1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
|
/*
*
* (C) Copyright IBM Corp. 1998-2009 - All Rights Reserved
*
*/
#ifndef __INDICLAYOUTENGINE_H
#define __INDICLAYOUTENGINE_H
#include "LETypes.h"
#include "LEFontInstance.h"
#include "LEGlyphFilter.h"
#include "LayoutEngine.h"
#include "OpenTypeLayoutEngine.h"
#include "GlyphSubstitutionTables.h"
#include "GlyphDefinitionTables.h"
#include "GlyphPositioningTables.h"
U_NAMESPACE_BEGIN
class MPreFixups;
class LEGlyphStorage;
/**
* This class implements OpenType layout for Indic OpenType fonts, as
* specified by Microsoft in "Creating and Supporting OpenType Fonts for
* Indic Scripts" (http://www.microsoft.com/typography/otspec/indicot/default.htm)
*
* This class overrides the characterProcessing method to do Indic character processing
* and reordering, and the glyphProcessing method to implement post-GSUB processing for
* left matras. (See the MS spec. for more details)
*
* @internal
*/
class IndicOpenTypeLayoutEngine : public OpenTypeLayoutEngine
{
public:
/**
* This is the main constructor. It constructs an instance of IndicOpenTypeLayoutEngine for
* a particular font, script and language. It takes the GSUB table as a parameter since
* LayoutEngine::layoutEngineFactory has to read the GSUB table to know that it has an
* Indic OpenType font.
*
* @param fontInstance - the font
* @param scriptCode - the script
* @param langaugeCode - the language
* @param gsubTable - the GSUB table
* @param success - set to an error code if the operation fails
*
* @see LayoutEngine::layoutEngineFactory
* @see OpenTypeLayoutEngine
* @see ScriptAndLangaugeTags.h for script and language codes
*
* @internal
*/
IndicOpenTypeLayoutEngine(const LEFontInstance *fontInstance, le_int32 scriptCode, le_int32 languageCode,
le_int32 typoFlags, le_bool version2, const GlyphSubstitutionTableHeader *gsubTable, LEErrorCode &success);
/**
* This constructor is used when the font requires a "canned" GSUB table which can't be known
* until after this constructor has been invoked.
*
* @param fontInstance - the font
* @param scriptCode - the script
* @param langaugeCode - the language
* @param success - set to an error code if the operation fails
*
* @see OpenTypeLayoutEngine
* @see ScriptAndLangaugeTags.h for script and language codes
*
* @internal
*/
IndicOpenTypeLayoutEngine(const LEFontInstance *fontInstance, le_int32 scriptCode, le_int32 languageCode,
le_int32 typoFlags, LEErrorCode &success);
/**
* The destructor, virtual for correct polymorphic invocation.
*
* @internal
*/
virtual ~IndicOpenTypeLayoutEngine();
/**
* ICU "poor man's RTTI", returns a UClassID for the actual class.
*
* @stable ICU 2.8
*/
virtual UClassID getDynamicClassID() const;
/**
* ICU "poor man's RTTI", returns a UClassID for this class.
*
* @stable ICU 2.8
*/
static UClassID getStaticClassID();
protected:
/**
* This method does Indic OpenType character processing. It assigns the OpenType feature
* tags to the characters, and may generate output characters which have been reordered. For
* some Indic scripts, it may also split some vowels, resulting in more output characters
* than input characters.
*
* Input parameters:
* @param chars - the input character context
* @param offset - the index of the first character to process
* @param count - the number of characters to process
* @param max - the number of characters in the input context
* @param rightToLeft - <code>TRUE</code> if the characters are in a right to left directional run
* @param glyphStorage - the glyph storage object. The glyph and character index arrays will be set.
* the auxillary data array will be set to the feature tags.
*
* Output parameters:
* @param success - set to an error code if the operation fails
*
* @return the output character count
*
* @internal
*/
virtual le_int32 characterProcessing(const LEUnicode chars[], le_int32 offset, le_int32 count, le_int32 max, le_bool rightToLeft,
LEUnicode *&outChars, LEGlyphStorage &glyphStorage, LEErrorCode &success);
/**
* This method does character to glyph mapping, applies the GSUB table and applies
* any post GSUB fixups for left matras. It calls OpenTypeLayoutEngine::glyphProcessing
* to do the character to glyph mapping, and apply the GSUB table.
*
* Note that in the case of "canned" GSUB tables, the output glyph indices may be
* "fake" glyph indices that need to be converted to "real" glyph indices by the
* glyphPostProcessing method.
*
* Input parameters:
* @param chars - the input character context
* @param offset - the index of the first character to process
* @param count - the number of characters to process
* @param max - the number of characters in the input context
* @param rightToLeft - <code>TRUE</code> if the characters are in a right to left directional run
* @param featureTags - the feature tag array
* @param glyphStorage - the glyph storage object. The glyph and char index arrays will be set.
*
* Output parameters:
* @param success - set to an error code if the operation fails
*
* @return the number of glyphs in the output glyph index array
*
* Note: if the character index array was already set by the characterProcessing
* method, this method won't change it.
*
* @internal
*/
virtual le_int32 glyphProcessing(const LEUnicode chars[], le_int32 offset, le_int32 count, le_int32 max, le_bool rightToLeft,
LEGlyphStorage &glyphStorage, LEErrorCode &success);
le_bool fVersion2;
private:
MPreFixups *fMPreFixups;
};
U_NAMESPACE_END
#endif
|
