/* * @(#)ArabicLayoutEngine.h 1.3 00/03/15 * * (C) Copyright IBM Corp. 1998, 1999, 2000, 2001 - All Rights Reserved * */ #ifndef __ARABICLAYOUTENGINE_H #define __ARABICLAYOUTENGINE_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 /** * This class implements OpenType layout for Arabic fonts. It overrides * the characerProcessing method to assign the correct OpenType feature * tags for the Arabic contextual forms. It also overrides the adjustGlyphPositions * method to guarantee that all vowel and accent glyphs have zero advance width. */ class ArabicOpenTypeLayoutEngine : public OpenTypeLayoutEngine { public: /** * This is the main constructor. It constructs an instance of ArabicOpenTypeLayoutEngine 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 * * @see LayoutEngine::layoutEngineFactory * @see OpenTypeLayoutEngine * @see ScriptAndLangaugeTags.h for script and language codes */ ArabicOpenTypeLayoutEngine(const LEFontInstance *fontInstance, le_int32 scriptCode, le_int32 languageCode, const GlyphSubstitutionTableHeader *gsubTable); /** * 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 * * @see OpenTypeLayoutEngine * @see ScriptAndLangaugeTags.h for script and language codes */ ArabicOpenTypeLayoutEngine(const LEFontInstance *fontInstance, le_int32 scriptCode, le_int32 languageCode); /** * The destructor, virtual for correct polymorphic invocation. */ virtual ~ArabicOpenTypeLayoutEngine(); /** * ICU "poor man's RTTI", returns a UClassID for the actual class. * * @draft ICU 2.2 */ virtual inline UClassID getDynamicClassID() const { return getStaticClassID(); } /** * ICU "poor man's RTTI", returns a UClassID for this class. * * @draft ICU 2.2 */ static inline UClassID getStaticClassID() { return (UClassID)&fgClassID; } protected: /** * This method does Arabic OpenType character processing. It assigns the OpenType feature * tags to the characters to generate the correct contextual forms and ligatures. * * 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 - true if the characters are in a right to left directional run * * Output parameters: * @param outChars - the output character arrayt * @param charIndices - the output character index array * @param featureTags - the output feature tag array * @param success - set to an error code if the operation fails * * @return the output character count */ virtual le_int32 characterProcessing(const LEUnicode chars[], le_int32 offset, le_int32 count, le_int32 max, le_bool rightToLeft, LEUnicode *&outChars, le_int32 *&charIndices, const LETag **&featureTags, LEErrorCode &success); /** * This method applies the GPOS table if it is present, otherwise it ensures that all vowel * and accent glyphs have a zero advance width by calling the adjustMarkGlyphs method. * If the font contains a GDEF table, that is used to identify voewls and accents. Otherwise * the character codes are used. * * @param chars - the input character context * @param offset - the offset of the first character to process * @param count - the number of characters to process * @param reverse - true if the glyphs in the glyph array have been reordered * @param glyphs - the input glyph array * @param glyphCount - the number of glyphs * @param positions - the position array, will be updated as needed * @param success - output parameter set to an error code if the operation fails */ virtual void adjustGlyphPositions(const LEUnicode chars[], le_int32 offset, le_int32 count, le_bool reverse, LEGlyphID glyphs[], le_int32 glyphCount, float positions[], LEErrorCode &success); private: /** * The address of this static class variable serves as this class's ID * for ICU "poor man's RTTI". */ static const char fgClassID; }; /** * The class implements OpenType layout for Arabic fonts which don't * contain a GSUB table, using a canned GSUB table based on Unicode * Arabic Presentation Forms. It overrides the mapCharsToGlyphs method * to use the Presentation Forms as logical glyph indices. It overrides the * glyphPostProcessing method to convert the Presentation Forms to actual * glyph indices. * * @see ArabicOpenTypeLayoutEngine */ class UnicodeArabicOpenTypeLayoutEngine : public ArabicOpenTypeLayoutEngine { public: /** * This constructs an instance of UnicodeArabicOpenTypeLayoutEngine for a specific font, * script and language. * * @param fontInstance - the font * @param scriptCode - the script * @param languageCode - the language * * @see LEFontInstance * @see ScriptAndLanguageTags.h for script and language codes */ UnicodeArabicOpenTypeLayoutEngine(const LEFontInstance *fontInstance, le_int32 scriptCode, le_int32 languageCode); /** * The destructor, virtual for correct polymorphic invocation. */ virtual ~UnicodeArabicOpenTypeLayoutEngine(); protected: /** * This method converts the Arabic Presentation Forms in the temp glyph array * into actual glyph indices using ArabicOpenTypeLayoutEngine::mapCharsToGlyps. * * Input paramters: * @param tempGlyphs - the input presentation forms * @param tempCharIndices - the input character index array * @param tempGlyphCount - the number of Presentation Froms * * Output parameters: * @param glyphs - the output glyph index array * @param charIndices - the output character index array * @param success - set to an error code if the operation fails * * @return the number of glyph indices in the output glyph index array */ virtual le_int32 glyphPostProcessing(LEGlyphID tempGlyphs[], le_int32 tempCharIndices[], le_int32 tempGlyphCount, LEGlyphID *&glyphs, le_int32 *&charIndices, LEErrorCode &success); /** * This method copies the input characters into the output glyph index array, * for use by the canned GSUB table. It also generates the character index array. * * Input parameters: * @param chars - the input character context * @param offset - the offset of the first character to be mapped * @param count - the number of characters to be mapped * @param reverse - if true, the output will be in reverse order * @param mirror - if true, do character mirroring * * Output parameters: * @param glyphs - the glyph array * @param charIndices - the character index array * @param success - set to an error code if the operation fails */ virtual void mapCharsToGlyphs(const LEUnicode chars[], le_int32 offset, le_int32 count, le_bool reverse, le_bool mirror, LEGlyphID *&glyphs, le_int32 *&charIndices, LEErrorCode &success); /** * This method ensures that all vowel and accent glyphs have a zero advance width by calling * the adjustMarkGlyphs method. The character codes are used to identify the vowel and mark * glyphs. * * @param chars - the input character context * @param offset - the offset of the first character to process * @param count - the number of characters to process * @param reverse - true if the glyphs in the glyph array have been reordered * @param glyphs - the input glyph array * @param glyphCount - the number of glyphs * @param positions - the position array, will be updated as needed * @param success - output parameter set to an error code if the operation fails */ virtual void adjustGlyphPositions(const LEUnicode chars[], le_int32 offset, le_int32 count, le_bool reverse, LEGlyphID glyphs[], le_int32 glyphCount, float positions[], LEErrorCode &success); }; U_NAMESPACE_END #endif