1 

     2 /*

     3  *

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

     5  *

     6  * This file is a modification of the ICU file IndicLayoutEngine.h

     7  * by Jens Herden and Javier Sola for Khmer language 

     8  *

     9  */

    10 

    11 #ifndef __KHMERLAYOUTENGINE_H

    12 #define __KHMERLAYOUTENGINE_H

    13 

    14 // #include "LETypes.h"

    15 // #include "LEFontInstance.h"

    16 // #include "LEGlyphFilter.h"

    17 // #include "LayoutEngine.h"

    18 // #include "OpenTypeLayoutEngine.h"

    19 

    20 // #include "GlyphSubstitutionTables.h"

    21 // #include "GlyphDefinitionTables.h"

    22 // #include "GlyphPositioningTables.h"

    23 

    24 U_NAMESPACE_BEGIN

    25 

    26 // class MPreFixups;

    27 // class LEGlyphStorage;

    28 

    29 /**

    30  * This class implements OpenType layout for Khmer OpenType fonts, as

    31  * specified by Microsoft in "Creating and Supporting OpenType Fonts for

    32  * Khmer Scripts" (http://www.microsoft.com/typography/otspec/indicot/default.htm) TODO: change url

    33  *

    34  * This class overrides the characterProcessing method to do Khmer character processing

    35  * and reordering (See the MS spec. for more details)

    36  *

    37  * @internal

    38  */

    39 class KhmerOpenTypeLayoutEngine : public OpenTypeLayoutEngine

    40 {

    41 public:

    42     /**

    43      * This is the main constructor. It constructs an instance of KhmerOpenTypeLayoutEngine for

    44      * a particular font, script and language. It takes the GSUB table as a parameter since

    45      * LayoutEngine::layoutEngineFactory has to read the GSUB table to know that it has an

    46      * Khmer OpenType font.

    47      *

    48      * @param fontInstance - the font

    49      * @param scriptCode - the script

    50      * @param langaugeCode - the language

    51      * @param gsubTable - the GSUB table

    52      *

    53      * @see LayoutEngine::layoutEngineFactory

    54      * @see OpenTypeLayoutEngine

    55      * @see ScriptAndLangaugeTags.h for script and language codes

    56      *

    57      * @internal

    58      */

    59     KhmerOpenTypeLayoutEngine(const LEFontInstance *fontInstance, le_int32 scriptCode, le_int32 languageCode,

    60                             le_int32 typoFlags, const GlyphSubstitutionTableHeader *gsubTable);

    61 

    62     /**

    63      * This constructor is used when the font requires a "canned" GSUB table which can't be known

    64      * until after this constructor has been invoked.

    65      *

    66      * @param fontInstance - the font

    67      * @param scriptCode - the script

    68      * @param langaugeCode - the language

    69      *

    70      * @see OpenTypeLayoutEngine

    71      * @see ScriptAndLangaugeTags.h for script and language codes

    72      *

    73      * @internal

    74      */

    75     KhmerOpenTypeLayoutEngine(const LEFontInstance *fontInstance, le_int32 scriptCode, le_int32 languageCode,

    76 			      le_int32 typoFlags);

    77 

    78     /**

    79      * The destructor, virtual for correct polymorphic invocation.

    80      *

    81      * @internal

    82      */

    83    virtual ~KhmerOpenTypeLayoutEngine();

    84 

    85     /**

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

    87      *

    88      * @stable ICU 2.8

    89      */

    90     virtual UClassID getDynamicClassID() const;

    91 

    92     /**

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

    94      *

    95      * @stable ICU 2.8

    96      */

    97     static UClassID getStaticClassID();

    98 

    99 protected:

   100 

   101     /**

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

   103      * tags to the characters, and may generate output characters which have been reordered. 

   104      * It may also split some vowels, resulting in more output characters than input characters.

   105      *

   106      * Input parameters:

   107      * @param chars - the input character context

   108      * @param offset - the index of the first character to process

   109      * @param count - the number of characters to process

   110      * @param max - the number of characters in the input context

   111      * @param rightToLeft - <code>TRUE</code> if the characters are in a right to left directional run

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

   113      *                       the auxillary data array will be set to the feature tags.

   114      *

   115      * Output parameters:

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

   117      *

   118      * @return the output character count

   119      *

   120      * @internal

   121      */

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

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

   124 

   125 };

   126 

   127 U_NAMESPACE_END

   128 #endif

   129