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/*******************************************************************
*
* 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_
{
TT_UShort GlyphCount; /* number of input glyphs */
TT_UShort SubstCount; /* number of SubstLookupRecords */
TTO_Coverage* Coverage; /* array of Coverage tables */
TTO_SubstLookupRecord* SubstLookupRecord;
/* array of substitution lookups */
};
typedef struct TTO_ContextSubstFormat3_ TTO_ContextSubstFormat3;
struct TTO_ContextSubst_
{
TT_UShort SubstFormat; /* 1, 2, or 3 */
union
{
TTO_ContextSubstFormat1 csf1;
TTO_ContextSubstFormat2 csf2;
TTO_ContextSubstFormat3 csf3;
} csf;
};
typedef struct TTO_ContextSubst_ TTO_ContextSubst;
/* LookupType 6 */
struct TTO_ChainSubRule_
{
TT_UShort BacktrackGlyphCount;
/* total number of backtrack glyphs */
TT_UShort* Backtrack; /* array of backtrack glyph IDs */
TT_UShort InputGlyphCount;
/* total number of input glyphs */
TT_UShort* Input; /* array of input glyph IDs */
TT_UShort LookaheadGlyphCount;
/* total number of lookahead glyphs */
TT_UShort* Lookahead; /* array of lookahead glyph IDs */
TT_UShort SubstCount; /* number of SubstLookupRecords */
TTO_SubstLookupRecord* SubstLookupRecord;
/* array of SubstLookupRecords */
};
typedef struct TTO_ChainSubRule_ TTO_ChainSubRule;
struct TTO_ChainSubRuleSet_
{
TT_UShort ChainSubRuleCount;
/* number of ChainSubRule tables */
TTO_ChainSubRule* ChainSubRule; /* array of ChainSubRule tables */
};
typedef struct TTO_ChainSubRuleSet_ TTO_ChainSubRuleSet;
struct TTO_ChainContextSubstFormat1_
{
TTO_Coverage Coverage; /* Coverage table */
TT_UShort ChainSubRuleSetCount;
/* number of ChainSubRuleSet tables */
TTO_ChainSubRuleSet* ChainSubRuleSet;
/* array of ChainSubRuleSet tables */
};
typedef struct TTO_ChainContextSubstFormat1_ TTO_ChainContextSubstFormat1;
struct TTO_ChainSubClassRule_
{
TT_UShort BacktrackGlyphCount;
/* total number of backtrack
classes */
TT_UShort* Backtrack; /* array of backtrack classes */
TT_UShort InputGlyphCount;
/* total number of context classes */
TT_UShort* Input; /* array of context classes */
TT_UShort LookaheadGlyphCount;
/* total number of lookahead
classes */
TT_UShort* Lookahead; /* array of lookahead classes */
TT_UShort SubstCount; /* number of SubstLookupRecords */
TTO_SubstLookupRecord* SubstLookupRecord;
/* array of substitution lookups */
};
typedef struct TTO_ChainSubClassRule_ TTO_ChainSubClassRule;
struct TTO_ChainSubClassSet_
{
TT_UShort ChainSubClassRuleCount;
/* number of ChainSubClassRule
tables */
TTO_ChainSubClassRule* ChainSubClassRule;
/* array of ChainSubClassRule
tables */
};
typedef struct TTO_ChainSubClassSet_ TTO_ChainSubClassSet;
/* The `MaxXXXLength' fields are not defined in the TTO specification
but simplifies the implementation of this format. It holds the
maximal context length used in the specific context rules. */
struct TTO_ChainContextSubstFormat2_
{
TTO_Coverage Coverage; /* Coverage table */
TT_UShort MaxBacktrackLength;
/* maximal backtrack length */
TTO_ClassDefinition BacktrackClassDef;
/* BacktrackClassDef table */
TT_UShort MaxInputLength;
/* maximal input length */
TTO_ClassDefinition InputClassDef;
/* InputClassDef table */
TT_UShort MaxLookaheadLength;
/* maximal lookahead length */
TTO_ClassDefinition LookaheadClassDef;
/* LookaheadClassDef table */
TT_UShort ChainSubClassSetCount;
/* number of ChainSubClassSet
tables */
TTO_ChainSubClassSet* ChainSubClassSet;
/* array of ChainSubClassSet
tables */
};
typedef struct TTO_ChainContextSubstFormat2_ TTO_ChainContextSubstFormat2;
struct TTO_ChainContextSubstFormat3_
{
TT_UShort BacktrackGlyphCount;
/* number of backtrack glyphs */
TTO_Coverage* BacktrackCoverage;
/* array of backtrack Coverage
tables */
TT_UShort InputGlyphCount;
/* number of input glyphs */
TTO_Coverage* InputCoverage;
/* array of input coverage
tables */
TT_UShort LookaheadGlyphCount;
/* number of lookahead glyphs */
TTO_Coverage* LookaheadCoverage;
/* array of lookahead coverage
tables */
TT_UShort SubstCount; /* number of SubstLookupRecords */
TTO_SubstLookupRecord* SubstLookupRecord;
/* array of substitution lookups */
};
typedef struct TTO_ChainContextSubstFormat3_ TTO_ChainContextSubstFormat3;
struct TTO_ChainContextSubst_
{
TT_UShort SubstFormat; /* 1, 2, or 3 */
union
{
TTO_ChainContextSubstFormat1 ccsf1;
TTO_ChainContextSubstFormat2 ccsf2;
TTO_ChainContextSubstFormat3 ccsf3;
} ccsf;
};
typedef struct TTO_ChainContextSubst_ TTO_ChainContextSubst;
union TTO_GSUB_SubTable_
{
TTO_SingleSubst single;
TTO_MultipleSubst multiple;
TTO_AlternateSubst alternate;
TTO_LigatureSubst ligature;
TTO_ContextSubst context;
TTO_ChainContextSubst chain;
};
typedef union TTO_GSUB_SubTable_ TTO_GSUB_SubTable;
/* A simple string object. It can both `send' and `receive' data.
