| 1 /* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*- | |
| 2 * This Source Code Form is subject to the terms of the Mozilla Public | |
| 3 * License, v. 2.0. If a copy of the MPL was not distributed with this | |
| 4 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ | |
| 5 | |
| 6 #ifndef GFX_CACHED_TEMP_SURFACE_H | |
| 7 #define GFX_CACHED_TEMP_SURFACE_H | |
| 8 | |
| 9 #include "gfxASurface.h" | |
| 10 #include "nsExpirationTracker.h" | |
| 11 #include "nsSize.h" | |
| 12 | |
| 13 class gfxContext; | |
| 14 | |
| 15 /** | |
| 16 * This class can be used to cache double-buffering back surfaces. | |
| 17 * | |
| 18 * Large resource allocations may have an overhead that can be avoided by | |
| 19 * caching. Caching also alows the system to use history in deciding whether | |
| 20 * to manage the surfaces in video or system memory. | |
| 21 * | |
| 22 * However, because we don't want to set aside megabytes of unused resources | |
| 23 * unncessarily, these surfaces are released on a timer. | |
| 24 */ | |
| 25 | |
| 26 class gfxCachedTempSurface { | |
| 27 public: | |
| 28 /** | |
| 29 * Returns a context for a surface that can be efficiently copied to | |
| 30 * |aSimilarTo|. | |
| 31 * | |
| 32 * When |aContentType| has an alpha component, the surface will be cleared. | |
| 33 * For opaque surfaces, the initial surface contents are undefined. | |
| 34 * When |aContentType| differs in different invocations this is handled | |
| 35 * appropriately, creating a new surface if necessary. | |
| 36 * | |
| 37 * Because the cached surface may have been created during a previous | |
| 38 * invocation, this will not be efficient if the new |aSimilarTo| has a | |
| 39 * different format, size, or gfxSurfaceType. | |
| 40 */ | |
| 41 already_AddRefed<gfxContext> Get(gfxContentType aContentType, | |
| 42 const gfxRect& aRect, | |
| 43 gfxASurface* aSimilarTo); | |
| 44 | |
| 45 void Expire() { mSurface = nullptr; } | |
| 46 nsExpirationState* GetExpirationState() { return &mExpirationState; } | |
| 47 ~gfxCachedTempSurface(); | |
| 48 | |
| 49 bool IsSurface(gfxASurface* aSurface) { return mSurface == aSurface; } | |
| 50 | |
| 51 private: | |
| 52 nsRefPtr<gfxASurface> mSurface; | |
| 53 gfxIntSize mSize; | |
| 54 nsExpirationState mExpirationState; | |
| 55 gfxSurfaceType mType; | |
| 56 }; | |
| 57 | |
| 58 #endif /* GFX_CACHED_TEMP_SURFACE_H */ |
