1 2 /* 3 * 4 * (C) Copyright IBM Corp. 1998-2008 - All Rights Reserved 5 * 6 */ 7 8 #ifndef __ARABICLAYOUTENGINE_H 9 #define __ARABICLAYOUTENGINE_H 10 11 #include "LETypes.h" 12 #include "LEFontInstance.h" 13 #include "LEGlyphFilter.h" 14 #include "LayoutEngine.h" 15 #include "OpenTypeLayoutEngine.h" 16 17 #include "GlyphSubstitutionTables.h" 18 #include "GlyphDefinitionTables.h" 19 #include "GlyphPositioningTables.h" 20 21 U_NAMESPACE_BEGIN 22 23 /** 24 * This class implements OpenType layout for Arabic fonts. It overrides 25 * the characerProcessing method to assign the correct OpenType feature 26 * tags for the Arabic contextual forms. It also overrides the adjustGlyphPositions 27 * method to guarantee that all vowel and accent glyphs have zero advance width. 28 * 29 * @internal 30 */ 31 class ArabicOpenTypeLayoutEngine : public OpenTypeLayoutEngine 32 { 33 public: 34 /** 35 * This is the main constructor. It constructs an instance of ArabicOpenTypeLayoutEngine for 36 * a particular font, script and language. It takes the GSUB table as a parameter since 37 * LayoutEngine::layoutEngineFactory has to read the GSUB table to know that it has an 38 * Indic OpenType font. 39 * 40 * @param fontInstance - the font 41 * @param scriptCode - the script 42 * @param langaugeCode - the language 43 * @param gsubTable - the GSUB table 44 * @param success - set to an error code if the operation fails 45 * 46 * @see LayoutEngine::layoutEngineFactory 47 * @see OpenTypeLayoutEngine 48 * @see ScriptAndLanguageTags.h for script and language codes 49 * 50 * @internal 51 */ 52 ArabicOpenTypeLayoutEngine(const LEFontInstance *fontInstance, le_int32 scriptCode, le_int32 languageCode, 53 le_int32 typoFlags, const GlyphSubstitutionTableHeader *gsubTable, LEErrorCode &success); 54 55 /** 56 * This constructor is used when the font requires a "canned" GSUB table which can't be known 57 * until after this constructor has been invoked. 58 * 59 * @param fontInstance - the font 60 * @param scriptCode - the script 61 * @param langaugeCode - the language 62 * @param success - set to an error code if the operation fails 63 * 64 * @see OpenTypeLayoutEngine 65 * @see ScriptAndLanguageTags.h for script and language codes 66 * 67 * @internal 68 */ 69 ArabicOpenTypeLayoutEngine(const LEFontInstance *fontInstance, le_int32 scriptCode, le_int32 languageCode, 70 le_int32 typoFlags, LEErrorCode &success); 71 72 /** 73 * The destructor, virtual for correct polymorphic invocation. 74 * 75 * @internal 76 */ 77 virtual ~ArabicOpenTypeLayoutEngine(); 78 79 /** 80 * ICU "poor man's RTTI", returns a UClassID for the actual class. 81 * 82 * @stable ICU 2.8 83 */ 84 virtual UClassID getDynamicClassID() const; 85 86 /** 87 * ICU "poor man's RTTI", returns a UClassID for this class. 88 * 89 * @stable ICU 2.8 90 */ 91 static UClassID getStaticClassID(); 92 93 protected: 94 95 /** 96 * This method does Arabic OpenType character processing. It assigns the OpenType feature 97 * tags to the characters to generate the correct contextual forms and ligatures. 98 * 99 * Input parameters: 100 * @param chars - the input character context 101 * @param offset - the index of the first character to process 102 * @param count - the number of characters to process 103 * @param max - the number of characters in the input context 104 * @param rightToLeft - <code>TRUE</code> if the characters are in a right to left directional run 105 * 106 * Output parameters: 107 * @param outChars - the output character arrayt 108 * @param charIndices - the output character index array 109 * @param featureTags - the output feature tag array 110 * @param success - set to an error code if the operation fails 111 * 112 * @return the output character count 113 * 114 * @internal 115 */ 116 virtual le_int32 characterProcessing(const LEUnicode chars[], le_int32 offset, le_int32 count, le_int32 max, le_bool rightToLeft, 117 LEUnicode *&outChars, LEGlyphStorage &glyphStorage, LEErrorCode &success); 118 119 /** 120 * This method applies the GPOS table if it is present, otherwise it ensures that all vowel 121 * and accent glyphs have a zero advance width by calling the adjustMarkGlyphs method. 