In case of sending, `length' and `pos' will be used. In case of
receiving, `pos' points to the first free slot, and `allocated'
specifies the amount of allocated memory (and the `length' field
will be ignored). The routine TT_Add_String() will increase the
amount of memory if necessary. After end of receive, `length'
should be set to the value of `pos', and `pos' will be set to zero.
`properties' (which is treated as a bit field) gives the glyph's
properties: If a certain bit is set for a glyph, the feature which
has the same bit set in its property value is applied.
NEVER modify any elements of the structure! You should rather copy
its contents if necessary.
TT_Add_String() will also handle allocation; you should use
free() in case you want to destroy the arrays in the object. */
struct TTO_GSUB_String_
{
TT_ULong length;
TT_ULong pos;
TT_ULong allocated;
TT_UShort* string;
TT_UShort* properties;
};
typedef struct TTO_GSUB_String_ TTO_GSUB_String;
/* finally, the GSUB API */
EXPORT_DEF
TT_Error TT_Init_GSUB_Extension( TT_Engine engine );
EXPORT_DEF
TT_Error TT_Load_GSUB_Table( TT_Face face,
TTO_GSUBHeader* gsub,
TTO_GDEFHeader* gdef );
EXPORT_DEF
TT_Error TT_GSUB_Select_Script( TTO_GSUBHeader* gsub,
TT_ULong script_tag,
TT_UShort* script_index );
EXPORT_DEF
TT_Error TT_GSUB_Select_Language( TTO_GSUBHeader* gsub,
TT_ULong language_tag,
TT_UShort script_index,
TT_UShort* language_index,
TT_UShort* req_feature_index );
EXPORT_DEF
TT_Error TT_GSUB_Select_Feature( TTO_GSUBHeader* gsub,
TT_ULong feature_tag,
TT_UShort script_index,
TT_UShort language_index,
TT_UShort* feature_index );
EXPORT_DEF
TT_Error TT_GSUB_Query_Scripts( TTO_GSUBHeader* gsub,
TT_ULong** script_tag_list );
EXPORT_DEF
TT_Error TT_GSUB_Query_Languages( TTO_GSUBHeader* gsub,
TT_UShort script_index,
TT_ULong** language_tag_list );
EXPORT_DEF
TT_Error TT_GSUB_Query_Features( TTO_GSUBHeader* gsub,
TT_UShort script_index,
TT_UShort language_index,
TT_ULong** feature_tag_list );
EXPORT_DEF
TT_Error TT_GSUB_Add_Feature( TTO_GSUBHeader* gsub,
TT_UShort feature_index,
TT_UShort property );
EXPORT_DEF
TT_Error TT_GSUB_Clear_Features( TTO_GSUBHeader* gsub );
EXPORT_DEF
TT_Error TT_GSUB_Register_Alternate_Function( TTO_GSUBHeader* gsub,
TTO_AltFunction alt,
void* data );
EXPORT_DEF
TT_Error TT_GSUB_Apply_String( TTO_GSUBHeader* gsub,
TTO_GSUB_String* in,
TTO_GSUB_String* out );
EXPORT_DEF
TT_Error TT_GSUB_Add_String( TTO_GSUB_String* in,
TT_UShort num_in,
TTO_GSUB_String* out,
TT_UShort num_out,
TT_UShort* data );
#ifdef __cplusplus
}
#endif
#endif /* FTXGSUB_H */
/* END */
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