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576 lines
20 KiB
576 lines
20 KiB
/*******************************************************************
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*
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* ftxgsub.h
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*
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* TrueType Open GSUB table support
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*
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* Copyright 1996-2000 by
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* David Turner, Robert Wilhelm, and Werner Lemberg.
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*
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* This file is part of the FreeType project, and may only be used
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* modified and distributed under the terms of the FreeType project
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* license, LICENSE.TXT. By continuing to use, modify, or distribute
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* this file you indicate that you have read the license and
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* understand and accept it fully.
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*
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******************************************************************/
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#ifndef FTXOPEN_H
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#error "Don't include this file! Use ftxopen.h instead."
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#endif
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#ifndef FTXGSUB_H
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#define FTXGSUB_H
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#ifdef __cplusplus
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extern "C" {
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#endif
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#define TTO_Err_Invalid_GSUB_SubTable_Format 0x1010
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#define TTO_Err_Invalid_GSUB_SubTable 0x1011
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/* Lookup types for glyph substitution */
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#define GSUB_LOOKUP_SINGLE 1
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#define GSUB_LOOKUP_MULTIPLE 2
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#define GSUB_LOOKUP_ALTERNATE 3
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#define GSUB_LOOKUP_LIGATURE 4
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#define GSUB_LOOKUP_CONTEXT 5
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#define GSUB_LOOKUP_CHAIN 6
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#define GSUB_LOOKUP_EXTENSION 7
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/* Use this if a feature applies to all glyphs */
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#define ALL_GLYPHS 0xFFFF
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/* A pointer to a function which selects the alternate glyph. `pos' is
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the position of the glyph with index `glyphID', `num_alternates'
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gives the number of alternates in the `alternates' array. `data'
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points to the user-defined structure specified during a call to
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TT_GSUB_Register_Alternate_Function(). The function must return an
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index into the `alternates' array. */
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typedef FT_UShort (*TTO_AltFunction)(FT_ULong pos,
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FT_UShort glyphID,
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FT_UShort num_alternates,
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FT_UShort* alternates,
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void* data );
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struct TTO_GSUBHeader_
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{
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FT_Memory memory;
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FT_ULong offset;
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FT_Fixed Version;
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TTO_ScriptList ScriptList;
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TTO_FeatureList FeatureList;
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TTO_LookupList LookupList;
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TTO_GDEFHeader* gdef;
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/* the next two fields are used for an alternate substitution callback
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function to select the proper alternate glyph. */
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TTO_AltFunction altfunc;
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void* data;
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};
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typedef struct TTO_GSUBHeader_ TTO_GSUBHeader;
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typedef struct TTO_GSUBHeader_* TTO_GSUB;
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/* LookupType 1 */
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struct TTO_SingleSubstFormat1_
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{
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FT_Short DeltaGlyphID; /* constant added to get
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substitution glyph index */
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};
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typedef struct TTO_SingleSubstFormat1_ TTO_SingleSubstFormat1;
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struct TTO_SingleSubstFormat2_
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{
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FT_UShort GlyphCount; /* number of glyph IDs in
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Substitute array */
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FT_UShort* Substitute; /* array of substitute glyph IDs */
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};
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typedef struct TTO_SingleSubstFormat2_ TTO_SingleSubstFormat2;
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struct TTO_SingleSubst_
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{
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FT_UShort SubstFormat; /* 1 or 2 */
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TTO_Coverage Coverage; /* Coverage table */
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union
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{
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TTO_SingleSubstFormat1 ssf1;
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TTO_SingleSubstFormat2 ssf2;
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} ssf;
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};
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typedef struct TTO_SingleSubst_ TTO_SingleSubst;
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/* LookupType 2 */
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struct TTO_Sequence_
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{
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FT_UShort GlyphCount; /* number of glyph IDs in the
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Substitute array */
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FT_UShort* Substitute; /* string of glyph IDs to
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substitute */
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};
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typedef struct TTO_Sequence_ TTO_Sequence;
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struct TTO_MultipleSubst_
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{
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FT_UShort SubstFormat; /* always 1 */
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TTO_Coverage Coverage; /* Coverage table */
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FT_UShort SequenceCount; /* number of Sequence tables */
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TTO_Sequence* Sequence; /* array of Sequence tables */
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};
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typedef struct TTO_MultipleSubst_ TTO_MultipleSubst;
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/* LookupType 3 */
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struct TTO_AlternateSet_
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{
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FT_UShort GlyphCount; /* number of glyph IDs in the
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Alternate array */
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FT_UShort* Alternate; /* array of alternate glyph IDs */
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};
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typedef struct TTO_AlternateSet_ TTO_AlternateSet;
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struct TTO_AlternateSubst_
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{
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FT_UShort SubstFormat; /* always 1 */
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TTO_Coverage Coverage; /* Coverage table */
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FT_UShort AlternateSetCount;
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/* number of AlternateSet tables */
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TTO_AlternateSet* AlternateSet; /* array of AlternateSet tables */
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};
