gfx/thebes/gfxCachedTempSurface.h@b8a032363ba2 (annotated)
gfx/thebes/gfxCachedTempSurface.h
Thu, 22 Jan 2015 13:21:57 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Thu, 22 Jan 2015 13:21:57 +0100
- branch
- TOR_BUG_9701
- changeset 15
- b8a032363ba2
- permissions
- -rw-r--r--
Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6
| michael@0 | 1 | /* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*- |
| michael@0 | 2 | * This Source Code Form is subject to the terms of the Mozilla Public |
| michael@0 | 3 | * License, v. 2.0. If a copy of the MPL was not distributed with this |
| michael@0 | 4 | * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ |
| michael@0 | 5 | |
| michael@0 | 6 | #ifndef GFX_CACHED_TEMP_SURFACE_H |
| michael@0 | 7 | #define GFX_CACHED_TEMP_SURFACE_H |
| michael@0 | 8 | |
| michael@0 | 9 | #include "gfxASurface.h" |
| michael@0 | 10 | #include "nsExpirationTracker.h" |
| michael@0 | 11 | #include "nsSize.h" |
| michael@0 | 12 | |
| michael@0 | 13 | class gfxContext; |
| michael@0 | 14 | |
| michael@0 | 15 | /** |
| michael@0 | 16 | * This class can be used to cache double-buffering back surfaces. |
| michael@0 | 17 | * |
| michael@0 | 18 | * Large resource allocations may have an overhead that can be avoided by |
| michael@0 | 19 | * caching. Caching also alows the system to use history in deciding whether |
| michael@0 | 20 | * to manage the surfaces in video or system memory. |
| michael@0 | 21 | * |
| michael@0 | 22 | * However, because we don't want to set aside megabytes of unused resources |
| michael@0 | 23 | * unncessarily, these surfaces are released on a timer. |
| michael@0 | 24 | */ |
| michael@0 | 25 | |
| michael@0 | 26 | class gfxCachedTempSurface { |
| michael@0 | 27 | public: |
| michael@0 | 28 | /** |
| michael@0 | 29 | * Returns a context for a surface that can be efficiently copied to |
| michael@0 | 30 | * |aSimilarTo|. |
| michael@0 | 31 | * |
| michael@0 | 32 | * When |aContentType| has an alpha component, the surface will be cleared. |
| michael@0 | 33 | * For opaque surfaces, the initial surface contents are undefined. |
| michael@0 | 34 | * When |aContentType| differs in different invocations this is handled |
| michael@0 | 35 | * appropriately, creating a new surface if necessary. |
| michael@0 | 36 | * |
| michael@0 | 37 | * Because the cached surface may have been created during a previous |
| michael@0 | 38 | * invocation, this will not be efficient if the new |aSimilarTo| has a |
| michael@0 | 39 | * different format, size, or gfxSurfaceType. |
| michael@0 | 40 | */ |
| michael@0 | 41 | already_AddRefed<gfxContext> Get(gfxContentType aContentType, |
| michael@0 | 42 | const gfxRect& aRect, |
| michael@0 | 43 | gfxASurface* aSimilarTo); |
| michael@0 | 44 | |
| michael@0 | 45 | void Expire() { mSurface = nullptr; } |
| michael@0 | 46 | nsExpirationState* GetExpirationState() { return &mExpirationState; } |
| michael@0 | 47 | ~gfxCachedTempSurface(); |
| michael@0 | 48 | |
| michael@0 | 49 | bool IsSurface(gfxASurface* aSurface) { return mSurface == aSurface; } |
| michael@0 | 50 | |
| michael@0 | 51 | private: |
| michael@0 | 52 | nsRefPtr<gfxASurface> mSurface; |
| michael@0 | 53 | gfxIntSize mSize; |
| michael@0 | 54 | nsExpirationState mExpirationState; |
| michael@0 | 55 | gfxSurfaceType mType; |
| michael@0 | 56 | }; |
| michael@0 | 57 | |
| michael@0 | 58 | #endif /* GFX_CACHED_TEMP_SURFACE_H */ |