122 * If the font contains a GDEF table, that is used to identify voewls and accents. Otherwise 123 * the character codes are used. 124 * 125 * @param chars - the input character context 126 * @param offset - the offset of the first character to process 127 * @param count - the number of characters to process 128 * @param reverse - <code>TRUE</code> if the glyphs in the glyph array have been reordered 129 * @param glyphs - the input glyph array 130 * @param glyphCount - the number of glyphs 131 * @param positions - the position array, will be updated as needed 132 * @param success - output parameter set to an error code if the operation fails 133 * 134 * @internal 135 */ 136 virtual void adjustGlyphPositions(const LEUnicode chars[], le_int32 offset, le_int32 count, le_bool reverse, LEGlyphStorage &glyphStorage, LEErrorCode &success); 137 138 // static void adjustMarkGlyphs(const LEUnicode chars[], le_int32 offset, le_int32 count, le_bool rightToLeft, LEGlyphStorage &glyphStorage, LEErrorCode &success); 139 140 }; 141 142 /** 143 * The class implements OpenType layout for Arabic fonts which don't 144 * contain a GSUB table, using a canned GSUB table based on Unicode 145 * Arabic Presentation Forms. It overrides the mapCharsToGlyphs method 146 * to use the Presentation Forms as logical glyph indices. It overrides the 147 * glyphPostProcessing method to convert the Presentation Forms to actual 148 * glyph indices. 149 * 150 * @see ArabicOpenTypeLayoutEngine 151 * 152 * @internal 153 */ 154 class UnicodeArabicOpenTypeLayoutEngine : public ArabicOpenTypeLayoutEngine 155 { 156 public: 157 /** 158 * This constructs an instance of UnicodeArabicOpenTypeLayoutEngine for a specific font, 159 * script and language. 160 * 161 * @param fontInstance - the font 162 * @param scriptCode - the script 163 * @param languageCode - the language 164 * @param success - set to an error code if the operation fails 165 * 166 * @see LEFontInstance 167 * @see ScriptAndLanguageTags.h for script and language codes 168 * 169 * @internal 170 */ 171 UnicodeArabicOpenTypeLayoutEngine(const LEFontInstance *fontInstance, le_int32 scriptCode, le_int32 languageCode, 172 le_int32 typoFlags, LEErrorCode &success); 173 174 /** 175 * The destructor, virtual for correct polymorphic invocation. 176 * 177 * @internal 178 */ 179 virtual ~UnicodeArabicOpenTypeLayoutEngine(); 180 181 protected: 182 183 /** 184 * This method converts the Arabic Presentation Forms in the temp glyph array 185 * into actual glyph indices using ArabicOpenTypeLayoutEngine::mapCharsToGlyps. 186 * 187 * Input paramters: 188 * @param tempGlyphs - the input presentation forms 189 * @param tempCharIndices - the input character index array 190 * @param tempGlyphCount - the number of Presentation Froms 191 * 192 * Output parameters: 193 * @param glyphs - the output glyph index array 194 * @param charIndices - the output character index array 195 * @param success - set to an error code if the operation fails 196 * 197 * @return the number of glyph indices in the output glyph index array 198 * 199 * @internal 200 */ 201 virtual le_int32 glyphPostProcessing(LEGlyphStorage &tempGlyphStorage, LEGlyphStorage &glyphStorage, LEErrorCode &success); 202 203 /** 204 * This method copies the input characters into the output glyph index array, 205 * for use by the canned GSUB table. It also generates the character index array. 206 * 207 * Input parameters: 208 * @param chars - the input character context 209 * @param offset - the offset of the first character to be mapped 210 * @param count - the number of characters to be mapped 211 * @param reverse - if <code>TRUE</code>, the output will be in reverse order 212 * @param mirror - if <code>TRUE</code>, do character mirroring 213 * @param glyphStorage - the glyph storage object. Glyph and char index arrays will be updated. 214 * 215 * @param success - set to an error code if the operation fails 216 * 217 * @internal 218 */ 219 virtual void mapCharsToGlyphs(const LEUnicode chars[], le_int32 offset, le_int32 count, le_bool reverse, le_bool mirror, 220 LEGlyphStorage &glyphStorage, LEErrorCode &success); 221 222 /** 223 * This method ensures that all vowel and accent glyphs have a zero advance width by calling 224 * the adjustMarkGlyphs method. The character codes are used to identify the vowel and mark 225 * glyphs. 226 * 227 * @param chars - the input character context 228 * @param offset - the offset of the first character to process 229 * @param count - the number of characters to process 230 * @param reverse - <code>TRUE</code> if the glyphs in the glyph array have been reordered 231 * @param glyphStorage - the glyph storage object. The glyph positions will be updated as needed. 232 * @param success - output parameter set to an error code if the operation fails 233 * 234 * @internal 235 */ 236 virtual void adjustGlyphPositions(const LEUnicode chars[], le_int32 offset, le_int32 count, le_bool reverse, LEGlyphStorage &glyphStorage, LEErrorCode &success); 237 }; 238 239 U_NAMESPACE_END 240 #endif 241 242
