/*

 *

 * (C) Copyright IBM Corp. 1998-2005 - All Rights Reserved

 *

 */

#ifndef __ARABICLAYOUTENGINE_H

#define __ARABICLAYOUTENGINE_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"

U_NAMESPACE_BEGIN

/**

 * This class implements OpenType layout for Arabic fonts. It overrides

 * the characerProcessing method to assign the correct OpenType feature

 * tags for the Arabic contextual forms. It also overrides the adjustGlyphPositions

 * method to guarantee that all vowel and accent glyphs have zero advance width.

 *

 * @internal

 */

class ArabicOpenTypeLayoutEngine : public OpenTypeLayoutEngine

{

public:

    /**

     * This is the main constructor. It constructs an instance of ArabicOpenTypeLayoutEngine 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 ScriptAndLanguageTags.h for script and language codes

     *

     * @internal

     */

    ArabicOpenTypeLayoutEngine(const LEFontInstance *fontInstance, le_int32 scriptCode, le_int32 languageCode,

                            le_int32 typoFlags, 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 ScriptAndLanguageTags.h for script and language codes

     *

     * @internal

     */

    ArabicOpenTypeLayoutEngine(const LEFontInstance *fontInstance, le_int32 scriptCode, le_int32 languageCode,

			       le_int32 typoFlags);

    /**

     * The destructor, virtual for correct polymorphic invocation.

     *

     * @internal

     */

    virtual ~ArabicOpenTypeLayoutEngine();

    /**

     * 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:

    /**

     * This method does Arabic OpenType character processing. It assigns the OpenType feature

     * tags to the characters to generate the correct contextual forms and ligatures.

     *

     * 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 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

     *

     * @internal

     */

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

            LEUnicode *&outChars, LEGlyphStorage &glyphStorage, LEErrorCode &success);

    /**

     * This method applies the GPOS table if it is present, otherwise it ensures that all vowel

     * and accent glyphs have a zero advance width by calling the adjustMarkGlyphs method.

     * If the font contains a GDEF table, that is used to identify voewls and accents. Otherwise

     * the character codes are used.

     *

     * @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 glyphs - the input glyph array

     * @param glyphCount - the number of glyphs

     * @param positions - the position array, will be updated 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);

    // static void adjustMarkGlyphs(const LEUnicode chars[], le_int32 offset, le_int32 count, le_bool rightToLeft, LEGlyphStorage &glyphStorage, LEErrorCode &success);

};

/**

 * The class implements OpenType layout for Arabic fonts which don't

 * contain a GSUB table, using a canned GSUB table based on Unicode

 * Arabic Presentation Forms. It overrides the mapCharsToGlyphs method

 * to use the Presentation Forms as logical glyph indices. It overrides the

 * glyphPostProcessing method to convert the Presentation Forms to actual

 * glyph indices.

 *

 * @see ArabicOpenTypeLayoutEngine

 *

 * @internal

 */

class UnicodeArabicOpenTypeLayoutEngine : public ArabicOpenTypeLayoutEngine

{

public:

    /**

     * This constructs an instance of UnicodeArabicOpenTypeLayoutEngine for a specific font,

     * script and language.

     *

     * @param fontInstance - the font

     * @param scriptCode - the script

     * @param languageCode - the language

     *

     * @see LEFontInstance

     * @see ScriptAndLanguageTags.h for script and language codes

     *

     * @internal

     */

    UnicodeArabicOpenTypeLayoutEngine(const LEFontInstance *fontInstance, le_int32 scriptCode, le_int32 languageCode,

		le_int32 typoFlags);

    /**

     * The destructor, virtual for correct polymorphic invocation.

     *

     * @internal

     */

    virtual ~UnicodeArabicOpenTypeLayoutEngine();

protected:

    /**

     * This method converts the Arabic Presentation Forms in the temp glyph array

     * into actual glyph indices using ArabicOpenTypeLayoutEngine::mapCharsToGlyps.

     *

     * Input paramters:

     * @param tempGlyphs - the input presentation forms

     * @param tempCharIndices - the input character index array

     * @param tempGlyphCount - the number of Presentation Froms

     *

     * 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 glyph indices in the output glyph index array

     *

     * @internal

     */

    virtual le_int32 glyphPostProcessing(LEGlyphStorage &tempGlyphStorage, LEGlyphStorage &glyphStorage, LEErrorCode &success);

    /**

     * This method copies the input characters into the output glyph index array,

     * for use by the canned GSUB table. It also generates the character index array.

     *

     * Input parameters:

     * @param chars - the input character context

     * @param offset - the offset of the first character to be mapped

     * @param count - the number of characters to be mapped

     * @param reverse - if <code>TRUE</code>, the output will be in reverse order

     * @param mirror - if <code>TRUE</code>, do character mirroring

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

     *

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

     *

     * @internal

     */

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

        LEGlyphStorage &glyphStorage, LEErrorCode &success);

    /**

     * This method ensures that all vowel and accent glyphs have a zero advance width by calling

     * the adjustMarkGlyphs method. The character codes are used to identify the vowel and mark

     * glyphs.

     *

     * @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 glyph storage object. The glyph positions will be updated 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