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1 /***************************************************************************/
2 /* */
3 /* ttdriver.c */
4 /* */
5 /* TrueType font driver implementation (body). */
6 /* */
7 /* Copyright 1996-2000 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 #include <freetype/internal/ftdebug.h>
20 #include <freetype/internal/ftstream.h>
21 #include <freetype/internal/sfnt.h>
22 #include <freetype/ttnameid.h>
23
24
25 #ifdef FT_FLAT_COMPILE
26
27 #include "ttdriver.h"
28 #include "ttgload.h"
29
30 #else
31
32 #include <truetype/ttdriver.h>
33 #include <truetype/ttgload.h>
34
35 #endif
36
37
38 /*************************************************************************/
39 /* */
40 /* The macro FT_COMPONENT is used in trace mode. It is an implicit */
41 /* parameter of the FT_TRACE() and FT_ERROR() macros, used to print/log */
42 /* messages during execution. */
43 /* */
44 #undef FT_COMPONENT
45 #define FT_COMPONENT trace_ttdriver
46
47
48 /*************************************************************************/
49 /*************************************************************************/
50 /*************************************************************************/
51 /**** ****/
52 /**** ****/
53 /**** F A C E S ****/
54 /**** ****/
55 /**** ****/
56 /*************************************************************************/
57 /*************************************************************************/
58 /*************************************************************************/
59
60
61 #undef PAIR_TAG
62 #define PAIR_TAG( left, right ) ( ( (FT_ULong)left << 16 ) | \
63 (FT_ULong)right )
64
65
66 /*************************************************************************/
67 /* */
68 /* <Function> */
69 /* Get_Kerning */
70 /* */
71 /* <Description> */
72 /* A driver method used to return the kerning vector between two */
73 /* glyphs of the same face. */
74 /* */
75 /* <Input> */
76 /* face :: A handle to the source face object. */
77 /* */
78 /* left_glyph :: The index of the left glyph in the kern pair. */
79 /* */
80 /* right_glyph :: The index of the right glyph in the kern pair. */
81 /* */
82 /* <Output> */
83 /* kerning :: The kerning vector. This is in font units for */
84 /* scalable formats, and in pixels for fixed-sizes */
85 /* formats. */
86 /* */
87 /* <Return> */
88 /* FreeType error code. 0 means success. */
89 /* */
90 /* <Note> */
91 /* Only horizontal layouts (left-to-right & right-to-left) are */
92 /* supported by this function. Other layouts, or more sophisticated */
93 /* kernings, are out of scope of this method (the basic driver */
94 /* interface is meant to be simple). */
95 /* */
96 /* They can be implemented by format-specific interfaces. */
97 /* */
98 static
99 FT_Error Get_Kerning( TT_Face face,
100 FT_UInt left_glyph,
101 FT_UInt right_glyph,
102 FT_Vector* kerning )
103 {
104 TT_Kern_0_Pair* pair;
105
106
107 if ( !face )
108 return TT_Err_Invalid_Face_Handle;
109
110 kerning->x = 0;
111 kerning->y = 0;
112
113 if ( face->kern_pairs )
114 {
115 /* there are some kerning pairs in this font file! */
116 FT_ULong search_tag = PAIR_TAG( left_glyph, right_glyph );
117 FT_Long left, right;
118
119
120 left = 0;
121 right = face->num_kern_pairs - 1;
122
123 while ( left <= right )
124 {
125 FT_Int middle = left + ( ( right - left ) >> 1 );
126 FT_ULong cur_pair;
127
128
129 pair = face->kern_pairs + middle;
130 cur_pair = PAIR_TAG( pair->left, pair->right );
131
132 if ( cur_pair == search_tag )
133 goto Found;
134
135 if ( cur_pair < search_tag )
136 left = middle + 1;
137 else
138 right = middle - 1;
