/*

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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/*

 *

 * (C) Copyright IBM Corp. 1998-2010 - All Rights Reserved

 *

 */

#ifndef __THAILAYOUTENGINE_H

#define __THAILAYOUTENGINE_H

#include "LETypes.h"

#include "LEFontInstance.h"

#include "LayoutEngine.h"

#include "ThaiShaping.h"

U_NAMESPACE_BEGIN

class LEGlyphStorage;

/**

 * This class implements layout for the Thai script, using the ThaiShapingClass.

 * All existing Thai fonts use an encoding which assigns character codes to all

 * the variant forms needed to display accents and tone marks correctly in context.

 * This class can deal with fonts using the Microsoft, Macintosh, and WorldType encodings.

 *

 * @internal

 */

class ThaiLayoutEngine : public LayoutEngine

{

public:

    /**

     * This constructs an instance of ThaiLayoutEngine for the given font, script and

     * language. It examines the font, using LEFontInstance::canDisplay, to set fGlyphSet

     * and fErrorChar. (see below)

     *

     * @param fontInstance - the font

     * @param scriptCode - the script

     * @param languageCode - the language

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

     *

     * @see LEFontInstance

     * @see ScriptAndLanguageTags.h for script and language codes

     *

     * @internal

     */

    ThaiLayoutEngine(const LEFontInstance *fontInstance, le_int32 scriptCode, le_int32 languageCode, le_int32 typoFlags, LEErrorCode &success);

    /**

     * The destructor, virtual for correct polymorphic invocation.

     *

     * @internal

     */

    virtual ~ThaiLayoutEngine();

    /**

     * 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:

    /**

     * A small integer indicating which Thai encoding

     * the font uses.

     *

     * @see ThaiShaping

     *

     * @internal

     */

    le_uint8 fGlyphSet;

    /**

     * The character used as a base for vowels and

     * tone marks that are out of sequence. Usually

     * this will be Unicode 0x25CC, if the font can

     * display it.

     *

     * @see ThaiShaping

     *

     * @internal

     */

    LEUnicode fErrorChar;

    /**

     * This method performs Thai layout. It calls ThaiShaping::compose to

     * generate the correct contextual character codes, and then calls

     * mapCharsToGlyphs to generate the glyph indices.

     *

     * 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

     *

     * @see ThaiShaping

     *

     * @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 does positioning adjustments like accent positioning and

     * kerning. The default implementation does nothing. Subclasses needing

     * position adjustments must override this method.

     *

     * Note that this method has both characters and glyphs as input so that

     * it can use the character codes to determine glyph types if that information

     * isn't directly available. (e.g. Some Arabic OpenType fonts don't have a GDEF

     * table)

     *

     * @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 - <code>TRUE</code> if the glyphs in the glyph array have been reordered

     * @param glyphStorage - the object which holds the per-glyph storage. The glyph positions will be

     *                       adjusted as needed.

     * @param success - output parameter 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