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/*
* @(#)GXLayoutEngine.h 1.4 00/03/15
*
* (C) Copyright IBM Corp. 1998, 1999, 2000, 2001 - All Rights Reserved
*
*/
#ifndef __GXLAYOUTENGINE_H
#define __GXLAYOUTENGINE_H
#include "LETypes.h"
#include "LEFontInstance.h"
#include "LEGlyphFilter.h"
#include "LayoutEngine.h"
#include "MorphTables.h"
U_NAMESPACE_BEGIN
/**
* This class implements layout for QuickDraw GX or Apple Advanced Typograyph (AAT)
* fonts. A font is a GX or AAT font if it contains a 'mort' table. See Apple's
* TrueType Reference Manual (http://fonts.apple.com/TTRefMan/index.html) for details.
* Information about 'mort' tables is in the chapter titled "Font Files."
*/
class GXLayoutEngine : public LayoutEngine
{
public:
/**
* This is the main constructor. It constructs an instance of GXLayoutEngine for
* a particular font, script and language. It takes the 'mort' table as a parameter since
* LayoutEngine::layoutEngineFactory has to read the 'mort' table to know that it has a
* GX font.
*
* Note: GX and AAT fonts don't contain any script and language specific tables, so
* the script and language are ignored.
*
* @param fontInstance - the font
* @param scriptCode - the script
* @param langaugeCode - the language
* @param morphTable - the 'mort' table
*
* @see LayoutEngine::layoutEngineFactory
* @see ScriptAndLangaugeTags.h for script and language codes
*/
GXLayoutEngine(const LEFontInstance *fontInstance, le_int32 scriptCode, le_int32 languageCode, const MorphTableHeader *morphTable);
/**
* The destructor, virtual for correct polymorphic invocation.
*/
virtual ~GXLayoutEngine();
protected:
/**
* The address of the 'mort' table
*/
const MorphTableHeader *fMorphTable;
/**
* This method does GX layout using the font's 'mort' table. It converts the
* input character codes to glyph indices using mapCharsToGlyphs, and then
* applies the 'mort' table.
*
* 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 text is in a right to left directional run
*
* Output parameters:
* @param glyphs - the glyph index array
* @param charIndices - the character index array
* @param success - set to an error code if the operation fails
*
* @return the number of glyphs in the glyph index array
*/
virtual le_int32 computeGlyphs(const LEUnicode chars[], le_int32 offset, le_int32 count, le_int32 max, le_bool rightToLeft,
LEGlyphID *&glyphs, le_int32 *&charIndices, LEErrorCode &success);
/**
* This method adjusts the glyph positions using the font's
* 'kern', 'trak', 'bsln', 'opbd' and 'just' tables.
*
* Input parameters:
* @param glyphs - the input glyph array
* @param glyphCount - the number of glyphs in the glyph array
* @param x - the starting X position
* @param y - the starting Y position
*
* Output parameters:
* @param positions - the output X and Y positions (two entries per glyph)
* @param success - 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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