/*

 *

 * (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