ftxgsub.h

神龙卡开发原代码

/*******************************************************************
 *
 *  ftxgsub.h
 *
 *    TrueType Open GSUB table support
 *
 *  Copyright 1996-1999 by
 *  David Turner, Robert Wilhelm, and Werner Lemberg.
 *
 *  This file is part of the FreeType project, and may only be used
 *  modified and distributed under the terms of the FreeType project
 *  license, LICENSE.TXT.  By continuing to use, modify, or distribute
 *  this file you indicate that you have read the license and
 *  understand and accept it fully.
 *
 ******************************************************************/

#ifndef FTXOPEN_H
#error "Don't include this file! Use ftxopen.h instead."
#endif

#ifndef FTXGSUB_H
#define FTXGSUB_H

#ifdef __cplusplus
extern "C" {
#endif

#define TTO_Err_Invalid_GSUB_SubTable_Format  0x1010
#define TTO_Err_Invalid_GSUB_SubTable         0x1011


/* Lookup types for glyph substitution */

#define GSUB_LOOKUP_SINGLE     1
#define GSUB_LOOKUP_MULTIPLE   2
#define GSUB_LOOKUP_ALTERNATE  3
#define GSUB_LOOKUP_LIGATURE   4
#define GSUB_LOOKUP_CONTEXT    5
#define GSUB_LOOKUP_CHAIN      6


/* Use this if a feature applies to all glyphs */

#define ALL_GLYPHS  0xFFFF


  /* A pointer to a function which selects the alternate glyph.  `pos' is
     the position of the glyph with index `glyphID', `num_alternates'
     gives the number of alternates in the `alternates' array.  `data'
     points to the user-defined structure specified during a call to
     TT_GSUB_Register_Alternate_Function().  The function must return an
     index into the `alternates' array.                                   */

  typedef TT_UShort  (*TTO_AltFunction)(TT_ULong    pos,
                                        TT_UShort   glyphID,
                                        TT_UShort   num_alternates,
                                        TT_UShort*  alternates,
                                        void*       data );


  struct  TTO_GSUBHeader_
  {
    TT_Bool          loaded;
    TT_ULong         offset;

    TT_Fixed         Version;

    TTO_ScriptList   ScriptList;
    TTO_FeatureList  FeatureList;
    TTO_LookupList   LookupList;

    TTO_GDEFHeader*  gdef;

    /* the next two fields are used for an alternate substitution callback
       function to select the proper alternate glyph.                      */

    TTO_AltFunction  alt;
    void*            data;
  };

  typedef struct TTO_GSUBHeader_  TTO_GSUBHeader;


  /* LookupType 1 */

  struct  TTO_SingleSubstFormat1_
  {
    TT_Short  DeltaGlyphID;             /* constant added to get
                                           substitution glyph index */
  };

  typedef struct TTO_SingleSubstFormat1_  TTO_SingleSubstFormat1;


  struct  TTO_SingleSubstFormat2_
  {
    TT_UShort   GlyphCount;             /* number of glyph IDs in
                                           Substitute array              */
    TT_UShort*  Substitute;             /* array of substitute glyph IDs */
  };

  typedef struct TTO_SingleSubstFormat2_  TTO_SingleSubstFormat2;


  struct  TTO_SingleSubst_
  {
    TT_UShort     SubstFormat;          /* 1 or 2         */
    TTO_Coverage  Coverage;             /* Coverage table */

    union
    {
      TTO_SingleSubstFormat1  ssf1;
      TTO_SingleSubstFormat2  ssf2;
    } ssf;
  };

  typedef struct TTO_SingleSubst_  TTO_SingleSubst;


  /* LookupType 2 */

  struct  TTO_Sequence_
  {
    TT_UShort   GlyphCount;             /* number of glyph IDs in the
                                           Substitute array           */
    TT_UShort*  Substitute;             /* string of glyph IDs to
                                           substitute                 */
  };

  typedef struct TTO_Sequence_  TTO_Sequence;


  struct  TTO_MultipleSubst_
  {
    TT_UShort      SubstFormat;         /* always 1                  */
    TTO_Coverage   Coverage;            /* Coverage table            */
    TT_UShort      SequenceCount;       /* number of Sequence tables */
    TTO_Sequence*  Sequence;            /* array of Sequence tables  */
  };

  typedef struct TTO_MultipleSubst_  TTO_MultipleSubst;


