diff -r 000000000000 -r 1fb32624e06b fontservices/textshaperplugin/IcuSource/layout/IndicLayoutEngine.h --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/fontservices/textshaperplugin/IcuSource/layout/IndicLayoutEngine.h Tue Feb 02 02:02:46 2010 +0200 @@ -0,0 +1,162 @@ + +/* + * + * (C) Copyright IBM Corp. 1998-2005 - 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 + * + * @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, 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 + * + * @internal + */ + IndicOpenTypeLayoutEngine(const LEFontInstance *fontInstance, le_int32 scriptCode, le_int32 languageCode, + le_int32 typoFlags); + + /** + * 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 - TRUE 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 - TRUE 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); + +private: + + MPreFixups *fMPreFixups; +}; + +U_NAMESPACE_END +#endif +