139 }
140 }
141
142 Exit:
143 return TT_Err_Ok;
144
145 Found:
146 kerning->x = pair->value;
147 goto Exit;
148 }
149
150
151 #undef PAIR_TAG
152
153
154 /*************************************************************************/
155 /*************************************************************************/
156 /*************************************************************************/
157 /**** ****/
158 /**** ****/
159 /**** S I Z E S ****/
160 /**** ****/
161 /**** ****/
162 /*************************************************************************/
163 /*************************************************************************/
164 /*************************************************************************/
165
166
167 /*************************************************************************/
168 /* */
169 /* <Function> */
170 /* Set_Char_Sizes */
171 /* */
172 /* <Description> */
173 /* A driver method used to reset a size's character sizes (horizontal */
174 /* and vertical) expressed in fractional points. */
175 /* */
176 /* <Input> */
177 /* char_width :: The character width expressed in 26.6 */
178 /* fractional points. */
179 /* */
180 /* char_height :: The character height expressed in 26.6 */
181 /* fractional points. */
182 /* */
183 /* horz_resolution :: The horizontal resolution of the output device. */
184 /* */
185 /* vert_resolution :: The vertical resolution of the output device. */
186 /* */
187 /* <InOut> */
188 /* size :: A handle to the target size object. */
189 /* */
190 /* <Return> */
191 /* FreeType error code. 0 means success. */
192 /* */
193 static
194 FT_Error Set_Char_Sizes( TT_Size size,
195 FT_F26Dot6 char_width,
196 FT_F26Dot6 char_height,
197 FT_UInt horz_resolution,
198 FT_UInt vert_resolution )
199 {
200 FT_Size_Metrics* metrics = &size->root.metrics;
201 TT_Face face = (TT_Face)size->root.face;
202 FT_Long dim_x, dim_y;
203
204
205 /* This bit flag, when set, indicates that the pixel size must be */
206 /* truncated to an integer. Nearly all TrueType fonts have this */
207 /* bit set, as hinting won't work really well otherwise. */
208 /* */
209 /* However, for those rare fonts who do not set it, we override */
210 /* the default computations performed by the base layer. I */
211 /* really don't know whether this is useful, but hey, that's the */
212 /* spec :-) */
213 /* */
214 if ( ( face->header.Flags & 8 ) == 0 )
215 {
216 /* Compute pixel sizes in 26.6 units */
217 dim_x = ( char_width * horz_resolution ) / 72;
218 dim_y = ( char_height * vert_resolution ) / 72;
219
220 metrics->x_scale = FT_DivFix( dim_x, face->root.units_per_EM );
221 metrics->y_scale = FT_DivFix( dim_y, face->root.units_per_EM );
222
223 metrics->x_ppem = (FT_UShort)( dim_x >> 6 );
224 metrics->y_ppem = (FT_UShort)( dim_y >> 6 );
225 }
226
227 size->ttmetrics.valid = FALSE;
228
229 return TT_Reset_Size( size );
230 }
231
232
233 /*************************************************************************/
234 /* */
235 /* <Function> */
236 /* Set_Pixel_Sizes */
237 /* */
238 /* <Description> */
239 /* A driver method used to reset a size's character sizes (horizontal */
240 /* and vertical) expressed in integer pixels. */
241 /* */
242 /* <Input> */
243 /* pixel_width :: The character width expressed in integer pixels. */
244 /* */
245 /* pixel_height :: The character height expressed in integer pixels. */
246 /* */
247 /* <InOut> */
248 /* size :: A handle to the target size object. */
249 /* */
250 /* <Return> */
251 /* FreeType error code. 0 means success. */
252 /* */
253 static
254 FT_Error Set_Pixel_Sizes( TT_Size size,
255 FT_UInt pixel_width,
256 FT_UInt pixel_height )
