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      1 
      2 /*
      3  * HanLayoutEngine.h: OpenType processing for Han fonts.
      4  *
      5  * (C) Copyright IBM Corp. 1998-2008 - 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      * @param success - set to an error code if the operation fails
     43      *
     44      * @see LayoutEngine::layoutEngineFactory
     45      * @see OpenTypeLayoutEngine
     46      * @see ScriptAndLangaugeTags.h for script and language codes
     47      *
     48      * @internal
     49      */
     50     HanOpenTypeLayoutEngine(const LEFontInstance *fontInstance, le_int32 scriptCode, le_int32 languageCode,
     51                             le_int32 typoFlags, const GlyphSubstitutionTableHeader *gsubTablem, LEErrorCode &success);
     52 
     53 
     54     /**
     55      * The destructor, virtual for correct polymorphic invocation.
     56      *
     57      * @internal
     58      */
     59     virtual ~HanOpenTypeLayoutEngine();
     60 
     61     /**
     62      * ICU "poor man's RTTI", returns a UClassID for the actual class.
     63      *
     64      * @stable ICU 2.8
     65      */
     66     virtual UClassID getDynamicClassID() const;
     67 
     68     /**
     69      * ICU "poor man's RTTI", returns a UClassID for this class.
     70      *
     71      * @stable ICU 2.8
     72      */
     73     static UClassID getStaticClassID();
     74 
     75 protected:
     76 
     77     /**
     78      * This method does Han OpenType character processing. It assigns the OpenType feature
     79      * tags to the characters to generate the correct language-specific variants.
     80      *
     81      * Input parameters:
     82      * @param chars - the input character context
     83      * @param offset - the index of the first character to process
     84      * @param count - the number of characters to process
     85      * @param max - the number of characters in the input context
     86      * @param rightToLeft - <code>TRUE</code> if the characters are in a right to left directional run
     87      * @param glyphStorage - the object holding the glyph storage. The char index and auxillary data arrays will be set.
     88      *
     89      * Output parameters:
     90      * @param outChars - the output character arrayt
     91      * @param charIndices - the output character index array
     92      * @param featureTags - the output feature tag array
     93      * @param success - set to an error code if the operation fails
     94      *
     95      * @return the output character count
     96      *
     97      * @internal
     98      */
     99     virtual le_int32 characterProcessing(const LEUnicode chars[], le_int32 offset, le_int32 count, le_int32 max, le_bool rightToLeft,
    100             LEUnicode *&outChars, LEGlyphStorage &glyphStorage, LEErrorCode &success);
    101 
    102 };
    103 
    104 U_NAMESPACE_END
    105 #endif
    106