1 /*
2  * Copyright (C) 1998-2004  David Turner and Werner Lemberg
3  * Copyright (C) 2006  Behdad Esfahbod
4  *
5  * This is part of HarfBuzz, an OpenType Layout engine library.
6  *
7  * Permission is hereby granted, without written agreement and without
8  * license or royalty fees, to use, copy, modify, and distribute this
9  * software and its documentation for any purpose, provided that the
10  * above copyright notice and the following two paragraphs appear in
11  * all copies of this software.
12  *
13  * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
14  * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
15  * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
16  * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
17  * DAMAGE.
18  *
19  * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
20  * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
21  * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
22  * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
23  * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
24  */
25 
26 #ifndef HARFBUZZ_GSUB_H
27 #define HARFBUZZ_GSUB_H
28 
29 #include "harfbuzz-gdef.h"
30 #include "harfbuzz-buffer.h"
31 
32 HB_BEGIN_HEADER
33 
34 
35 /* Lookup types for glyph substitution */
36 
37 #define HB_GSUB_LOOKUP_SINGLE        1
38 #define HB_GSUB_LOOKUP_MULTIPLE      2
39 #define HB_GSUB_LOOKUP_ALTERNATE     3
40 #define HB_GSUB_LOOKUP_LIGATURE      4
41 #define HB_GSUB_LOOKUP_CONTEXT       5
42 #define HB_GSUB_LOOKUP_CHAIN         6
43 #define HB_GSUB_LOOKUP_EXTENSION     7
44 #define HB_GSUB_LOOKUP_REVERSE_CHAIN 8
45 
46 
47 /* A pointer to a function which selects the alternate glyph.  `pos' is
48    the position of the glyph with index `glyphID', `num_alternates'
49    gives the number of alternates in the `alternates' array.  `data'
50    points to the user-defined structure specified during a call to
51    HB_GSUB_Register_Alternate_Function().  The function must return an
52    index into the `alternates' array.                                   */
53 
54 typedef HB_UShort  (*HB_AltFunction)(HB_UInt    pos,
55 				      HB_UShort   glyphID,
56 				      HB_UShort   num_alternates,
57 				      HB_UShort*  alternates,
58 				      void*       data );
59 
60 
61 struct  HB_GSUBHeader_
62 {
63   HB_UInt         offset;
64 
65   HB_16Dot16         Version;
66 
67   HB_ScriptList   ScriptList;
68   HB_FeatureList  FeatureList;
69   HB_LookupList   LookupList;
70 
71   HB_GDEFHeader*  gdef;
72 
73   /* the next two fields are used for an alternate substitution callback
74      function to select the proper alternate glyph.                      */
75 
76   HB_AltFunction  altfunc;
77   void*            data;
78 };
79 
80 typedef struct HB_GSUBHeader_   HB_GSUBHeader;
81 typedef HB_GSUBHeader*  HB_GSUB;
82 
83 
84 HB_Error  HB_Load_GSUB_Table( HB_Stream       stream,
85 			      HB_GSUBHeader** gsub,
86 			      HB_GDEFHeader*  gdef,
87                               HB_Stream       gdefStream );
88 
89 
90 HB_Error  HB_Done_GSUB_Table( HB_GSUBHeader*  gsub );
91 
92 
93 HB_Error  HB_GSUB_Select_Script( HB_GSUBHeader*  gsub,
94 				 HB_UInt         script_tag,
95 				 HB_UShort*       script_index );
96 
97 HB_Error  HB_GSUB_Select_Language( HB_GSUBHeader*  gsub,
98 				   HB_UInt         language_tag,
99 				   HB_UShort        script_index,
100 				   HB_UShort*       language_index,
101 				   HB_UShort*       req_feature_index );
102 
103 HB_Error  HB_GSUB_Select_Feature( HB_GSUBHeader*  gsub,
104 				  HB_UInt         feature_tag,
105 				  HB_UShort        script_index,
106 				  HB_UShort        language_index,
107 				  HB_UShort*       feature_index );
108 
109 
110 HB_Error  HB_GSUB_Query_Scripts( HB_GSUBHeader*  gsub,
111 				 HB_UInt**       script_tag_list );
112 
113 HB_Error  HB_GSUB_Query_Languages( HB_GSUBHeader*  gsub,
114 				   HB_UShort        script_index,
115 				   HB_UInt**       language_tag_list );
116 
117 HB_Error  HB_GSUB_Query_Features( HB_GSUBHeader*  gsub,
118 				  HB_UShort        script_index,
119 				  HB_UShort        language_index,
120 				  HB_UInt**       feature_tag_list );
121 
122 
123 HB_Error  HB_GSUB_Add_Feature( HB_GSUBHeader*  gsub,
124 			       HB_UShort        feature_index,
125 			       HB_UInt          property );
126 
127 HB_Error  HB_GSUB_Clear_Features( HB_GSUBHeader*  gsub );
128 
129 
130 HB_Error  HB_GSUB_Register_Alternate_Function( HB_GSUBHeader*  gsub,
131 					       HB_AltFunction  altfunc,
132 					       void*            data );
133 
134 
135 HB_Error  HB_GSUB_Apply_String( HB_GSUBHeader*   gsub,
136 				HB_Buffer        buffer );
137 
138 
139 HB_END_HEADER
140 
141 #endif /* HARFBUZZ_GSUB_H */
142