gfx/thebes/public/gfxTextRunCache.h

   1 /* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 4 -*-
   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
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   8  * http://www.mozilla.org/MPL/
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  14  *
  15  * The Original Code is Mozilla Foundation code.
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  17  * The Initial Developer of the Original Code is Mozilla Foundation.
  18  * Portions created by the Initial Developer are Copyright (C) 2006
  19  * the Initial Developer. All Rights Reserved.
  20  *
  21  * Contributor(s):
  22  *   Vladimir Vukicevic <vladimir@pobox.com>
  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"),
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  36  * ***** END LICENSE BLOCK ***** */
  37
  38 #ifndef GFX_TEXT_RUN_CACHE_H
  39 #define GFX_TEXT_RUN_CACHE_H
  40
  41 #include "gfxFont.h"
  42
  43 /**
  44  * A simple textrun cache for textruns that do not carry state
  45  * (e.g., actual or potential linebreaks) and do not need complex initialization.
  46  * The lifetimes of these textruns are managed by the cache (they are auto-expired
  47  * after a certain period of time).
  48  */
  49 class THEBES_API gfxTextRunCache {
  50 public:
  51     /**
  52      * Get a textrun for the given text, using a global cache. The textrun
  53      * must be released via ReleaseTextRun, not deleted.
  54      * Do not set any state in the textrun (e.g. actual or potential linebreaks).
  55      * Flags IS_8BIT, IS_ASCII and HAS_SURROGATES are automatically set
  56      * appropriately.
  57      * Flag IS_PERSISTENT must NOT be set unless aText is guaranteed to live
  58      * forever.
  59      * The string can contain any characters, invalid ones will be stripped
  60      * properly.
  61      */
  62     static gfxTextRun *MakeTextRun(const PRUnichar *aText, PRUint32 aLength,
  63                                    gfxFontGroup *aFontGroup,
  64                                    gfxContext *aRefContext,
  65                                    PRUint32 aAppUnitsPerDevUnit,
  66                                    PRUint32 aFlags);
  67
  68     /**
  69      * As above, but allows a full Parameters object to be passed in.
  70      */
  71     static gfxTextRun *MakeTextRun(const PRUnichar *aText, PRUint32 aLength,
  72                                    gfxFontGroup *aFontGroup,
  73                                    const gfxTextRunFactory::Parameters* aParams,
  74                                    PRUint32 aFlags);
  75
  76     /**
  77      * Get a textrun for the given text, using a global cache. The textrun
  78      * must be released via ReleaseTextRun, not deleted.
  79      * Do not set any state in the textrun (e.g. actual or potential linebreaks).
  80      * Flags IS_8BIT, IS_ASCII and HAS_SURROGATES are automatically set
  81      * appropriately.
  82      * Flag IS_PERSISTENT must NOT be set unless aText is guaranteed to live
  83      * forever.
  84      * The string can contain any characters, invalid ones will be stripped
  85      * properly.
  86      */
  87     static gfxTextRun *MakeTextRun(const PRUint8 *aText, PRUint32 aLength,
  88                                    gfxFontGroup *aFontGroup,
  89                                    gfxContext *aRefContext,
  90                                    PRUint32 aAppUnitsPerDevUnit,
  91                                    PRUint32 aFlags);
  92
  93     /**
  94      * Release a previously acquired textrun. Consider using AutoTextRun
  95      * instead of calling this.
  96      */
  97     static void ReleaseTextRun(gfxTextRun *aTextRun);
  98
  99     class AutoTextRun {
 100     public:
 101         AutoTextRun(gfxTextRun *aTextRun) : mTextRun(aTextRun) {}
 102         AutoTextRun() : mTextRun(nsnull) {}
 103         AutoTextRun& operator=(gfxTextRun *aTextRun) {
 104             gfxTextRunCache::ReleaseTextRun(mTextRun);
 105             mTextRun = aTextRun;
 106             return *this;
 107         }
 108         ~AutoTextRun() {
 109             gfxTextRunCache::ReleaseTextRun(mTextRun);
 110         }
 111         gfxTextRun *get() { return mTextRun; }
 112         gfxTextRun *operator->() { return mTextRun; }
 113     private:
 114         gfxTextRun *mTextRun;
 115     };
 116
 117 protected:
 118     friend class gfxPlatform;
 119
 120     static nsresult Init();
 121     static void Shutdown();
 122 };
 123
 124 #endif /* GFX_TEXT_RUN_CACHE_H */