1 /***************************************************************************/
2 /* */
3 /* ftdrv.h */
4 /* */
5 /* FreeType internal font driver interface (specification). */
6 /* */
7 /* Copyright 1996-2018 by */
8 /* David Turner, Robert Wilhelm, and Werner Lemberg. */
9 /* */
10 /* This file is part of the FreeType project, and may only be used, */
11 /* modified, and distributed under the terms of the FreeType project */
12 /* license, LICENSE.TXT. By continuing to use, modify, or distribute */
13 /* this file you indicate that you have read the license and */
14 /* understand and accept it fully. */
15 /* */
16 /***************************************************************************/
17
18
19 #ifndef FTDRV_H_
20 #define FTDRV_H_
21
22
23 #include <ft2build.h>
24 #include FT_MODULE_H
25
26
27 FT_BEGIN_HEADER
28
29
30 typedef FT_Error
31 (*FT_Face_InitFunc)( FT_Stream stream,
32 FT_Face face,
33 FT_Int typeface_index,
34 FT_Int num_params,
35 FT_Parameter* parameters );
36
37 typedef void
38 (*FT_Face_DoneFunc)( FT_Face face );
39
40
41 typedef FT_Error
42 (*FT_Size_InitFunc)( FT_Size size );
43
44 typedef void
45 (*FT_Size_DoneFunc)( FT_Size size );
46
47
48 typedef FT_Error
49 (*FT_Slot_InitFunc)( FT_GlyphSlot slot );
50
51 typedef void
52 (*FT_Slot_DoneFunc)( FT_GlyphSlot slot );
53
54
55 typedef FT_Error
56 (*FT_Size_RequestFunc)( FT_Size size,
57 FT_Size_Request req );
58
59 typedef FT_Error
60 (*FT_Size_SelectFunc)( FT_Size size,
61 FT_ULong size_index );
62
63 typedef FT_Error
64 (*FT_Slot_LoadFunc)( FT_GlyphSlot slot,
65 FT_Size size,
66 FT_UInt glyph_index,
67 FT_Int32 load_flags );
68
69
70 typedef FT_Error
71 (*FT_Face_GetKerningFunc)( FT_Face face,
72 FT_UInt left_glyph,
73 FT_UInt right_glyph,
74 FT_Vector* kerning );
75
76
77 typedef FT_Error
78 (*FT_Face_AttachFunc)( FT_Face face,
79 FT_Stream stream );
80
81
82 typedef FT_Error
83 (*FT_Face_GetAdvancesFunc)( FT_Face face,
84 FT_UInt first,
85 FT_UInt count,
86 FT_Int32 flags,
87 FT_Fixed* advances );
88
89
90 /*************************************************************************/
91 /* */
92 /* <Struct> */
93 /* FT_Driver_ClassRec */
94 /* */
95 /* <Description> */
96 /* The font driver class. This structure mostly contains pointers to */
97 /* driver methods. */
98 /* */
99 /* <Fields> */
100 /* root :: The parent module. */
101 /* */
102 /* face_object_size :: The size of a face object in bytes. */
103 /* */
104 /* size_object_size :: The size of a size object in bytes. */
105 /* */
106 /* slot_object_size :: The size of a glyph object in bytes. */
107 /* */
108 /* init_face :: The format-specific face constructor. */
109 /* */
110 /* done_face :: The format-specific face destructor. */
111 /* */
112 /* init_size :: The format-specific size constructor. */
113 /* */
114 /* done_size :: The format-specific size destructor. */
115 /* */
116 /* init_slot :: The format-specific slot constructor. */
117 /* */
118 /* done_slot :: The format-specific slot destructor. */
119 /* */
120 /* */
121 /* load_glyph :: A function handle to load a glyph to a slot. */
122 /* This field is mandatory! */
123 /* */
124 /* get_kerning :: A function handle to return the unscaled */
125 /* kerning for a given pair of glyphs. Can be */
126 /* set to 0 if the format doesn't support */
127 /* kerning. */
128 /* */
129 /* attach_file :: This function handle is used to read */
130 /* additional data for a face from another */
131 /* file/stream. For example, this can be used to */
132 /* add data from AFM or PFM files on a Type 1 */
