1 

     2 /*

     3  *

     4  * (C) Copyright IBM Corp. 1998-2004 - All Rights Reserved

     5  *

     6  */

     7 

     8 #ifndef __GXLAYOUTENGINE_H

     9 #define __GXLAYOUTENGINE_H

    10 

    11 #include "LETypes.h"

    12 #include "LayoutEngine.h"

    13 

    14 #include "MorphTables.h"

    15 

    16 U_NAMESPACE_BEGIN

    17 

    18 class LEFontInstance;

    19 class LEGlyphStorage;

    20 

    21 /**

    22  * This class implements layout for QuickDraw GX or Apple Advanced Typograyph (AAT)

    23  * fonts. A font is a GX or AAT font if it contains a 'mort' table. See Apple's

    24  * TrueType Reference Manual (http://fonts.apple.com/TTRefMan/index.html) for details.

    25  * Information about 'mort' tables is in the chapter titled "Font Files."

    26  *

    27  * @internal

    28  */

    29 class GXLayoutEngine : public LayoutEngine

    30 {

    31 public:

    32     /**

    33      * This is the main constructor. It constructs an instance of GXLayoutEngine for

    34      * a particular font, script and language. It takes the 'mort' table as a parameter since

    35      * LayoutEngine::layoutEngineFactory has to read the 'mort' table to know that it has a

    36      * GX font.

    37      *

    38      * Note: GX and AAT fonts don't contain any script and language specific tables, so

    39      * the script and language are ignored.

    40      *

    41      * @param fontInstance - the font

    42      * @param scriptCode - the script

    43      * @param langaugeCode - the language

    44      * @param morphTable - the 'mort' table

    45      *

    46      * @see LayoutEngine::layoutEngineFactory

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

    48      *

    49      * @internal

    50      */

    51     GXLayoutEngine(const LEFontInstance *fontInstance, le_int32 scriptCode, le_int32 languageCode, const MorphTableHeader *morphTable);

    52 

    53     /**

    54      * The destructor, virtual for correct polymorphic invocation.

    55      *

    56      * @internal

    57      */

    58     virtual ~GXLayoutEngine();

    59 

    60     /**

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

    62      *

    63      * @stable ICU 2.8

    64      */

    65     virtual UClassID getDynamicClassID() const;

    66 

    67     /**

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

    69      *

    70      * @stable ICU 2.8

    71      */

    72     static UClassID getStaticClassID();

    73 

    74 protected:

    75 

    76     /**

    77      * The address of the 'mort' table

    78      *

    79      * @internal

    80      */

    81     const MorphTableHeader *fMorphTable;

    82 

    83     /**

    84      * This method does GX layout using the font's 'mort' table. It converts the

    85      * input character codes to glyph indices using mapCharsToGlyphs, and then

    86      * applies the 'mort' table.

    87      *

    88      * Input parameters:

    89      * @param chars - the input character context

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

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

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

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

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

    95      *

    96      * Output parameters:

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

    98      *

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

   100      *

   101      * @internal

   102      */

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

   104         LEGlyphStorage &glyphStorage, LEErrorCode &success);

   105 

   106     /**

   107      * This method adjusts the glyph positions using the font's

   108      * 'kern', 'trak', 'bsln', 'opbd' and 'just' tables.

   109      *

   110      * Input parameters:

   111      * @param glyphStorage - the object holding the glyph storage. The positions will be updated as needed.

   112      *

   113      * Output parameters:

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

   115      *

   116      * @internal

   117      */

   118     virtual void adjustGlyphPositions(const LEUnicode chars[], le_int32 offset, le_int32 count, le_bool reverse,

   119                                       LEGlyphStorage &glyphStorage, LEErrorCode &success);

   120 

   121 };

   122 

   123 U_NAMESPACE_END

   124 #endif

   125