1 : /* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*-
2 : * ***** BEGIN LICENSE BLOCK *****
3 : * Version: MPL 1.1/GPL 2.0/LGPL 2.1
4 : *
5 : * The contents of this file are subject to the Mozilla Public License Version
6 : * 1.1 (the "License"); you may not use this file except in compliance with
7 : * the License. You may obtain a copy of the License at
8 : * http://www.mozilla.org/MPL/
9 : *
10 : * Software distributed under the License is distributed on an "AS IS" basis,
11 : * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
12 : * for the specific language governing rights and limitations under the
13 : * License.
14 : *
15 : * The Original Code is Mozilla Corporation code.
16 : *
17 : * The Initial Developer of the Original Code is Mozilla Foundation.
18 : * Portions created by the Initial Developer are Copyright (C) 2009
19 : * the Initial Developer. All Rights Reserved.
20 : *
21 : * Contributor(s):
22 : * Karl Tomlinson <karlt+@karlt.net>
23 : *
24 : * Alternatively, the contents of this file may be used under the terms of
25 : * either the GNU General Public License Version 2 or later (the "GPL"), or
26 : * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
27 : * in which case the provisions of the GPL or the LGPL are applicable instead
28 : * of those above. If you wish to allow use of your version of this file only
29 : * under the terms of either the GPL or the LGPL, and not to allow others to
30 : * use your version of this file under the terms of the MPL, indicate your
31 : * decision by deleting the provisions above and replace them with the notice
32 : * and other provisions required by the GPL or the LGPL. If you do not delete
33 : * the provisions above, a recipient may use your version of this file under
34 : * the terms of any one of the MPL, the GPL or the LGPL.
35 : *
36 : * ***** END LICENSE BLOCK ***** */
37 :
38 : #ifndef GFX_CACHED_TEMP_SURFACE_H
39 : #define GFX_CACHED_TEMP_SURFACE_H
40 :
41 : #include "gfxASurface.h"
42 : #include "nsExpirationTracker.h"
43 :
44 : class gfxContext;
45 :
46 : /**
47 : * This class can be used to cache double-buffering back surfaces.
48 : *
49 : * Large resource allocations may have an overhead that can be avoided by
50 : * caching. Caching also alows the system to use history in deciding whether
51 : * to manage the surfaces in video or system memory.
52 : *
53 : * However, because we don't want to set aside megabytes of unused resources
54 : * unncessarily, these surfaces are released on a timer.
55 : */
56 :
57 : class THEBES_API gfxCachedTempSurface {
58 : public:
59 : /**
60 : * Returns a context for a surface that can be efficiently copied to
61 : * |aSimilarTo|.
62 : *
63 : * When |aContentType| has an alpha component, the surface will be cleared.
64 : * For opaque surfaces, the initial surface contents are undefined.
65 : * When |aContentType| differs in different invocations this is handled
66 : * appropriately, creating a new surface if necessary.
67 : *
68 : * |aSimilarTo| should be of the same gfxSurfaceType in each invocation.
69 : * Because the cached surface may have been created during a previous
70 : * invocation, this will not be efficient if the new |aSimilarTo| has a
71 : * different format.
72 : */
73 : already_AddRefed<gfxContext> Get(gfxASurface::gfxContentType aContentType,
74 : const gfxRect& aRect,
75 : gfxASurface* aSimilarTo);
76 :
77 0 : void Expire() { mSurface = nsnull; }
78 0 : nsExpirationState* GetExpirationState() { return &mExpirationState; }
79 : ~gfxCachedTempSurface();
80 :
81 : bool IsSurface(gfxASurface* aSurface) { return mSurface == aSurface; }
82 :
83 : private:
84 : nsRefPtr<gfxASurface> mSurface;
85 : gfxIntSize mSize;
86 : nsExpirationState mExpirationState;
87 : #ifdef DEBUG
88 : gfxASurface::gfxSurfaceType mType;
89 : #endif
90 : };
91 :
92 : #endif /* GFX_CACHED_TEMP_SURFACE_H */
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