133 /* face, or a CIDMap on a CID-keyed face. */
134 /* */
135 /* get_advances :: A function handle used to return advance */
136 /* widths of `count' glyphs (in font units), */
137 /* starting at `first'. The `vertical' flag must */
138 /* be set to get vertical advance heights. The */
139 /* `advances' buffer is caller-allocated. */
140 /* The idea of this function is to be able to */
141 /* perform device-independent text layout without */
142 /* loading a single glyph image. */
143 /* */
144 /* request_size :: A handle to a function used to request the new */
145 /* character size. Can be set to 0 if the */
146 /* scaling done in the base layer suffices. */
147 /* */
148 /* select_size :: A handle to a function used to select a new */
149 /* fixed size. It is used only if */
150 /* @FT_FACE_FLAG_FIXED_SIZES is set. Can be set */
151 /* to 0 if the scaling done in the base layer */
152 /* suffices. */
153 /* <Note> */
154 /* Most function pointers, with the exception of `load_glyph', can be */
155 /* set to 0 to indicate a default behaviour. */
156 /* */
157 typedef struct FT_Driver_ClassRec_
158 {
159 FT_Module_Class root;
160
161 FT_Long face_object_size;
162 FT_Long size_object_size;
163 FT_Long slot_object_size;
164
165 FT_Face_InitFunc init_face;
166 FT_Face_DoneFunc done_face;
167
168 FT_Size_InitFunc init_size;
169 FT_Size_DoneFunc done_size;
170
171 FT_Slot_InitFunc init_slot;
172 FT_Slot_DoneFunc done_slot;
173
174 FT_Slot_LoadFunc load_glyph;
175
176 FT_Face_GetKerningFunc get_kerning;
177 FT_Face_AttachFunc attach_file;
178 FT_Face_GetAdvancesFunc get_advances;
179
180 /* since version 2.2 */
181 FT_Size_RequestFunc request_size;
182 FT_Size_SelectFunc select_size;
183
184 } FT_Driver_ClassRec, *FT_Driver_Class;
185
186
187 /*************************************************************************/
188 /* */
189 /* <Macro> */
190 /* FT_DECLARE_DRIVER */
191 /* */
192 /* <Description> */
193 /* Used to create a forward declaration of an FT_Driver_ClassRec */
194 /* struct instance. */
195 /* */
196 /* <Macro> */
197 /* FT_DEFINE_DRIVER */
198 /* */
199 /* <Description> */
200 /* Used to initialize an instance of FT_Driver_ClassRec struct. */
201 /* */
202 /* When FT_CONFIG_OPTION_PIC is defined a `create' function has to be */
203 /* called with a pointer where the allocated structure is returned. */
204 /* And when it is no longer needed a `destroy' function needs to be */
205 /* called to release that allocation. */
206 /* */
207 /* `ftinit.c' (ft_create_default_module_classes) already contains a */
208 /* mechanism to call these functions for the default modules */
209 /* described in `ftmodule.h'. */
210 /* */
211 /* Notice that the created `create' and `destroy' functions call */
212 /* `pic_init' and `pic_free' to allow you to manually allocate and */
213 /* initialize any additional global data, like a module specific */
214 /* interface, and put them in the global pic container defined in */
215 /* `ftpic.h'. If you don't need them just implement the functions as */
216 /* empty to resolve the link error. Also the `pic_init' and */
217 /* `pic_free' functions should be declared in `pic.h', to be referred */
218 /* by driver definition calling `FT_DEFINE_DRIVER' in following. */
219 /* */
220 /* When FT_CONFIG_OPTION_PIC is not defined the struct will be */
221 /* allocated in the global scope (or the scope where the macro is */
222 /* used). */
223 /* */
224 #ifndef FT_CONFIG_OPTION_PIC
225
226 #define FT_DECLARE_DRIVER( class_ ) \
