icuSources/layout/KhmerLayoutEngine.h

   1 /*
   2  *
   3  * (C) Copyright IBM Corp. 1998-2016 - All Rights Reserved
   4  *
   5  * This file is a modification of the ICU file IndicLayoutEngine.h
   6  * by Jens Herden and Javier Sola for Khmer language
   7  *
   8  */
   9
  10 #ifndef __KHMERLAYOUTENGINE_H
  11 #define __KHMERLAYOUTENGINE_H
  12
  13 #include "LETypes.h"
  14 #include "LEFontInstance.h"
  15 #include "LEGlyphFilter.h"
  16 #include "LayoutEngine.h"
  17 #include "OpenTypeLayoutEngine.h"
  18
  19 #include "GlyphSubstitutionTables.h"
  20 #include "GlyphDefinitionTables.h"
  21 #include "GlyphPositioningTables.h"
  22
  23 U_NAMESPACE_BEGIN
  24
  25 class MPreFixups;
  26 class LEGlyphStorage;
  27
  28 /**
  29  * This class implements OpenType layout for Khmer OpenType fonts, as
  30  * specified by Microsoft in "Creating and Supporting OpenType Fonts for
  31  * Khmer Scripts" (http://www.microsoft.com/typography/otspec/indicot/default.htm) TODO: change url
  32  *
  33  * This class overrides the characterProcessing method to do Khmer character processing
  34  * and reordering (See the MS spec. for more details)
  35  *
  36  * @internal
  37  */
  38 class KhmerOpenTypeLayoutEngine : public OpenTypeLayoutEngine
  39 {
  40 public:
  41     /**
  42      * This is the main constructor. It constructs an instance of KhmerOpenTypeLayoutEngine for
  43      * a particular font, script and language. It takes the GSUB table as a parameter since
  44      * LayoutEngine::layoutEngineFactory has to read the GSUB table to know that it has an
  45      * Khmer OpenType font.
  46      *
  47      * @param fontInstance - the font
  48      * @param scriptCode - the script
  49      * @param langaugeCode - the language
  50      * @param gsubTable - the GSUB table
  51      * @param success - set to an error code if the operation fails
  52      *
  53      * @see LayoutEngine::layoutEngineFactory
  54      * @see OpenTypeLayoutEngine
  55      * @see ScriptAndLangaugeTags.h for script and language codes
  56      *
  57      * @internal
  58      */
  59     KhmerOpenTypeLayoutEngine(const LEFontInstance *fontInstance, le_int32 scriptCode, le_int32 languageCode,
  60                             le_int32 typoFlags, const LEReferenceTo<GlyphSubstitutionTableHeader> &gsubTable, LEErrorCode &success);
  61
  62     /**
  63      * This constructor is used when the font requires a "canned" GSUB table which can't be known
  64      * until after this constructor has been invoked.
  65      *
  66      * @param fontInstance - the font
  67      * @param scriptCode - the script
  68      * @param langaugeCode - the language
  69      * @param success - set to an error code if the operation fails
  70      *
  71      * @see OpenTypeLayoutEngine
  72      * @see ScriptAndLangaugeTags.h for script and language codes
  73      *
  74      * @internal
  75      */
  76     KhmerOpenTypeLayoutEngine(const LEFontInstance *fontInstance, le_int32 scriptCode, le_int32 languageCode,
  77                               le_int32 typoFlags, LEErrorCode &success);
  78
  79     /**
  80      * The destructor, virtual for correct polymorphic invocation.
  81      *
  82      * @internal
  83      */
  84    virtual ~KhmerOpenTypeLayoutEngine();
  85
  86     /**
  87      * ICU "poor man's RTTI", returns a UClassID for the actual class.
  88      *
  89      * @deprecated ICU 54. See {@link icu::LayoutEngine}
  90      */
  91     virtual UClassID getDynamicClassID() const;
  92
  93     /**
  94      * ICU "poor man's RTTI", returns a UClassID for this class.
  95      *
  96      * @deprecated ICU 54. See {@link icu::LayoutEngine}
  97      */
  98     static UClassID getStaticClassID();
  99
 100 protected:
 101
 102     /**
 103      * This method does Khmer OpenType character processing. It assigns the OpenType feature
 104      * tags to the characters, and may generate output characters which have been reordered.
 105      * It may also split some vowels, resulting in more output characters than input characters.
 106      *
 107      * Input parameters:
 108      * @param chars - the input character context
 109      * @param offset - the index of the first character to process
 110      * @param count - the number of characters to process
 111      * @param max - the number of characters in the input context
 112      * @param rightToLeft - <code>TRUE</code> if the characters are in a right to left directional run
 113      * @param glyphStorage - the glyph storage object. The glyph and character index arrays will be set.
 114      *                       the auxillary data array will be set to the feature tags.
 115      *
 116      * Output parameters:
 117      * @param success - set to an error code if the operation fails
 118      *
 119      * @return the output character count
 120      *
 121      * @internal
 122      */
 123     virtual le_int32 characterProcessing(const LEUnicode chars[], le_int32 offset, le_int32 count, le_int32 max, le_bool rightToLeft,
 124             LEUnicode *&outChars, LEGlyphStorage &glyphStorage, LEErrorCode &success);
 125
 126 };
 127
 128 U_NAMESPACE_END
 129 #endif