1 /***************************************************************************/
2 /* */
3 /* ttdriver.c */
4 /* */
5 /* TrueType font driver implementation (body). */
6 /* */
7 /* Copyright 1996-2001 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 /***************************************************************************/
19 #include <ft2build.h>
20 #include FT_INTERNAL_DEBUG_H
21 #include FT_INTERNAL_STREAM_H
22 #include FT_INTERNAL_SFNT_H
23 #include FT_TRUETYPE_IDS_H
25 #include "ttdriver.h"
26 #include "ttgload.h"
28 #include "tterrors.h"
31 /*************************************************************************/
32 /* */
33 /* The macro FT_COMPONENT is used in trace mode. It is an implicit */
34 /* parameter of the FT_TRACE() and FT_ERROR() macros, used to print/log */
35 /* messages during execution. */
36 /* */
37 #undef FT_COMPONENT
38 #define FT_COMPONENT trace_ttdriver
41 /*************************************************************************/
42 /*************************************************************************/
43 /*************************************************************************/
44 /**** ****/
45 /**** ****/
46 /**** F A C E S ****/
47 /**** ****/
48 /**** ****/
49 /*************************************************************************/
50 /*************************************************************************/
51 /*************************************************************************/
54 #undef PAIR_TAG
55 #define PAIR_TAG( left, right ) ( ( (FT_ULong)left << 16 ) | \
56 (FT_ULong)right )
59 /*************************************************************************/
60 /* */
61 /* <Function> */
62 /* Get_Kerning */
63 /* */
64 /* <Description> */
65 /* A driver method used to return the kerning vector between two */
66 /* glyphs of the same face. */
67 /* */
68 /* <Input> */
69 /* face :: A handle to the source face object. */
70 /* */
71 /* left_glyph :: The index of the left glyph in the kern pair. */
72 /* */
73 /* right_glyph :: The index of the right glyph in the kern pair. */
74 /* */
75 /* <Output> */
76 /* kerning :: The kerning vector. This is in font units for */
77 /* scalable formats, and in pixels for fixed-sizes */
78 /* formats. */
79 /* */
80 /* <Return> */
81 /* FreeType error code. 0 means success. */
82 /* */
83 /* <Note> */
84 /* Only horizontal layouts (left-to-right & right-to-left) are */
85 /* supported by this function. Other layouts, or more sophisticated */
86 /* kernings, are out of scope of this method (the basic driver */
87 /* interface is meant to be simple). */
88 /* */
89 /* They can be implemented by format-specific interfaces. */
90 /* */
91 static FT_Error
92 Get_Kerning( TT_Face face,
93 FT_UInt left_glyph,
94 FT_UInt right_glyph,
95 FT_Vector* kerning )
96 {
97 TT_Kern_0_Pair* pair;
100 if ( !face )
101 return TT_Err_Invalid_Face_Handle;
103 kerning->x = 0;
104 kerning->y = 0;
106 if ( face->kern_pairs )
107 {
108 /* there are some kerning pairs in this font file! */
109 FT_ULong search_tag = PAIR_TAG( left_glyph, right_glyph );
110 FT_Long left, right;
113 left = 0;
114 right = face->num_kern_pairs - 1;
116 while ( left <= right )
117 {
118 FT_Int middle = left + ( ( right - left ) >> 1 );
119 FT_ULong cur_pair;
122 pair = face->kern_pairs + middle;
123 cur_pair = PAIR_TAG( pair->left, pair->right );
125 if ( cur_pair == search_tag )
126 goto Found;
128 if ( cur_pair < search_tag )
129 left = middle + 1;
130 else
131 right = middle - 1;
132 }
133 }
135 Exit:
136 return TT_Err_Ok;
138 Found:
139 kerning->x = pair->value;
140 goto Exit;
141 }
144 #undef PAIR_TAG
147 /*************************************************************************/
148 /*************************************************************************/
149 /*************************************************************************/
150 /**** ****/
151 /**** ****/
152 /**** S I Z E S ****/
153 /**** ****/
154 /**** ****/
155 /*************************************************************************/
156 /*************************************************************************/
157 /*************************************************************************/
160 /*************************************************************************/
161 /* */
162 /* <Function> */
163 /* Set_Char_Sizes */
164 /* */
165 /* <Description> */
166 /* A driver method used to reset a size's character sizes (horizontal */
