1 

     2 /*

     3  * HanLayoutEngine.h: OpenType processing for Han fonts.

     4  *

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

     6  */

     7 

     8 #ifndef __HANLAYOUTENGINE_H

     9 #define __HANLAYOUTENGINE_H

    10 

    11 #include "LETypes.h"

    12 #include "LEFontInstance.h"

    13 #include "LayoutEngine.h"

    14 #include "OpenTypeLayoutEngine.h"

    15 

    16 #include "GlyphSubstitutionTables.h"

    17 

    18 U_NAMESPACE_BEGIN

    19 

    20 class LEGlyphStorage;

    21 

    22 /**

    23  * This class implements OpenType layout for Han fonts. It overrides

    24  * the characerProcessing method to assign the correct OpenType feature

    25  * tags for the CJK language-specific forms.

    26  *

    27  * @internal

    28  */

    29 class HanOpenTypeLayoutEngine : public OpenTypeLayoutEngine

    30 {

    31 public:

    32     /**

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

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

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

    36      * Han OpenType font.

    37      *

    38      * @param fontInstance - the font

    39      * @param scriptCode - the script

    40      * @param langaugeCode - the language

    41      * @param gsubTable - the GSUB table

    42      *

    43      * @see LayoutEngine::layoutEngineFactory

    44      * @see OpenTypeLayoutEngine

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

    46      *

    47      * @internal

    48      */

    49     HanOpenTypeLayoutEngine(const LEFontInstance *fontInstance, le_int32 scriptCode, le_int32 languageCode,

    50                             le_int32 typoFlags, const GlyphSubstitutionTableHeader *gsubTable);

    51 

    52 

    53     /**

    54      * The destructor, virtual for correct polymorphic invocation.

    55      *

    56      * @internal

    57      */

    58     virtual ~HanOpenTypeLayoutEngine();

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

    78      * tags to the characters to generate the correct language-specific variants.

    79      *

    80      * Input parameters:

    81      * @param chars - the input character context

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

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

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

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

    86      * @param glyphStorage - the object holding the glyph storage. The char index and auxillary data arrays will be set.

    87      *

    88      * Output parameters:

    89      * @param outChars - the output character arrayt

    90      * @param charIndices - the output character index array

    91      * @param featureTags - the output feature tag array

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

    93      *

    94      * @return the output character count

    95      *

    96      * @internal

    97      */

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

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

   100 

   101 };

   102 

   103 U_NAMESPACE_END

   104 #endif