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/*******************************************************************
*
* Copyright 1996-2000 by
* David Turner, Robert Wilhelm, and Werner Lemberg.
*
* Copyright 2006 Behdad Esfahbod
*
* This is part of HarfBuzz, an OpenType Layout engine library.
*
* See the file name COPYING for licensing information.
*
******************************************************************/
#ifndef HARFBUZZ_GSUB_H
#define HARFBUZZ_GSUB_H
#include "harfbuzz-gdef.h"
#include "harfbuzz-buffer.h"
HB_BEGIN_HEADER
/* Lookup types for glyph substitution */
#define HB_GSUB_LOOKUP_SINGLE 1
#define HB_GSUB_LOOKUP_MULTIPLE 2
#define HB_GSUB_LOOKUP_ALTERNATE 3
#define HB_GSUB_LOOKUP_LIGATURE 4
#define HB_GSUB_LOOKUP_CONTEXT 5
#define HB_GSUB_LOOKUP_CHAIN 6
#define HB_GSUB_LOOKUP_EXTENSION 7
#define HB_GSUB_LOOKUP_REVERSE_CHAIN 8
/* 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
HB_GSUB_Register_Alternate_Function(). The function must return an
index into the `alternates' array. */
typedef HB_UShort (*HB_AltFunction)(HB_UInt pos,
HB_UShort glyphID,
HB_UShort num_alternates,
HB_UShort* alternates,
void* data );
struct HB_GSUBHeader_
{
HB_UInt offset;
FT_Fixed Version;
HB_ScriptList ScriptList;
HB_FeatureList FeatureList;
HB_LookupList LookupList;
HB_GDEFHeader* gdef;
/* the next two fields are used for an alternate substitution callback
function to select the proper alternate glyph. */
HB_AltFunction altfunc;
void* data;
};
typedef struct HB_GSUBHeader_ HB_GSUBHeader;
typedef HB_GSUBHeader* HB_GSUB;
HB_Error HB_Load_GSUB_Table( FT_Face face,
HB_GSUBHeader** gsub,
HB_GDEFHeader* gdef );
HB_Error HB_Done_GSUB_Table( HB_GSUBHeader* gsub );
HB_Error HB_GSUB_Select_Script( HB_GSUBHeader* gsub,
HB_UInt script_tag,
HB_UShort* script_index );
HB_Error HB_GSUB_Select_Language( HB_GSUBHeader* gsub,
HB_UInt language_tag,
HB_UShort script_index,
HB_UShort* language_index,
HB_UShort* req_feature_index );
HB_Error HB_GSUB_Select_Feature( HB_GSUBHeader* gsub,
HB_UInt feature_tag,
HB_UShort script_index,
HB_UShort language_index,
HB_UShort* feature_index );
HB_Error HB_GSUB_Query_Scripts( HB_GSUBHeader* gsub,
HB_UInt** script_tag_list );
HB_Error HB_GSUB_Query_Languages( HB_GSUBHeader* gsub,
HB_UShort script_index,
HB_UInt** language_tag_list );
HB_Error HB_GSUB_Query_Features( HB_GSUBHeader* gsub,
HB_UShort script_index,
HB_UShort language_index,
HB_UInt** feature_tag_list );
HB_Error HB_GSUB_Add_Feature( HB_GSUBHeader* gsub,
HB_UShort feature_index,
HB_UInt property );
HB_Error HB_GSUB_Clear_Features( HB_GSUBHeader* gsub );
HB_Error HB_GSUB_Register_Alternate_Function( HB_GSUBHeader* gsub,
HB_AltFunction altfunc,
void* data );
HB_Error HB_GSUB_Apply_String( HB_GSUBHeader* gsub,
HB_Buffer buffer );
HB_END_HEADER
#endif /* HARFBUZZ_GSUB_H */
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