227 FT_CALLBACK_TABLE \
228 const FT_Driver_ClassRec class_;
229
230 #define FT_DEFINE_DRIVER( \
231 class_, \
232 flags_, \
233 size_, \
234 name_, \
235 version_, \
236 requires_, \
237 interface_, \
238 init_, \
239 done_, \
240 get_interface_, \
241 face_object_size_, \
242 size_object_size_, \
243 slot_object_size_, \
244 init_face_, \
245 done_face_, \
246 init_size_, \
247 done_size_, \
248 init_slot_, \
249 done_slot_, \
250 load_glyph_, \
251 get_kerning_, \
252 attach_file_, \
253 get_advances_, \
254 request_size_, \
255 select_size_ ) \
256 FT_CALLBACK_TABLE_DEF \
257 const FT_Driver_ClassRec class_ = \
258 { \
259 FT_DEFINE_ROOT_MODULE( flags_, \
260 size_, \
261 name_, \
262 version_, \
263 requires_, \
264 interface_, \
265 init_, \
266 done_, \
267 get_interface_ ) \
268 \
269 face_object_size_, \
270 size_object_size_, \
271 slot_object_size_, \
272 \
273 init_face_, \
274 done_face_, \
275 \
276 init_size_, \
277 done_size_, \
278 \
279 init_slot_, \
280 done_slot_, \
281 \
282 load_glyph_, \
283 \
284 get_kerning_, \
285 attach_file_, \
286 get_advances_, \
287 \
288 request_size_, \
289 select_size_ \
290 };
291
292 #else /* FT_CONFIG_OPTION_PIC */
293
294 #define FT_DECLARE_DRIVER( class_ ) FT_DECLARE_MODULE( class_ )
295
296 #define FT_DEFINE_DRIVER( \
297 class_, \
298 flags_, \
299 size_, \
300 name_, \
301 version_, \
302 requires_, \
303 interface_, \
304 init_, \
305 done_, \
306 get_interface_, \
307 face_object_size_, \
308 size_object_size_, \
309 slot_object_size_, \
310 init_face_, \
311 done_face_, \
312 init_size_, \
313 done_size_, \
314 init_slot_, \
315 done_slot_, \
316 load_glyph_, \
317 get_kerning_, \
318 attach_file_, \
319 get_advances_, \
320 request_size_, \
321 select_size_ ) \
322 void \
323 FT_Destroy_Class_ ## class_( FT_Library library, \
324 FT_Module_Class* clazz ) \
325 { \
326 FT_Memory memory = library->memory; \
327 FT_Driver_Class dclazz = (FT_Driver_Class)clazz; \
328 \
329 \
330 class_ ## _pic_free( library ); \
331 if ( dclazz ) \
332 FT_FREE( dclazz ); \
333 } \
334 \
335 \
336 FT_Error \
337 FT_Create_Class_ ## class_( FT_Library library, \
338 FT_Module_Class** output_class ) \
339 { \
340 FT_Driver_Class clazz = NULL; \
341 FT_Error error; \
342 FT_Memory memory = library->memory; \
343 \
344 \
345 if ( FT_ALLOC( clazz, sizeof ( *clazz ) ) ) \
346 return error; \
347 \
348 error = class_ ## _pic_init( library ); \
349 if ( error ) \
350 { \
351 FT_FREE( clazz ); \
352 return error; \
353 } \
354 \
355 FT_DEFINE_ROOT_MODULE( flags_, \
356 size_, \
357 name_, \
358 version_, \
359 requires_, \
360 interface_, \
361 init_, \
362 done_, \
363 get_interface_ ) \
364 \
365 clazz->face_object_size = face_object_size_; \
366 clazz->size_object_size = size_object_size_; \
367 clazz->slot_object_size = slot_object_size_; \
368 \
369 clazz->init_face = init_face_; \
370 clazz->done_face = done_face_; \
371 \
372 clazz->init_size = init_size_; \
373 clazz->done_size = done_size_; \
374 \
375 clazz->init_slot = init_slot_; \
376 clazz->done_slot = done_slot_; \
377 \
378 clazz->load_glyph = load_glyph_; \
379 \
380 clazz->get_kerning = get_kerning_; \
381 clazz->attach_file = attach_file_; \
382 clazz->get_advances = get_advances_; \
383 \
384 clazz->request_size = request_size_; \
385 clazz->select_size = select_size_; \
386 \
387 *output_class = (FT_Module_Class*)clazz; \
388 \
389 return FT_Err_Ok; \
390 }
391
392
393 #endif /* FT_CONFIG_OPTION_PIC */
394
395 FT_END_HEADER
396
397 #endif /* FTDRV_H_ */
398
399
400 /* END */