1 

     2 /*

     3  *

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

     5  *

     6  */

     7 

     8 #ifndef __THAILAYOUTENGINE_H

     9 #define __THAILAYOUTENGINE_H

    10 

    11 #include "LETypes.h"

    12 #include "LEFontInstance.h"

    13 #include "LayoutEngine.h"

    14 

    15 #include "ThaiShaping.h"

    16 

    17 U_NAMESPACE_BEGIN

    18 

    19 class LEGlyphStorage;

    20 

    21 /**

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

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

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

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

    26  *

    27  * @internal

    28  */

    29 class ThaiLayoutEngine : public LayoutEngine

    30 {

    31 public:

    32     /**

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

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

    35      * and fErrorChar. (see below)

    36      *

    37      * @param fontInstance - the font

    38      * @param scriptCode - the script

    39      * @param languageCode - the language

    40      *

    41      * @see LEFontInstance

    42      * @see ScriptAndLanguageTags.h for script and language codes

    43      *

    44      * @internal

    45      */

    46     ThaiLayoutEngine(const LEFontInstance *fontInstance, le_int32 scriptCode, le_int32 languageCode, le_int32 typoFlags);

    47 

    48     /**

    49      * The destructor, virtual for correct polymorphic invocation.

    50      *

    51      * @internal

    52      */

    53     virtual ~ThaiLayoutEngine();

    54 

    55     /**

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

    57      *

    58      * @stable ICU 2.8

    59      */

    60     virtual UClassID getDynamicClassID() const;

    61 

    62     /**

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

    64      *

    65      * @stable ICU 2.8

    66      */

    67     static UClassID getStaticClassID();

    68 

    69 protected:

    70     /**

    71      * A small integer indicating which Thai encoding

    72      * the font uses.

    73      *

    74      * @see ThaiShaping

    75      *

    76      * @internal

    77      */

    78     le_uint8 fGlyphSet;

    79 

    80     /**

    81      * The character used as a base for vowels and

    82      * tone marks that are out of sequence. Usually

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

    84      * display it.

    85      *

    86      * @see ThaiShaping

    87      *

    88      * @internal

    89      */

    90     LEUnicode fErrorChar;

    91 

    92     /**

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

    94      * generate the correct contextual character codes, and then calls

    95      * mapCharsToGlyphs to generate the glyph indices.

    96      *

    97      * Input parameters:

    98      * @param chars - the input character context

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

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

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

   102      * @param rightToLeft - <code>TRUE</code> if the text is in a right to left directional run

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

   104      *

   105      * Output parameters:

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

   107      *

   108      * @return the number of glyphs in the glyph index array

   109      *

   110      * @see ThaiShaping

   111      *

   112      * @internal

   113      */

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

   115         LEGlyphStorage &glyphStorage, LEErrorCode &success);

   116 

   117 };

   118 

   119 U_NAMESPACE_END

   120 #endif

   121