1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/gfx/thebes/gfxCachedTempSurface.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,58 @@
1.4 +/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*-
1.5 + * This Source Code Form is subject to the terms of the Mozilla Public
1.6 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.7 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.8 +
1.9 +#ifndef GFX_CACHED_TEMP_SURFACE_H
1.10 +#define GFX_CACHED_TEMP_SURFACE_H
1.11 +
1.12 +#include "gfxASurface.h"
1.13 +#include "nsExpirationTracker.h"
1.14 +#include "nsSize.h"
1.15 +
1.16 +class gfxContext;
1.17 +
1.18 +/**
1.19 + * This class can be used to cache double-buffering back surfaces.
1.20 + *
1.21 + * Large resource allocations may have an overhead that can be avoided by
1.22 + * caching. Caching also alows the system to use history in deciding whether
1.23 + * to manage the surfaces in video or system memory.
1.24 + *
1.25 + * However, because we don't want to set aside megabytes of unused resources
1.26 + * unncessarily, these surfaces are released on a timer.
1.27 + */
1.28 +
1.29 +class gfxCachedTempSurface {
1.30 +public:
1.31 + /**
1.32 + * Returns a context for a surface that can be efficiently copied to
1.33 + * |aSimilarTo|.
1.34 + *
1.35 + * When |aContentType| has an alpha component, the surface will be cleared.
1.36 + * For opaque surfaces, the initial surface contents are undefined.
1.37 + * When |aContentType| differs in different invocations this is handled
1.38 + * appropriately, creating a new surface if necessary.
1.39 + *
1.40 + * Because the cached surface may have been created during a previous
1.41 + * invocation, this will not be efficient if the new |aSimilarTo| has a
1.42 + * different format, size, or gfxSurfaceType.
1.43 + */
1.44 + already_AddRefed<gfxContext> Get(gfxContentType aContentType,
1.45 + const gfxRect& aRect,
1.46 + gfxASurface* aSimilarTo);
1.47 +
1.48 + void Expire() { mSurface = nullptr; }
1.49 + nsExpirationState* GetExpirationState() { return &mExpirationState; }
1.50 + ~gfxCachedTempSurface();
1.51 +
1.52 + bool IsSurface(gfxASurface* aSurface) { return mSurface == aSurface; }
1.53 +
1.54 +private:
1.55 + nsRefPtr<gfxASurface> mSurface;
1.56 + gfxIntSize mSize;
1.57 + nsExpirationState mExpirationState;
1.58 + gfxSurfaceType mType;
1.59 +};
1.60 +
1.61 +#endif /* GFX_CACHED_TEMP_SURFACE_H */