167 /* and vertical) expressed in fractional points. */
168 /* */
169 /* <Input> */
170 /* char_width :: The character width expressed in 26.6 */
171 /* fractional points. */
172 /* */
173 /* char_height :: The character height expressed in 26.6 */
174 /* fractional points. */
175 /* */
176 /* horz_resolution :: The horizontal resolution of the output device. */
177 /* */
178 /* vert_resolution :: The vertical resolution of the output device. */
179 /* */
180 /* <InOut> */
181 /* size :: A handle to the target size object. */
182 /* */
183 /* <Return> */
184 /* FreeType error code. 0 means success. */
185 /* */
186 static FT_Error
187 Set_Char_Sizes( TT_Size size,
188 FT_F26Dot6 char_width,
189 FT_F26Dot6 char_height,
190 FT_UInt horz_resolution,
191 FT_UInt vert_resolution )
192 {
193 FT_Size_Metrics* metrics = &size->root.metrics;
194 TT_Face face = (TT_Face)size->root.face;
195 FT_Long dim_x, dim_y;
198 /* This bit flag, when set, indicates that the pixel size must be */
199 /* truncated to an integer. Nearly all TrueType fonts have this */
200 /* bit set, as hinting won't work really well otherwise. */
201 /* */
202 /* However, for those rare fonts who do not set it, we override */
203 /* the default computations performed by the base layer. I */
204 /* really don't know whether this is useful, but hey, that's the */
205 /* spec :-) */
206 /* */
207 if ( ( face->header.Flags & 8 ) == 0 )
208 {
209 /* Compute pixel sizes in 26.6 units */
210 dim_x = ( char_width * horz_resolution ) / 72;
211 dim_y = ( char_height * vert_resolution ) / 72;
213 metrics->x_scale = FT_DivFix( dim_x, face->root.units_per_EM );
214 metrics->y_scale = FT_DivFix( dim_y, face->root.units_per_EM );
216 metrics->x_ppem = (FT_UShort)( dim_x >> 6 );
217 metrics->y_ppem = (FT_UShort)( dim_y >> 6 );
218 }
220 size->ttmetrics.valid = FALSE;
221 #ifdef TT_CONFIG_OPTION_EMBEDDED_BITMAPS
222 size->strike_index = 0xFFFF;
223 #endif
225 return TT_Reset_Size( size );
226 }
229 /*************************************************************************/
230 /* */
231 /* <Function> */
232 /* Set_Pixel_Sizes */
233 /* */
234 /* <Description> */
235 /* A driver method used to reset a size's character sizes (horizontal */
236 /* and vertical) expressed in integer pixels. */
237 /* */
238 /* <Input> */
239 /* pixel_width :: The character width expressed in integer pixels. */
240 /* */
241 /* pixel_height :: The character height expressed in integer pixels. */
242 /* */
243 /* <InOut> */
244 /* size :: A handle to the target size object. */
245 /* */
246 /* <Return> */
247 /* FreeType error code. 0 means success. */
248 /* */
249 static FT_Error
250 Set_Pixel_Sizes( TT_Size size,
251 FT_UInt pixel_width,
252 FT_UInt pixel_height )
253 {
254 FT_UNUSED( pixel_width );
255 FT_UNUSED( pixel_height );
257 /* many things have been pre-computed by the base layer */
259 size->ttmetrics.valid = FALSE;
260 #ifdef TT_CONFIG_OPTION_EMBEDDED_BITMAPS
261 size->strike_index = 0xFFFF;
262 #endif
264 return TT_Reset_Size( size );
265 }
268 /*************************************************************************/
269 /* */
270 /* <Function> */
271 /* Load_Glyph */
272 /* */
273 /* <Description> */
274 /* A driver method used to load a glyph within a given glyph slot. */
275 /* */
276 /* <Input> */
277 /* slot :: A handle to the target slot object where the glyph */
278 /* will be loaded. */
279 /* */
280 /* size :: A handle to the source face size at which the glyph */
281 /* must be scaled, loaded, etc. */
282 /* */
283 /* glyph_index :: The index of the glyph in the font file. */
284 /* */
285 /* load_flags :: A flag indicating what to load for this glyph. The */
286 /* FTLOAD_??? constants can be used to control the */
287 /* glyph loading process (e.g., whether the outline */
288 /* should be scaled, whether to load bitmaps or not, */
289 /* whether to hint the outline, etc). */
290 /* */
291 /* <Return> */
292 /* FreeType error code. 0 means success. */
293 /* */
294 static FT_Error
295 Load_Glyph( TT_GlyphSlot slot,
296 TT_Size size,
297 FT_UShort glyph_index,
298 FT_UInt load_flags )
299 {
300 FT_Error error;
303 if ( !slot )
304 return TT_Err_Invalid_Slot_Handle;
306 /* check whether we want a scaled outline or bitmap */
307 if ( !size )
308 load_flags |= FT_LOAD_NO_SCALE | FT_LOAD_NO_HINTING;
310 if ( load_flags & FT_LOAD_NO_SCALE )
311 size = NULL;
313 /* reset the size object if necessary */
314 if ( size )
315 {
316 /* these two object must have the same parent */