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typedef struct TTO_AlternateSubst_ TTO_AlternateSubst;
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/* LookupType 4 */
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struct TTO_Ligature_
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{
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FT_UShort LigGlyph; /* glyphID of ligature
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to substitute */
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FT_UShort ComponentCount; /* number of components in ligature */
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FT_UShort* Component; /* array of component glyph IDs */
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};
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typedef struct TTO_Ligature_ TTO_Ligature;
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struct TTO_LigatureSet_
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{
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FT_UShort LigatureCount; /* number of Ligature tables */
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TTO_Ligature* Ligature; /* array of Ligature tables */
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};
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typedef struct TTO_LigatureSet_ TTO_LigatureSet;
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struct TTO_LigatureSubst_
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{
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FT_UShort SubstFormat; /* always 1 */
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TTO_Coverage Coverage; /* Coverage table */
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FT_UShort LigatureSetCount; /* number of LigatureSet tables */
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TTO_LigatureSet* LigatureSet; /* array of LigatureSet tables */
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};
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typedef struct TTO_LigatureSubst_ TTO_LigatureSubst;
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/* needed by both lookup type 5 and 6 */
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struct TTO_SubstLookupRecord_
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{
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FT_UShort SequenceIndex; /* index into current
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glyph sequence */
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FT_UShort LookupListIndex; /* Lookup to apply to that pos. */
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};
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typedef struct TTO_SubstLookupRecord_ TTO_SubstLookupRecord;
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/* LookupType 5 */
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struct TTO_SubRule_
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{
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FT_UShort GlyphCount; /* total number of input glyphs */
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FT_UShort SubstCount; /* number of SubstLookupRecord
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tables */
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FT_UShort* Input; /* array of input glyph IDs */
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TTO_SubstLookupRecord* SubstLookupRecord;
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/* array of SubstLookupRecord
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tables */
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};
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typedef struct TTO_SubRule_ TTO_SubRule;
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struct TTO_SubRuleSet_
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{
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FT_UShort SubRuleCount; /* number of SubRule tables */
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TTO_SubRule* SubRule; /* array of SubRule tables */
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};
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typedef struct TTO_SubRuleSet_ TTO_SubRuleSet;
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struct TTO_ContextSubstFormat1_
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{
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TTO_Coverage Coverage; /* Coverage table */
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FT_UShort SubRuleSetCount; /* number of SubRuleSet tables */
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TTO_SubRuleSet* SubRuleSet; /* array of SubRuleSet tables */
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};
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typedef struct TTO_ContextSubstFormat1_ TTO_ContextSubstFormat1;
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struct TTO_SubClassRule_
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{
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FT_UShort GlyphCount; /* total number of context classes */
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FT_UShort SubstCount; /* number of SubstLookupRecord
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tables */
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FT_UShort* Class; /* array of classes */
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TTO_SubstLookupRecord* SubstLookupRecord;
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/* array of SubstLookupRecord
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tables */
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};
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typedef struct TTO_SubClassRule_ TTO_SubClassRule;
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struct TTO_SubClassSet_
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{
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FT_UShort SubClassRuleCount;
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/* number of SubClassRule tables */
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TTO_SubClassRule* SubClassRule; /* array of SubClassRule tables */
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};
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typedef struct TTO_SubClassSet_ TTO_SubClassSet;
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/* The `MaxContextLength' field is not defined in the TTO specification
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but simplifies the implementation of this format. It holds the
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maximal context length used in the context rules. */
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struct TTO_ContextSubstFormat2_
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{
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FT_UShort MaxContextLength;
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/* maximal context length */
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TTO_Coverage Coverage; /* Coverage table */
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TTO_ClassDefinition ClassDef; /* ClassDef table */
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FT_UShort SubClassSetCount;
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/* number of SubClassSet tables */
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TTO_SubClassSet* SubClassSet; /* array of SubClassSet tables */
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};
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typedef struct TTO_ContextSubstFormat2_ TTO_ContextSubstFormat2;
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struct TTO_ContextSubstFormat3_
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{
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FT_UShort GlyphCount; /* number of input glyphs */
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FT_UShort SubstCount; /* number of SubstLookupRecords */
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TTO_Coverage* Coverage; /* array of Coverage tables */
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TTO_SubstLookupRecord* SubstLookupRecord;
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/* array of substitution lookups */
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};
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typedef struct TTO_ContextSubstFormat3_ TTO_ContextSubstFormat3;
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struct TTO_ContextSubst_
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{
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FT_UShort SubstFormat; /* 1, 2, or 3 */
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union
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{
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TTO_ContextSubstFormat1 csf1;
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TTO_ContextSubstFormat2 csf2;
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TTO_ContextSubstFormat3 csf3;
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} csf;
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};
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typedef struct TTO_ContextSubst_ TTO_ContextSubst;
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/* LookupType 6 */
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struct TTO_ChainSubRule_
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{
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FT_UShort BacktrackGlyphCount;
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/* total number of backtrack glyphs */
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FT_UShort* Backtrack; /* array of backtrack glyph IDs */
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FT_UShort InputGlyphCount;
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/* total number of input glyphs */
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FT_UShort* Input; /* array of input glyph IDs */
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FT_UShort LookaheadGlyphCount;
