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1 /*
2  *
3  * (C) Copyright IBM Corp. 1998-2008 - 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      * @param success - set to an error code if the operation fails
53      *
54      * @see LayoutEngine::layoutEngineFactory
55      * @see OpenTypeLayoutEngine
56      * @see ScriptAndLangaugeTags.h for script and language codes
57      *
58      * @internal
59      */
60     TibetanOpenTypeLayoutEngine(const LEFontInstance *fontInstance, le_int32 scriptCode, le_int32 languageCode,
61                             le_int32 typoFlags, const GlyphSubstitutionTableHeader *gsubTable, LEErrorCode &success);
62 
63     /**
64      * This constructor is used when the font requires a "canned" GSUB table which can't be known
65      * until after this constructor has been invoked.
66      *
67      * @param fontInstance - the font
68      * @param scriptCode - the script
69      * @param langaugeCode - the language
70      * @param success - set to an error code if the operation fails
71      *
72      * @see OpenTypeLayoutEngine
73      * @see ScriptAndLangaugeTags.h for script and language codes
74      *
75      * @internal
76      */
77     TibetanOpenTypeLayoutEngine(const LEFontInstance *fontInstance, le_int32 scriptCode, le_int32 languageCode,
78                                 le_int32 typoFlags, LEErrorCode &success);
79 
80     /**
81      * The destructor, virtual for correct polymorphic invocation.
82      *
83      * @internal
84      */
85    virtual ~TibetanOpenTypeLayoutEngine();
86 
87     /**
88      * ICU "poor man's RTTI", returns a UClassID for the actual class.
89      *
90      * @internal ICU 3.6
91      */
92     virtual UClassID getDynamicClassID() const;
93 
94     /**
95      * ICU "poor man's RTTI", returns a UClassID for this class.
96      *
97      * @internal ICU 3.6
98      */
99     static UClassID getStaticClassID();
100 
101 protected:
102 
103     /**
104      * This method does Tibetan OpenType character processing. It assigns the OpenType feature
105      * tags to the characters, and may generate output characters which have been reordered.
106      * It may also split some vowels, resulting in more output characters than input characters.
107      *
108      * Input parameters:
109      * @param chars - the input character context
110      * @param offset - the index of the first character to process
111      * @param count - the number of characters to process
112      * @param max - the number of characters in the input context
113      * @param rightToLeft - <code>TRUE</code> if the characters are in a right to left directional run
114      * @param glyphStorage - the glyph storage object. The glyph and character index arrays will be set.
115      *                       the auxillary data array will be set to the feature tags.
116      *
117      * Output parameters:
118      * @param success - set to an error code if the operation fails
119      *
120      * @return the output character count
121      *
122      * @internal
123      */
124     virtual le_int32 characterProcessing(const LEUnicode chars[], le_int32 offset, le_int32 count, le_int32 max, le_bool rightToLeft,
125             LEUnicode *&outChars, LEGlyphStorage &glyphStorage, LEErrorCode &success);
126 
127 };
128 
129 U_NAMESPACE_END
130 #endif
131 
132