зеркало из https://github.com/mozilla/gecko-dev.git
61 строка
2.1 KiB
C++
61 строка
2.1 KiB
C++
/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*-
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#ifndef GFX_CACHED_TEMP_SURFACE_H
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#define GFX_CACHED_TEMP_SURFACE_H
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#include "gfxASurface.h"
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#include "nsExpirationTracker.h"
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class gfxContext;
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/**
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* This class can be used to cache double-buffering back surfaces.
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*
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* Large resource allocations may have an overhead that can be avoided by
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* caching. Caching also alows the system to use history in deciding whether
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* to manage the surfaces in video or system memory.
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*
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* However, because we don't want to set aside megabytes of unused resources
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* unncessarily, these surfaces are released on a timer.
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*/
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class gfxCachedTempSurface {
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public:
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/**
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* Returns a context for a surface that can be efficiently copied to
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* |aSimilarTo|.
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*
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* When |aContentType| has an alpha component, the surface will be cleared.
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* For opaque surfaces, the initial surface contents are undefined.
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* When |aContentType| differs in different invocations this is handled
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* appropriately, creating a new surface if necessary.
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*
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* |aSimilarTo| should be of the same gfxSurfaceType in each invocation.
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* Because the cached surface may have been created during a previous
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* invocation, this will not be efficient if the new |aSimilarTo| has a
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* different format.
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*/
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already_AddRefed<gfxContext> Get(gfxASurface::gfxContentType aContentType,
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const gfxRect& aRect,
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gfxASurface* aSimilarTo);
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void Expire() { mSurface = nullptr; }
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nsExpirationState* GetExpirationState() { return &mExpirationState; }
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~gfxCachedTempSurface();
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bool IsSurface(gfxASurface* aSurface) { return mSurface == aSurface; }
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private:
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nsRefPtr<gfxASurface> mSurface;
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gfxIntSize mSize;
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nsExpirationState mExpirationState;
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#ifdef DEBUG
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gfxASurface::gfxSurfaceType mType;
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#endif
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};
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#endif /* GFX_CACHED_TEMP_SURFACE_H */
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