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/* total number of lookahead glyphs */
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FT_UShort* Lookahead; /* array of lookahead glyph IDs */
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FT_UShort SubstCount; /* number of SubstLookupRecords */
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TTO_SubstLookupRecord* SubstLookupRecord;
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/* array of SubstLookupRecords */
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};
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typedef struct TTO_ChainSubRule_ TTO_ChainSubRule;
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struct TTO_ChainSubRuleSet_
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{
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FT_UShort ChainSubRuleCount;
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/* number of ChainSubRule tables */
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TTO_ChainSubRule* ChainSubRule; /* array of ChainSubRule tables */
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};
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typedef struct TTO_ChainSubRuleSet_ TTO_ChainSubRuleSet;
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struct TTO_ChainContextSubstFormat1_
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{
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TTO_Coverage Coverage; /* Coverage table */
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FT_UShort ChainSubRuleSetCount;
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/* number of ChainSubRuleSet tables */
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TTO_ChainSubRuleSet* ChainSubRuleSet;
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/* array of ChainSubRuleSet tables */
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};
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typedef struct TTO_ChainContextSubstFormat1_ TTO_ChainContextSubstFormat1;
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struct TTO_ChainSubClassRule_
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{
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FT_UShort BacktrackGlyphCount;
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/* total number of backtrack
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classes */
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FT_UShort* Backtrack; /* array of backtrack classes */
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FT_UShort InputGlyphCount;
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/* total number of context classes */
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FT_UShort* Input; /* array of context classes */
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FT_UShort LookaheadGlyphCount;
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/* total number of lookahead
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classes */
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FT_UShort* Lookahead; /* array of lookahead classes */
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FT_UShort SubstCount; /* number of SubstLookupRecords */
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TTO_SubstLookupRecord* SubstLookupRecord;
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/* array of substitution lookups */
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};
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typedef struct TTO_ChainSubClassRule_ TTO_ChainSubClassRule;
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struct TTO_ChainSubClassSet_
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{
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FT_UShort ChainSubClassRuleCount;
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/* number of ChainSubClassRule
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tables */
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TTO_ChainSubClassRule* ChainSubClassRule;
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/* array of ChainSubClassRule
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tables */
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};
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typedef struct TTO_ChainSubClassSet_ TTO_ChainSubClassSet;
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/* The `MaxXXXLength' fields are not defined in the TTO specification
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but simplifies the implementation of this format. It holds the
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maximal context length used in the specific context rules. */
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struct TTO_ChainContextSubstFormat2_
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{
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TTO_Coverage Coverage; /* Coverage table */
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FT_UShort MaxBacktrackLength;
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/* maximal backtrack length */
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TTO_ClassDefinition BacktrackClassDef;
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/* BacktrackClassDef table */
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FT_UShort MaxInputLength;
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/* maximal input length */
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TTO_ClassDefinition InputClassDef;
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/* InputClassDef table */
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FT_UShort MaxLookaheadLength;
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/* maximal lookahead length */
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TTO_ClassDefinition LookaheadClassDef;
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/* LookaheadClassDef table */
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FT_UShort ChainSubClassSetCount;
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/* number of ChainSubClassSet
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tables */
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TTO_ChainSubClassSet* ChainSubClassSet;
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/* array of ChainSubClassSet
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tables */
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};
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typedef struct TTO_ChainContextSubstFormat2_ TTO_ChainContextSubstFormat2;
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struct TTO_ChainContextSubstFormat3_
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{
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FT_UShort BacktrackGlyphCount;
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/* number of backtrack glyphs */
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TTO_Coverage* BacktrackCoverage;
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/* array of backtrack Coverage
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tables */
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FT_UShort InputGlyphCount;
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/* number of input glyphs */
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TTO_Coverage* InputCoverage;
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/* array of input coverage
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tables */
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FT_UShort LookaheadGlyphCount;
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/* number of lookahead glyphs */
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TTO_Coverage* LookaheadCoverage;
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/* array of lookahead coverage
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tables */
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FT_UShort SubstCount; /* number of SubstLookupRecords */
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TTO_SubstLookupRecord* SubstLookupRecord;
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/* array of substitution lookups */
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};
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typedef struct TTO_ChainContextSubstFormat3_ TTO_ChainContextSubstFormat3;
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struct TTO_ChainContextSubst_
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{
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FT_UShort SubstFormat; /* 1, 2, or 3 */
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union
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{
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TTO_ChainContextSubstFormat1 ccsf1;
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TTO_ChainContextSubstFormat2 ccsf2;
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TTO_ChainContextSubstFormat3 ccsf3;
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} ccsf;
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};
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typedef struct TTO_ChainContextSubst_ TTO_ChainContextSubst;
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union TTO_GSUB_SubTable_
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{
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TTO_SingleSubst single;
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TTO_MultipleSubst multiple;
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TTO_AlternateSubst alternate;
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TTO_LigatureSubst ligature;
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TTO_ContextSubst context;
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TTO_ChainContextSubst chain;
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};
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typedef union TTO_GSUB_SubTable_ TTO_GSUB_SubTable;
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/* A simple string object. It can both `send' and `receive' data.
