136 lines
5.3 KiB
C++
136 lines
5.3 KiB
C++
|
|
/*
|
|
* @(#)IndicLayoutEngine.h 1.4 00/03/15
|
|
*
|
|
* (C) Copyright IBM Corp. 1998, 1999, 2000, 2001 - 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 <string.h>
|
|
|
|
U_NAMESPACE_BEGIN
|
|
|
|
/**
|
|
* 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(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
|
|
*/
|
|
IndicOpenTypeLayoutEngine(const 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
|
|
* @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 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
|
|
* @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.
|
|
*/
|
|
// 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, LEErrorCode &success);
|
|
};
|
|
|
|
U_NAMESPACE_END
|
|
#endif
|
|
|