icuSources/layout/HangulLayoutEngine.h

   1
   2 /*
   3  *
   4  * (C) Copyright IBM Corp. 1998-2008 - 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      * @param success - set to an error code if the operation fails
  50      *
  51      * @see LayoutEngine::layoutEngineFactory
  52      * @see OpenTypeLayoutEngine
  53      * @see ScriptAndLangaugeTags.h for script and language codes
  54      *
  55      * @internal
  56      */
  57     HangulOpenTypeLayoutEngine(const LEFontInstance *fontInstance, le_int32 scriptCode, le_int32 languageCode,
  58                             le_int32 typoFlags, const GlyphSubstitutionTableHeader *gsubTable, LEErrorCode &success);
  59
  60     /**
  61      * This constructor is used when the font requires a "canned" GSUB table which can't be known
  62      * until after this constructor has been invoked.
  63      *
  64      * @param fontInstance - the font
  65      * @param scriptCode - the script
  66      * @param langaugeCode - the language
  67      * @param success - set to an error code if the operation fails
  68      *
  69      * @see OpenTypeLayoutEngine
  70      * @see ScriptAndLangaugeTags.h for script and language codes
  71      *
  72      * @internal
  73      */
  74     HangulOpenTypeLayoutEngine(const LEFontInstance *fontInstance, le_int32 scriptCode, le_int32 languageCode,
  75                               le_int32 typoFlags, LEErrorCode &success);
  76
  77     /**
  78      * The destructor, virtual for correct polymorphic invocation.
  79      *
  80      * @internal
  81      */
  82    virtual ~HangulOpenTypeLayoutEngine();
  83
  84     /**
  85      * ICU "poor man's RTTI", returns a UClassID for the actual class.
  86      *
  87      * @stable ICU 2.8
  88      */
  89     virtual UClassID getDynamicClassID() const;
  90
  91     /**
  92      * ICU "poor man's RTTI", returns a UClassID for this class.
  93      *
  94      * @stable ICU 2.8
  95      */
  96     static UClassID getStaticClassID();
  97
  98 protected:
  99
 100     /**
 101      * This method does Hangul OpenType character processing. It assigns the OpenType feature
 102      * tags to the characters, and may compose a character sequence into a modern Hangul syllable,
 103      * or decompose a modern Hangul syllable if it forms part of an old Hangul syllable.
 104      *
 105      * Input parameters:
 106      * @param chars - the input character context
 107      * @param offset - the index of the first character to process
 108      * @param count - the number of characters to process
 109      * @param max - the number of characters in the input context
 110      * @param rightToLeft - <code>TRUE</code> if the characters are in a right to left directional run
 111      * @param glyphStorage - the glyph storage object. The glyph and character index arrays will be set.
 112      *                       the auxillary data array will be set to the feature tags.
 113      *
 114      * Output parameters:
 115      * @param success - set to an error code if the operation fails
 116      *
 117      * @return the output character count
 118      *
 119      * @internal
 120      */
 121     virtual le_int32 characterProcessing(const LEUnicode chars[], le_int32 offset, le_int32 count, le_int32 max, le_bool rightToLeft,
 122             LEUnicode *&outChars, LEGlyphStorage &glyphStorage, LEErrorCode &success);
 123 };
 124
 125 U_NAMESPACE_END
 126 #endif
 127