icuSources/layout/HangulLayoutEngine.h

   1
   2 /*
   3  *
   4  * (C) Copyright IBM Corp. 1998-2006 - All Rights Reserved
   5  *
   6  */
   7
   8 #ifndef __HANGULAYOUTENGINE_H
   9 #define __HANGULAYOUTENGINE_H
  10
  11 #include "LETypes.h"
  12 #include "LEFontInstance.h"
  13 #include "LEGlyphFilter.h"
  14 #include "LayoutEngine.h"
  15 #include "OpenTypeLayoutEngine.h"
  16
  17 #include "GlyphSubstitutionTables.h"
  18 #include "GlyphDefinitionTables.h"
  19 #include "GlyphPositioningTables.h"
  20
  21 U_NAMESPACE_BEGIN
  22
  23 class MPreFixups;
  24 class LEGlyphStorage;
  25
  26 /**
  27  * This class implements OpenType layout for Old Hangul OpenType fonts, as
  28  * specified by Microsoft in "Creating and Supporting OpenType Fonts for
  29  * The Korean Hangul Script" (http://www.microsoft.com/typography/otfntdev/hangulot/default.htm)
  30  *
  31  * This class overrides the characterProcessing method to do Hangul character processing.
  32  * (See the MS spec. for more details)
  33  *
  34  * @internal
  35  */
  36 class HangulOpenTypeLayoutEngine : public OpenTypeLayoutEngine
  37 {
  38 public:
  39     /**
  40      * This is the main constructor. It constructs an instance of HangulOpenTypeLayoutEngine for
  41      * a particular font, script and language. It takes the GSUB table as a parameter since
  42      * LayoutEngine::layoutEngineFactory has to read the GSUB table to know that it has an
  43      * Hangul OpenType font.
  44      *
  45      * @param fontInstance - the font
  46      * @param scriptCode - the script
  47      * @param langaugeCode - the language
  48      * @param gsubTable - the GSUB table
  49      *
  50      * @see LayoutEngine::layoutEngineFactory
  51      * @see OpenTypeLayoutEngine
  52      * @see ScriptAndLangaugeTags.h for script and language codes
  53      *
  54      * @internal
  55      */
  56     HangulOpenTypeLayoutEngine(const LEFontInstance *fontInstance, le_int32 scriptCode, le_int32 languageCode,
  57                             le_int32 typoFlags, const GlyphSubstitutionTableHeader *gsubTable);
  58
  59     /**
  60      * This constructor is used when the font requires a "canned" GSUB table which can't be known
  61      * until after this constructor has been invoked.
  62      *
  63      * @param fontInstance - the font
  64      * @param scriptCode - the script
  65      * @param langaugeCode - the language
  66      *
  67      * @see OpenTypeLayoutEngine
  68      * @see ScriptAndLangaugeTags.h for script and language codes
  69      *
  70      * @internal
  71      */
  72     HangulOpenTypeLayoutEngine(const LEFontInstance *fontInstance, le_int32 scriptCode, le_int32 languageCode,
  73                               le_int32 typoFlags);
  74
  75     /**
  76      * The destructor, virtual for correct polymorphic invocation.
  77      *
  78      * @internal
  79      */
  80    virtual ~HangulOpenTypeLayoutEngine();
  81
  82     /**
  83      * ICU "poor man's RTTI", returns a UClassID for the actual class.
  84      *
  85      * @stable ICU 2.8
  86      */
  87     virtual UClassID getDynamicClassID() const;
  88
  89     /**
  90      * ICU "poor man's RTTI", returns a UClassID for this class.
  91      *
  92      * @stable ICU 2.8
  93      */
  94     static UClassID getStaticClassID();
  95
  96 protected:
  97
  98     /**
  99      * This method does Hangul OpenType character processing. It assigns the OpenType feature
 100      * tags to the characters, and may compose a character sequence into a modern Hangul syllable,
 101      * or decompose a modern Hangul syllable if it forms part of an old Hangul syllable.
 102      *
 103      * Input parameters:
 104      * @param chars - the input character context
 105      * @param offset - the index of the first character to process
 106      * @param count - the number of characters to process
 107      * @param max - the number of characters in the input context
 108      * @param rightToLeft - <code>TRUE</code> if the characters are in a right to left directional run
 109      * @param glyphStorage - the glyph storage object. The glyph and character index arrays will be set.
 110      *                       the auxillary data array will be set to the feature tags.
 111      *
 112      * Output parameters:
 113      * @param success - set to an error code if the operation fails
 114      *
 115      * @return the output character count
 116      *
 117      * @internal
 118      */
 119     virtual le_int32 characterProcessing(const LEUnicode chars[], le_int32 offset, le_int32 count, le_int32 max, le_bool rightToLeft,
 120             LEUnicode *&outChars, LEGlyphStorage &glyphStorage, LEErrorCode &success);
 121 };
 122
 123 U_NAMESPACE_END
 124 #endif
 125