sl@0:
sl@0: /*
sl@0: *
sl@0: * (C) Copyright IBM Corp. 1998-2005 - All Rights Reserved
sl@0: *
sl@0: */
sl@0:
sl@0: #ifndef __INDICLAYOUTENGINE_H
sl@0: #define __INDICLAYOUTENGINE_H
sl@0:
sl@0: #include "LETypes.h"
sl@0: #include "LEFontInstance.h"
sl@0: #include "LEGlyphFilter.h"
sl@0: #include "LayoutEngine.h"
sl@0: #include "OpenTypeLayoutEngine.h"
sl@0:
sl@0: #include "GlyphSubstitutionTables.h"
sl@0: #include "GlyphDefinitionTables.h"
sl@0: #include "GlyphPositioningTables.h"
sl@0:
sl@0: U_NAMESPACE_BEGIN
sl@0:
sl@0: class MPreFixups;
sl@0: class LEGlyphStorage;
sl@0:
sl@0: /**
sl@0: * This class implements OpenType layout for Indic OpenType fonts, as
sl@0: * specified by Microsoft in "Creating and Supporting OpenType Fonts for
sl@0: * Indic Scripts" (http://www.microsoft.com/typography/otspec/indicot/default.htm)
sl@0: *
sl@0: * This class overrides the characterProcessing method to do Indic character processing
sl@0: * and reordering, and the glyphProcessing method to implement post-GSUB processing for
sl@0: * left matras. (See the MS spec. for more details)
sl@0: *
sl@0: * @internal
sl@0: */
sl@0: class IndicOpenTypeLayoutEngine : public OpenTypeLayoutEngine
sl@0: {
sl@0: public:
sl@0: /**
sl@0: * This is the main constructor. It constructs an instance of IndicOpenTypeLayoutEngine for
sl@0: * a particular font, script and language. It takes the GSUB table as a parameter since
sl@0: * LayoutEngine::layoutEngineFactory has to read the GSUB table to know that it has an
sl@0: * Indic OpenType font.
sl@0: *
sl@0: * @param fontInstance - the font
sl@0: * @param scriptCode - the script
sl@0: * @param langaugeCode - the language
sl@0: * @param gsubTable - the GSUB table
sl@0: *
sl@0: * @see LayoutEngine::layoutEngineFactory
sl@0: * @see OpenTypeLayoutEngine
sl@0: * @see ScriptAndLangaugeTags.h for script and language codes
sl@0: *
sl@0: * @internal
sl@0: */
sl@0: IndicOpenTypeLayoutEngine(const LEFontInstance *fontInstance, le_int32 scriptCode, le_int32 languageCode,
sl@0: le_int32 typoFlags, const GlyphSubstitutionTableHeader *gsubTable);
sl@0:
sl@0: /**
sl@0: * This constructor is used when the font requires a "canned" GSUB table which can't be known
sl@0: * until after this constructor has been invoked.
sl@0: *
sl@0: * @param fontInstance - the font
sl@0: * @param scriptCode - the script
sl@0: * @param langaugeCode - the language
sl@0: *
sl@0: * @see OpenTypeLayoutEngine
sl@0: * @see ScriptAndLangaugeTags.h for script and language codes
sl@0: *
sl@0: * @internal
sl@0: */
sl@0: IndicOpenTypeLayoutEngine(const LEFontInstance *fontInstance, le_int32 scriptCode, le_int32 languageCode,
sl@0: le_int32 typoFlags);
sl@0:
sl@0: /**
sl@0: * The destructor, virtual for correct polymorphic invocation.
sl@0: *
sl@0: * @internal
sl@0: */
sl@0: virtual ~IndicOpenTypeLayoutEngine();
sl@0:
sl@0: /**
sl@0: * ICU "poor man's RTTI", returns a UClassID for the actual class.
sl@0: *
sl@0: * @stable ICU 2.8
sl@0: */
sl@0: virtual UClassID getDynamicClassID() const;
sl@0:
sl@0: /**
sl@0: * ICU "poor man's RTTI", returns a UClassID for this class.
sl@0: *
sl@0: * @stable ICU 2.8
sl@0: */
sl@0: static UClassID getStaticClassID();
sl@0:
sl@0: protected:
sl@0:
sl@0: /**
sl@0: * This method does Indic OpenType character processing. It assigns the OpenType feature
sl@0: * tags to the characters, and may generate output characters which have been reordered. For
sl@0: * some Indic scripts, it may also split some vowels, resulting in more output characters
sl@0: * than input characters.
sl@0: *
sl@0: * Input parameters:
sl@0: * @param chars - the input character context
sl@0: * @param offset - the index of the first character to process
sl@0: * @param count - the number of characters to process
sl@0: * @param max - the number of characters in the input context
sl@0: * @param rightToLeft - <code>TRUE</code> if the characters are in a right to left directional run
sl@0: * @param glyphStorage - the glyph storage object. The glyph and character index arrays will be set.
sl@0: * the auxillary data array will be set to the feature tags.
sl@0: *
sl@0: * Output parameters:
sl@0: * @param success - set to an error code if the operation fails
sl@0: *
sl@0: * @return the output character count
sl@0: *
sl@0: * @internal
sl@0: */
sl@0: virtual le_int32 characterProcessing(const LEUnicode chars[], le_int32 offset, le_int32 count, le_int32 max, le_bool rightToLeft,
sl@0: LEUnicode *&outChars, LEGlyphStorage &glyphStorage, LEErrorCode &success);
sl@0:
sl@0: /**
sl@0: * This method does character to glyph mapping, applies the GSUB table and applies
sl@0: * any post GSUB fixups for left matras. It calls OpenTypeLayoutEngine::glyphProcessing
sl@0: * to do the character to glyph mapping, and apply the GSUB table.
sl@0: *
sl@0: * Note that in the case of "canned" GSUB tables, the output glyph indices may be
sl@0: * "fake" glyph indices that need to be converted to "real" glyph indices by the
sl@0: * glyphPostProcessing method.
sl@0: *
sl@0: * Input parameters:
sl@0: * @param chars - the input character context
sl@0: * @param offset - the index of the first character to process
sl@0: * @param count - the number of characters to process
sl@0: * @param max - the number of characters in the input context
sl@0: * @param rightToLeft - <code>TRUE</code> if the characters are in a right to left directional run
sl@0: * @param featureTags - the feature tag array
sl@0: * @param glyphStorage - the glyph storage object. The glyph and char index arrays will be set.
sl@0: *
sl@0: * Output parameters:
sl@0: * @param success - set to an error code if the operation fails
sl@0: *
sl@0: * @return the number of glyphs in the output glyph index array
sl@0: *
sl@0: * Note: if the character index array was already set by the characterProcessing
sl@0: * method, this method won't change it.
sl@0: *
sl@0: * @internal
sl@0: */
sl@0: virtual le_int32 glyphProcessing(const LEUnicode chars[], le_int32 offset, le_int32 count, le_int32 max, le_bool rightToLeft,
sl@0: LEGlyphStorage &glyphStorage, LEErrorCode &success);
sl@0:
sl@0: private:
sl@0:
sl@0: MPreFixups *fMPreFixups;
sl@0: };
sl@0:
sl@0: U_NAMESPACE_END
sl@0: #endif
sl@0: