| |
| /* |
| * @(#)IndicLayoutEngine.h 1.4 00/03/15 |
| * |
| * (C) Copyright IBM Corp. 1998, 1999, 2000 - 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" |
| |
| #include "CDACLayout.h" |
| #include <string.h> |
| |
| /** |
| * 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) |
| */ |
| 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 |
| */ |
| IndicOpenTypeLayoutEngine(LEFontInstance *fontInstance, le_int32 scriptCode, le_int32 languageCode, |
| 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 |
| */ |
| IndicOpenTypeLayoutEngine(LEFontInstance *fontInstance, le_int32 scriptCode, le_int32 languageCode); |
| |
| /** |
| * The destructor, virtual for correct polymorphic invocation. |
| */ |
| virtual ~IndicOpenTypeLayoutEngine(); |
| |
| 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 |
| * |
| * Output parameters: |
| * @param outChars - the output character arrayt |
| * @param charIndices - the output character index array |
| * @param featureTags - the output feature tag array |
| * |
| * @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); |
| |
| /** |
| * 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 |
| * |
| * Output parameters: |
| * @param glyphs - the output glyph index array |
| * @param charIndices - the output character index array |
| * |
| * @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. |
| */ |
| // Input: characters, tags |
| // Output: glyphs, char indices |
| virtual le_int32 glyphProcessing(const LEUnicode chars[], le_int32 offset, le_int32 count, le_int32 max, le_bool rightToLeft, |
| const LETag **featureTags, LEGlyphID *&glyphs, le_int32 *&charIndices); |
| }; |
| |
| /** |
| * This class implements Indic OpenType layout for CDAC fonts. Since CDAC fonts don't contain |
| * a GSUB table, it uses a canned GSUB table, using logical glyph indices. Each logical glyph |
| * may be rendered with several physical glyphs in the CDAC font. It uses the CDACLayout class |
| * to do the layout. |
| * |
| * @see CDACLayout |
| * @see IndicOpenTypeLayout |
| */ |
| class CDACOpenTypeLayoutEngine : public IndicOpenTypeLayoutEngine |
| { |
| public: |
| /** |
| * This constructs an instance of CDACOpenTypeLayoutEngine for a specific font, script and |
| * language. The scriptInfo parameter contains the information that CDACLayout needs to |
| * layout using the font, including the character to logical glyph mapping information, |
| * the canned GSUB table, and the map from logical to physical glyphs. This will be obtained |
| * by LayoutEngine::layoutEngineFactory to determine if the font is a CDAC font. |
| * |
| * @param fontInstance - the font |
| * @param scriptCode - the script |
| * @param languageCode - the language |
| * @param scriptInfo - the CDAC script information |
| * |
| * @see LEFontInstance |
| * @see CDACLayout |
| * @see ScriptAndLanguageTags.h for script and language codes |
| */ |
| CDACOpenTypeLayoutEngine(LEFontInstance *fontInstance, le_int32 scriptCode, le_int32 languageCode, |
| const CDACLayout::ScriptInfo *scriptInfo); |
| |
| /** |
| * The destructor, virtual for correct polymorphic invocation. |
| */ |
| virtual ~CDACOpenTypeLayoutEngine(); |
| |
| protected: |
| const CDACLayout::ScriptInfo *fScriptInfo; |
| |
| /** |
| * This method converts logical glyph indices to physical glyph indices. |
| * |
| * Input paramters: |
| * @param tempGlyphs - the input "fake" glyph index array |
| * @param tempCharIndices - the input "fake" character index array |
| * @param tempGlyphCount - the number of "fake" glyph indices |
| * |
| * Output parameters: |
| * @param glyphs - the output glyph index array |
| * @param charIndices - the output character index array |
| * |
| * @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); |
| |
| /** |
| * This method maps charcters to logical glyph indices. |
| * |
| * 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 should be in reverse order |
| * @param mirror - if true, map characters like parenthesis to their mirror image |
| * |
| * Output parameters: |
| * @param glyphs - the glyph array |
| * @param charIndices - the character index array |
| */ |
| virtual void mapCharsToGlyphs(const LEUnicode chars[], le_int32 offset, le_int32 count, le_bool reverse, le_bool mirror, |
| LEGlyphID *&glyphs, le_int32 *&charIndices); |
| }; |
| |
| #endif |
| |