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1 /*
2  *
3  * (C) Copyright IBM Corp. 1998-2007 - All Rights Reserved
4  *
5  * Developed at DIT - Government of Bhutan
6  *
7  * Contact person: Pema Geyleg - <pema_geyleg@druknet.bt>
8  *
9  * This file is a modification of the ICU file KhmerReordering.cpp
10  * by Jens Herden and Javier Sola who have given all their possible rights to IBM and the Governement of Bhutan
11  * A first module for Dzongkha was developed by Karunakar under Panlocalisation funding.
12  * Assistance for this module has been received from Namgay Thinley, Christopher Fynn and Javier Sola
13  *
14  */
15 
16 #ifndef __TIBETANLAYOUTENGINE_H
17 #define __TIBETANLAYOUTENGINE_H
18 
19 // #include "LETypes.h"
20 // #include "LEFontInstance.h"
21 // #include "LEGlyphFilter.h"
22 // #include "LayoutEngine.h"
23 // #include "OpenTypeLayoutEngine.h"
24 
25 // #include "GlyphSubstitutionTables.h"
26 // #include "GlyphDefinitionTables.h"
27 // #include "GlyphPositioningTables.h"
28 
29 U_NAMESPACE_BEGIN
30 
31 // class MPreFixups;
32 // class LEGlyphStorage;
33 
34 /**
35  * This class implements OpenType layout for Dzongkha and Tibetan OpenType fonts
36  *
37  * @internal
38  */
39 class TibetanOpenTypeLayoutEngine : public OpenTypeLayoutEngine
40 {
41 public:
42     /**
43      * This is the main constructor. It constructs an instance of TibetanOpenTypeLayoutEngine for
44      * a particular font, script and language. It takes the GSUB table as a parameter since
45      * LayoutEngine::layoutEngineFactory has to read the GSUB table to know that it has an
46      * Tibetan OpenType font.
47      *
48      * @param fontInstance - the font
49      * @param scriptCode - the script
50      * @param langaugeCode - the language
51      * @param gsubTable - the GSUB table
52      *
53      * @see LayoutEngine::layoutEngineFactory
54      * @see OpenTypeLayoutEngine
55      * @see ScriptAndLangaugeTags.h for script and language codes
56      *
57      * @internal
58      */
59     TibetanOpenTypeLayoutEngine(const LEFontInstance *fontInstance, le_int32 scriptCode, le_int32 languageCode,
60                             le_int32 typoFlags, const GlyphSubstitutionTableHeader *gsubTable);
61 
62     /**
63      * This constructor is used when the font requires a "canned" GSUB table which can't be known
64      * until after this constructor has been invoked.
65      *
66      * @param fontInstance - the font
67      * @param scriptCode - the script
68      * @param langaugeCode - the language
69      *
70      * @see OpenTypeLayoutEngine
71      * @see ScriptAndLangaugeTags.h for script and language codes
72      *
73      * @internal
74      */
75     TibetanOpenTypeLayoutEngine(const LEFontInstance *fontInstance, le_int32 scriptCode, le_int32 languageCode,
76                                 le_int32 typoFlags);
77 
78     /**
79      * The destructor, virtual for correct polymorphic invocation.
80      *
81      * @internal
82      */
83    virtual ~TibetanOpenTypeLayoutEngine();
84 
85     /**
86      * ICU "poor man's RTTI", returns a UClassID for the actual class.
87      *
88      * @internal ICU 3.6
89      */
90     virtual UClassID getDynamicClassID() const;
91 
92     /**
93      * ICU "poor man's RTTI", returns a UClassID for this class.
94      *
95      * @internal ICU 3.6
96      */
97     static UClassID getStaticClassID();
98 
99 protected:
100 
101     /**
102      * This method does Tibetan OpenType character processing. It assigns the OpenType feature
103      * tags to the characters, and may generate output characters which have been reordered.
104      * It may also split some vowels, resulting in more output characters than input characters.
105      *
106      * Input parameters:
107      * @param chars - the input character context
108      * @param offset - the index of the first character to process
109      * @param count - the number of characters to process
110      * @param max - the number of characters in the input context
111      * @param rightToLeft - <code>TRUE</code> if the characters are in a right to left directional run
112      * @param glyphStorage - the glyph storage object. The glyph and character index arrays will be set.
113      *                       the auxillary data array will be set to the feature tags.
114      *
115      * Output parameters:
116      * @param success - set to an error code if the operation fails
117      *
118      * @return the output character count
119      *
120      * @internal
121      */
122     virtual le_int32 characterProcessing(const LEUnicode chars[], le_int32 offset, le_int32 count, le_int32 max, le_bool rightToLeft,
123             LEUnicode *&outChars, LEGlyphStorage &glyphStorage, LEErrorCode &success);
124 
125 };
126 
127 U_NAMESPACE_END
128 #endif
129 
130