/*

  *

  * (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