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In case of sending, `length' and `pos' will be used. In case of
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receiving, `pos' points to the first free slot, and `allocated'
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specifies the amount of allocated memory (and the `length' field
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will be ignored). The routine TT_Add_String() will increase the
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amount of memory if necessary. After end of receive, `length'
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should be set to the value of `pos', and `pos' will be set to zero.
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`properties' (which is treated as a bit field) gives the glyph's
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properties: If a certain bit is set for a glyph, the feature which
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has the same bit set in its property value is applied.
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`components' is an internal array which tracks components of
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ligatures. We need this for MarkToLigature Attachment Positioning
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Subtables (in GPOS) together with `ligIDs' (which is used to mark
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ligatures and the skipped glyphs during a ligature lookup).
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`max_ligID' is increased after a successful ligature lookup.
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NEVER modify any elements of the structure! You should rather copy
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its contents if necessary.
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TT_Add_String() will also handle allocation; you should use
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free() in case you want to destroy the arrays in the object. */
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/* finally, the GSUB API */
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/* EXPORT_DEF
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TT_Error TT_Init_GSUB_Extension( TT_Engine engine ); */
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EXPORT_DEF
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FT_Error TT_Load_GSUB_Table( FT_Face face,
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TTO_GSUBHeader** gsub,
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TTO_GDEFHeader* gdef );
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EXPORT_DEF
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FT_Error TT_Done_GSUB_Table( TTO_GSUBHeader* gsub );
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EXPORT_DEF
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FT_Error TT_GSUB_Select_Script( TTO_GSUBHeader* gsub,
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FT_ULong script_tag,
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FT_UShort* script_index );
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EXPORT_DEF
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FT_Error TT_GSUB_Select_Language( TTO_GSUBHeader* gsub,
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FT_ULong language_tag,
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FT_UShort script_index,
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FT_UShort* language_index,
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FT_UShort* req_feature_index );
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EXPORT_DEF
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FT_Error TT_GSUB_Select_Feature( TTO_GSUBHeader* gsub,
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FT_ULong feature_tag,
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FT_UShort script_index,
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FT_UShort language_index,
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FT_UShort* feature_index );
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EXPORT_DEF
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FT_Error TT_GSUB_Query_Scripts( TTO_GSUBHeader* gsub,
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FT_ULong** script_tag_list );
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EXPORT_DEF
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FT_Error TT_GSUB_Query_Languages( TTO_GSUBHeader* gsub,
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FT_UShort script_index,
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FT_ULong** language_tag_list );
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EXPORT_DEF
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FT_Error TT_GSUB_Query_Features( TTO_GSUBHeader* gsub,
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FT_UShort script_index,
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FT_UShort language_index,
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FT_ULong** feature_tag_list );
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EXPORT_DEF
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FT_Error TT_GSUB_Add_Feature( TTO_GSUBHeader* gsub,
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FT_UShort feature_index,
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FT_UInt property );
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EXPORT_DEF
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FT_Error TT_GSUB_Clear_Features( TTO_GSUBHeader* gsub );
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EXPORT_DEF
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FT_Error TT_GSUB_Register_Alternate_Function( TTO_GSUBHeader* gsub,
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TTO_AltFunction altfunc,
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void* data );
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EXPORT_DEF
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FT_Error TT_GSUB_Apply_String( TTO_GSUBHeader* gsub,
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OTL_Buffer buffer );
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#ifdef __cplusplus
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}
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#endif
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#endif /* FTXGSUB_H */
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/* END */
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