icuSources/layout/HanLayoutEngine.h

   1
   2 /*
   3  * HanLayoutEngine.h: OpenType processing for Han fonts.
   4  *
   5  * (C) Copyright IBM Corp. 1998-2004 - 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                             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