  /* LookupType 3 */

  struct  TTO_AlternateSet_
  {
    TT_UShort   GlyphCount;             /* number of glyph IDs in the
                                           Alternate array              */
    TT_UShort*  Alternate;              /* array of alternate glyph IDs */
  };

  typedef struct TTO_AlternateSet_  TTO_AlternateSet;


  struct  TTO_AlternateSubst_
  {
    TT_UShort          SubstFormat;     /* always 1                      */
    TTO_Coverage       Coverage;        /* Coverage table                */
    TT_UShort          AlternateSetCount;
                                        /* number of AlternateSet tables */
    TTO_AlternateSet*  AlternateSet;    /* array of AlternateSet tables  */
  };

  typedef struct TTO_AlternateSubst_  TTO_AlternateSubst;


  /* LookupType 4 */

  struct  TTO_Ligature_
  {
    TT_UShort   LigGlyph;               /* glyphID of ligature
                                           to substitute                    */
    TT_UShort   ComponentCount;         /* number of components in ligature */
    TT_UShort*  Component;              /* array of component glyph IDs     */
  };

  typedef struct TTO_Ligature_  TTO_Ligature;


  struct  TTO_LigatureSet_
  {
    TT_UShort      LigatureCount;       /* number of Ligature tables */
    TTO_Ligature*  Ligature;            /* array of Ligature tables  */
  };

  typedef struct TTO_LigatureSet_  TTO_LigatureSet;


  struct  TTO_LigatureSubst_
  {
    TT_UShort         SubstFormat;      /* always 1                     */
    TTO_Coverage      Coverage;         /* Coverage table               */
    TT_UShort         LigatureSetCount; /* number of LigatureSet tables */
    TTO_LigatureSet*  LigatureSet;      /* array of LigatureSet tables  */
  };

  typedef struct TTO_LigatureSubst_  TTO_LigatureSubst;


  /* needed by both lookup type 5 and 6 */

  struct  TTO_SubstLookupRecord_
  {
    TT_UShort  SequenceIndex;           /* index into current
                                           glyph sequence               */
    TT_UShort  LookupListIndex;         /* Lookup to apply to that pos. */
  };

  typedef struct TTO_SubstLookupRecord_  TTO_SubstLookupRecord;


  /* LookupType 5 */

  struct  TTO_SubRule_
  {
    TT_UShort               GlyphCount; /* total number of input glyphs */
    TT_UShort               SubstCount; /* number of SubstLookupRecord
                                           tables                       */
    TT_UShort*              Input;      /* array of input glyph IDs     */
    TTO_SubstLookupRecord*  SubstLookupRecord;
                                        /* array of SubstLookupRecord
                                           tables                       */
  };

  typedef struct TTO_SubRule_  TTO_SubRule;


  struct  TTO_SubRuleSet_
  {
    TT_UShort     SubRuleCount;         /* number of SubRule tables */
    TTO_SubRule*  SubRule;              /* array of SubRule tables  */
  };

  typedef struct TTO_SubRuleSet_  TTO_SubRuleSet;


  struct  TTO_ContextSubstFormat1_
  {
    TTO_Coverage     Coverage;          /* Coverage table              */
    TT_UShort        SubRuleSetCount;   /* number of SubRuleSet tables */
    TTO_SubRuleSet*  SubRuleSet;        /* array of SubRuleSet tables  */
  };

  typedef struct TTO_ContextSubstFormat1_  TTO_ContextSubstFormat1;


  struct  TTO_SubClassRule_
  {
    TT_UShort               GlyphCount; /* total number of context classes */
    TT_UShort               SubstCount; /* number of SubstLookupRecord
                                           tables                          */
    TT_UShort*              Class;      /* array of classes                */
    TTO_SubstLookupRecord*  SubstLookupRecord;
                                        /* array of SubstLookupRecord
                                           tables                          */
  };

  typedef struct TTO_SubClassRule_  TTO_SubClassRule;


  struct  TTO_SubClassSet_
  {
    TT_UShort          SubClassRuleCount;
                                        /* number of SubClassRule tables */
    TTO_SubClassRule*  SubClassRule;    /* array of SubClassRule tables  */
  };

  typedef struct TTO_SubClassSet_  TTO_SubClassSet;


  /* The `MaxContextLength' field is not defined in the TTO specification
     but simplifies the implementation of this format.  It holds the
     maximal context length used in the context rules.                    */

  struct  TTO_ContextSubstFormat2_
  {
    TT_UShort            MaxContextLength;
                                        /* maximal context length       */
    TTO_Coverage         Coverage;      /* Coverage table               */
    TTO_ClassDefinition  ClassDef;      /* ClassDef table               */
    TT_UShort            SubClassSetCount;
                                        /* number of SubClassSet tables */
    TTO_SubClassSet*     SubClassSet;   /* array of SubClassSet tables  */
  };

  typedef struct TTO_ContextSubstFormat2_  TTO_ContextSubstFormat2;


  struct  TTO_ContextSubstFormat3_