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/*
* @(#)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();
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);
};
/**
* 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
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