257 {
258 FT_UNUSED( pixel_width );
259 FT_UNUSED( pixel_height );
260
261 /* many things have been pre-computed by the base layer */
262
263 size->ttmetrics.valid = FALSE;
264
265 return TT_Reset_Size( size );
266 }
267
268
269 /*************************************************************************/
270 /* */
271 /* <Function> */
272 /* Load_Glyph */
273 /* */
274 /* <Description> */
275 /* A driver method used to load a glyph within a given glyph slot. */
276 /* */
277 /* <Input> */
278 /* slot :: A handle to the target slot object where the glyph */
279 /* will be loaded. */
280 /* */
281 /* size :: A handle to the source face size at which the glyph */
282 /* must be scaled, loaded, etc. */
283 /* */
284 /* glyph_index :: The index of the glyph in the font file. */
285 /* */
286 /* load_flags :: A flag indicating what to load for this glyph. The */
287 /* FTLOAD_??? constants can be used to control the */
288 /* glyph loading process (e.g., whether the outline */
289 /* should be scaled, whether to load bitmaps or not, */
290 /* whether to hint the outline, etc). */
291 /* */
292 /* <Return> */
293 /* FreeType error code. 0 means success. */
294 /* */
295 static
296 FT_Error Load_Glyph( TT_GlyphSlot slot,
297 TT_Size size,
298 FT_UShort glyph_index,
299 FT_UInt load_flags )
300 {
301 FT_Error error;
302
303
304 if ( !slot )
305 return TT_Err_Invalid_Glyph_Handle;
306
307 /* check whether we want a scaled outline or bitmap */
308 if ( !size )
309 load_flags |= FT_LOAD_NO_SCALE | FT_LOAD_NO_HINTING;
310
311 if ( load_flags & FT_LOAD_NO_SCALE )
312 size = NULL;
313
314 /* reset the size object if necessary */
315 if ( size )
316 {
317 /* these two object must have the same parent */
318 if ( size->root.face != slot->face )
319 return TT_Err_Invalid_Face_Handle;
320
321 if ( !size->ttmetrics.valid )
322 {
323 if ( FT_SET_ERROR( TT_Reset_Size( size ) ) )
324 return error;
325 }
326 }
327
328 /* now load the glyph outline if necessary */
329 error = TT_Load_Glyph( size, slot, glyph_index, load_flags );
330
331 /* force drop-out mode to 2 - irrelevant now */
332 /* slot->outline.dropout_mode = 2; */
333
334 return error;
335 }
336
337
338 /*************************************************************************/
339 /*************************************************************************/
340 /*************************************************************************/
341 /**** ****/
342 /**** ****/
343 /**** C H A R A C T E R M A P P I N G S ****/
344 /**** ****/
345 /**** ****/
346 /*************************************************************************/
347 /*************************************************************************/
348 /*************************************************************************/
349
350 /*************************************************************************/
351 /* */
352 /* <Function> */
353 /* Get_Char_Index */
354 /* */
355 /* <Description> */
356 /* Uses a charmap to return a given character code's glyph index. */
357 /* */
358 /* <Input> */
359 /* charmap :: A handle to the source charmap object. */
360 /* charcode :: The character code. */
361 /* */
362 /* <Return> */
363 /* Glyph index. 0 means `undefined character code'. */
364 /* */
365 static
366 FT_UInt Get_Char_Index( TT_CharMap charmap,
367 FT_Long charcode )
368 {
369 FT_Error error;
370 TT_Face face;
371 TT_CMapTable* cmap;
372
373
374 cmap = &charmap->cmap;
375 face = (TT_Face)charmap->root.face;
376
377 /* Load table if needed */
378 if ( !cmap->loaded )
379 {
380 SFNT_Interface* sfnt = (SFNT_Interface*)face->sfnt;
381
382
383 error = sfnt->load_charmap( face, cmap, face->root.stream );
