/*

  *

  * (C) Copyright IBM Corp. 1998-2004 - All Rights Reserved

  *

  */

 #ifndef __GXLAYOUTENGINE_H

 #define __GXLAYOUTENGINE_H

 #include "LETypes.h"

 #include "LayoutEngine.h"

 #include "MorphTables.h"

 U_NAMESPACE_BEGIN

 class LEFontInstance;

 class LEGlyphStorage;

 /**

  * 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."

  *

  * @internal

  */

 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

      *

      * @internal

      */

     GXLayoutEngine(const LEFontInstance *fontInstance, le_int32 scriptCode, le_int32 languageCode, const MorphTableHeader *morphTable);

     /**

      * The destructor, virtual for correct polymorphic invocation.

      *

      * @internal

      */

     virtual ~GXLayoutEngine();

     /**

      * ICU "poor man's RTTI", returns a UClassID for the actual class.

      *

      * @stable ICU 2.8

      */

     virtual UClassID getDynamicClassID() const;

     /**

      * ICU "poor man's RTTI", returns a UClassID for this class.

      *

      * @stable ICU 2.8

      */

     static UClassID getStaticClassID();

 protected:

     /**

      * The address of the 'mort' table

      *

      * @internal

      */

     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 - <code>TRUE</code> if the text is in a right to left directional run

      * @param glyphStorage - the glyph storage object. The glyph and char index arrays will be set.

      *

      * Output parameters:

      * @param success - set to an error code if the operation fails

      *

      * @return the number of glyphs in the glyph index array

      *

      * @internal

      */

     virtual le_int32 computeGlyphs(const LEUnicode chars[], le_int32 offset, le_int32 count, le_int32 max, le_bool rightToLeft,

         LEGlyphStorage &glyphStorage, LEErrorCode &success);

     /**

      * This method adjusts the glyph positions using the font's

      * 'kern', 'trak', 'bsln', 'opbd' and 'just' tables.

      *

      * Input parameters:

      * @param glyphStorage - the object holding the glyph storage. The positions will be updated as needed.

      *

      * Output parameters:

      * @param success - set to an error code if the operation fails

      *

      * @internal

      */

     virtual void adjustGlyphPositions(const LEUnicode chars[], le_int32 offset, le_int32 count, le_bool reverse,

                                       LEGlyphStorage &glyphStorage, LEErrorCode &success);

 };

 U_NAMESPACE_END

 #endif