317 if ( size->root.face != slot->face )
318 return TT_Err_Invalid_Face_Handle;
320 if ( !size->ttmetrics.valid )
321 {
322 if ( FT_SET_ERROR( TT_Reset_Size( size ) ) )
323 return error;
324 }
325 }
327 /* now load the glyph outline if necessary */
328 error = TT_Load_Glyph( size, slot, glyph_index, load_flags );
330 /* force drop-out mode to 2 - irrelevant now */
331 /* slot->outline.dropout_mode = 2; */
333 return error;
334 }
337 /*************************************************************************/
338 /*************************************************************************/
339 /*************************************************************************/
340 /**** ****/
341 /**** ****/
342 /**** C H A R A C T E R M A P P I N G S ****/
343 /**** ****/
344 /**** ****/
345 /*************************************************************************/
346 /*************************************************************************/
347 /*************************************************************************/
349 /*************************************************************************/
350 /* */
351 /* <Function> */
352 /* Get_Char_Index */
353 /* */
354 /* <Description> */
355 /* Uses a charmap to return a given character code's glyph index. */
356 /* */
357 /* <Input> */
358 /* charmap :: A handle to the source charmap object. */
359 /* charcode :: The character code. */
360 /* */
361 /* <Return> */
362 /* Glyph index. 0 means `undefined character code'. */
363 /* */
364 static FT_UInt
365 Get_Char_Index( TT_CharMap charmap,
366 FT_Long charcode )
367 {
368 FT_Error error;
369 TT_Face face;
370 TT_CMapTable* cmap;
373 cmap = &charmap->cmap;
374 face = (TT_Face)charmap->root.face;
376 /* Load table if needed */
377 if ( !cmap->loaded )
378 {
379 SFNT_Interface* sfnt = (SFNT_Interface*)face->sfnt;
382 error = sfnt->load_charmap( face, cmap, face->root.stream );
383 if ( error )
384 return 0;
386 cmap->loaded = TRUE;
387 }
389 if ( cmap->get_index )
390 return cmap->get_index( cmap, charcode );
391 else
392 return 0;
393 }
396 /*************************************************************************/
397 /*************************************************************************/
398 /*************************************************************************/
399 /**** ****/
400 /**** ****/
401 /**** D R I V E R I N T E R F A C E ****/
402 /**** ****/
403 /**** ****/
404 /*************************************************************************/
405 /*************************************************************************/
406 /*************************************************************************/
409 static FT_Module_Interface
410 tt_get_interface( TT_Driver driver,
411 const char* interface )
412 {
413 FT_Module sfntd = FT_Get_Module( driver->root.root.library,
414 "sfnt" );
415 SFNT_Interface* sfnt;
418 /* only return the default interface from the SFNT module */
419 if ( sfntd )
420 {
421 sfnt = (SFNT_Interface*)( sfntd->clazz->module_interface );
422 if ( sfnt )
423 return sfnt->get_interface( FT_MODULE( driver ), interface );
424 }
426 return 0;
427 }
430 /* The FT_DriverInterface structure is defined in ftdriver.h. */
432 FT_CALLBACK_TABLE_DEF
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
444 sizeof ( TT_DriverRec ),
446 "truetype", /* driver name */
447 0x10000L, /* driver version == 1.0 */
448 0x20000L, /* driver requires FreeType 2.0 or above */
450 (void*)0, /* driver specific interface */
452 (FT_Module_Constructor)TT_Init_Driver,
453 (FT_Module_Destructor) TT_Done_Driver,
454 (FT_Module_Requester) tt_get_interface,
455 },
457 sizeof ( TT_FaceRec ),
458 sizeof ( TT_SizeRec ),
459 sizeof ( FT_GlyphSlotRec ),
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,
469 (FTDriver_setCharSizes) Set_Char_Sizes,
470 (FTDriver_setPixelSizes)Set_Pixel_Sizes,
471 (FTDriver_loadGlyph) Load_Glyph,
472 (FTDriver_getCharIndex) Get_Char_Index,
474 (FTDriver_getKerning) Get_Kerning,
475 (FTDriver_attachFile) 0,
476 (FTDriver_getAdvances) 0
477 };
480 #ifdef FT_CONFIG_OPTION_DYNAMIC_DRIVERS
483 /*************************************************************************/
484 /* */
485 /* <Function> */
486 /* getDriverClass */
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 FT_EXPORT_DEF( const FT_Driver_Class* )
503 getDriverClass( void )
504 {
505 return &tt_driver_class;
506 }
509 #endif /* CONFIG_OPTION_DYNAMIC_DRIVERS */
512 /* END */