384 if ( error )
385 return 0;
386
387 cmap->loaded = TRUE;
388 }
389
390 if ( cmap->get_index )
391 return cmap->get_index( cmap, charcode );
392 else
393 return 0;
394 }
395
396
397 /*************************************************************************/
398 /*************************************************************************/
399 /*************************************************************************/
400 /**** ****/
401 /**** ****/
402 /**** D R I V E R I N T E R F A C E ****/
403 /**** ****/
404 /**** ****/
405 /*************************************************************************/
406 /*************************************************************************/
407 /*************************************************************************/
408
409
410 static
411 FT_Module_Interface tt_get_interface( TT_Driver driver,
412 const char* interface )
413 {
414 FT_Module sfntd = FT_Get_Module( driver->root.root.library,
415 "sfnt" );
416 SFNT_Interface* sfnt;
417
418
419 /* only return the default interface from the SFNT module */
420 if ( sfntd )
421 {
422 sfnt = (SFNT_Interface*)( sfntd->clazz->module_interface );
423 if ( sfnt )
424 return sfnt->get_interface( FT_MODULE( driver ), interface );
425 }
426
427 return 0;
428 }
429
430
431 /* The FT_DriverInterface structure is defined in ftdriver.h. */
432
433 const FT_Driver_Class tt_driver_class =
434 {
435 {
436 ft_module_font_driver |
437 ft_module_driver_scalable |
438 #ifdef TT_CONFIG_OPTION_BYTECODE_INTERPRETER
439 ft_module_driver_has_hinter,
440 #else
441 0,
442 #endif
443
444 sizeof ( TT_DriverRec ),
445
446 "truetype", /* driver name */
447 0x10000L, /* driver version == 1.0 */
448 0x20000L, /* driver requires FreeType 2.0 or above */
449
450 (void*)0, /* driver specific interface */
451
452 (FT_Module_Constructor)TT_Init_Driver,
453 (FT_Module_Destructor) TT_Done_Driver,
454 (FT_Module_Requester) tt_get_interface,
455 },
456
457 sizeof ( TT_FaceRec ),
458 sizeof ( TT_SizeRec ),
459 sizeof ( FT_GlyphSlotRec ),
460
461
462 (FTDriver_initFace) TT_Init_Face,
463 (FTDriver_doneFace) TT_Done_Face,
464 (FTDriver_initSize) TT_Init_Size,
465 (FTDriver_doneSize) TT_Done_Size,
466 (FTDriver_initGlyphSlot)0,
467 (FTDriver_doneGlyphSlot)0,
468
469 (FTDriver_setCharSizes) Set_Char_Sizes,
470 (FTDriver_setPixelSizes)Set_Pixel_Sizes,
471 (FTDriver_loadGlyph) Load_Glyph,
472 (FTDriver_getCharIndex) Get_Char_Index,
473
474 (FTDriver_getKerning) Get_Kerning,
475 (FTDriver_attachFile) 0,
476 (FTDriver_getAdvances) 0
477 };
478
479
480 #ifdef FT_CONFIG_OPTION_DYNAMIC_DRIVERS
481
482
483 /*************************************************************************/
484 /* */
485 /* <Function> */
486 /* getDriverInterface */
487 /* */
488 /* <Description> */
489 /* This function is used when compiling the TrueType driver as a */
490 /* shared library (`.DLL' or `.so'). It will be used by the */
491 /* high-level library of FreeType to retrieve the address of the */
492 /* driver's generic interface. */
493 /* */
494 /* It shouldn't be implemented in a static build, as each driver must */
495 /* have the same function as an exported entry point. */
496 /* */
497 /* <Return> */
498 /* The address of the TrueType's driver generic interface. The */
499 /* format-specific interface can then be retrieved through the method */
500 /* interface->get_format_interface. */
501 /* */
502 EXPORT_FUNC( const FT_Driver_Class* ) getDriverClass( void )
503 {
504 return &tt_driver_class;
505 }
506
507
508 #endif /* CONFIG_OPTION_DYNAMIC_DRIVERS */
509
510
511 /* END */
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