• Home
  • Line#
  • Scopes#
  • Navigate#
  • Raw
  • Download
1 /*
2  * Copyright © 2009  Red Hat, Inc.
3  * Copyright © 2011  Google, Inc.
4  *
5  *  This is part of HarfBuzz, a text shaping 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  * Red Hat Author(s): Behdad Esfahbod
26  * Google Author(s): Behdad Esfahbod
27  */
28 
29 #ifndef HB_FONT_HH
30 #define HB_FONT_HH
31 
32 #include "hb.hh"
33 
34 #include "hb-face.hh"
35 #include "hb-shaper.hh"
36 
37 
38 /*
39  * hb_font_funcs_t
40  */
41 
42 #define HB_FONT_FUNCS_IMPLEMENT_CALLBACKS \
43   HB_FONT_FUNC_IMPLEMENT (font_h_extents) \
44   HB_FONT_FUNC_IMPLEMENT (font_v_extents) \
45   HB_FONT_FUNC_IMPLEMENT (nominal_glyph) \
46   HB_FONT_FUNC_IMPLEMENT (nominal_glyphs) \
47   HB_FONT_FUNC_IMPLEMENT (variation_glyph) \
48   HB_FONT_FUNC_IMPLEMENT (glyph_h_advance) \
49   HB_FONT_FUNC_IMPLEMENT (glyph_v_advance) \
50   HB_FONT_FUNC_IMPLEMENT (glyph_h_advances) \
51   HB_FONT_FUNC_IMPLEMENT (glyph_v_advances) \
52   HB_FONT_FUNC_IMPLEMENT (glyph_h_origin) \
53   HB_FONT_FUNC_IMPLEMENT (glyph_v_origin) \
54   HB_FONT_FUNC_IMPLEMENT (glyph_h_kerning) \
55   HB_IF_NOT_DEPRECATED (HB_FONT_FUNC_IMPLEMENT (glyph_v_kerning)) \
56   HB_FONT_FUNC_IMPLEMENT (glyph_extents) \
57   HB_FONT_FUNC_IMPLEMENT (glyph_contour_point) \
58   HB_FONT_FUNC_IMPLEMENT (glyph_name) \
59   HB_FONT_FUNC_IMPLEMENT (glyph_from_name) \
60   /* ^--- Add new callbacks here */
61 
62 struct hb_font_funcs_t
63 {
64   hb_object_header_t header;
65 
66   struct {
67 #define HB_FONT_FUNC_IMPLEMENT(name) void *name;
68     HB_FONT_FUNCS_IMPLEMENT_CALLBACKS
69 #undef HB_FONT_FUNC_IMPLEMENT
70   } user_data;
71 
72   struct {
73 #define HB_FONT_FUNC_IMPLEMENT(name) hb_destroy_func_t name;
74     HB_FONT_FUNCS_IMPLEMENT_CALLBACKS
75 #undef HB_FONT_FUNC_IMPLEMENT
76   } destroy;
77 
78   /* Don't access these directly.  Call font->get_*() instead. */
79   union get_t {
80     struct get_funcs_t {
81 #define HB_FONT_FUNC_IMPLEMENT(name) hb_font_get_##name##_func_t name;
82       HB_FONT_FUNCS_IMPLEMENT_CALLBACKS
83 #undef HB_FONT_FUNC_IMPLEMENT
84     } f;
85     void (*array[0
86 #define HB_FONT_FUNC_IMPLEMENT(name) +1
87       HB_FONT_FUNCS_IMPLEMENT_CALLBACKS
88 #undef HB_FONT_FUNC_IMPLEMENT
89 		]) ();
90   } get;
91 };
92 DECLARE_NULL_INSTANCE (hb_font_funcs_t);
93 
94 
95 /*
96  * hb_font_t
97  */
98 
99 #define HB_SHAPER_IMPLEMENT(shaper) HB_SHAPER_DATA_INSTANTIATE_SHAPERS(shaper, font);
100 #include "hb-shaper-list.hh"
101 #undef HB_SHAPER_IMPLEMENT
102 
103 struct hb_font_t
104 {
105   hb_object_header_t header;
106 
107   hb_font_t *parent;
108   hb_face_t *face;
109 
110   int32_t x_scale;
111   int32_t y_scale;
112   int64_t x_mult;
113   int64_t y_mult;
114 
115   unsigned int x_ppem;
116   unsigned int y_ppem;
117 
118   float ptem;
119 
120   /* Font variation coordinates. */
121   unsigned int num_coords;
122   int *coords;
123   float *design_coords;
124 
125   hb_font_funcs_t   *klass;
126   void              *user_data;
127   hb_destroy_func_t  destroy;
128 
129   hb_shaper_object_dataset_t<hb_font_t> data; /* Various shaper data. */
130 
131 
132   /* Convert from font-space to user-space */
dir_multhb_font_t133   int64_t dir_mult (hb_direction_t direction)
134   { return HB_DIRECTION_IS_VERTICAL(direction) ? y_mult : x_mult; }
em_scale_xhb_font_t135   hb_position_t em_scale_x (int16_t v) { return em_mult (v, x_mult); }
em_scale_yhb_font_t136   hb_position_t em_scale_y (int16_t v) { return em_mult (v, y_mult); }
em_scalef_xhb_font_t137   hb_position_t em_scalef_x (float v) { return em_scalef (v, x_scale); }
em_scalef_yhb_font_t138   hb_position_t em_scalef_y (float v) { return em_scalef (v, y_scale); }
em_fscale_xhb_font_t139   float em_fscale_x (int16_t v) { return em_fscale (v, x_scale); }
em_fscale_yhb_font_t140   float em_fscale_y (int16_t v) { return em_fscale (v, y_scale); }
em_scale_dirhb_font_t141   hb_position_t em_scale_dir (int16_t v, hb_direction_t direction)
142   { return em_mult (v, dir_mult (direction)); }
143 
144   /* Convert from parent-font user-space to our user-space */
parent_scale_x_distancehb_font_t145   hb_position_t parent_scale_x_distance (hb_position_t v)
146   {
147     if (unlikely (parent && parent->x_scale != x_scale))
148       return (hb_position_t) (v * (int64_t) this->x_scale / this->parent->x_scale);
149     return v;
150   }
parent_scale_y_distancehb_font_t151   hb_position_t parent_scale_y_distance (hb_position_t v)
152   {
153     if (unlikely (parent && parent->y_scale != y_scale))
154       return (hb_position_t) (v * (int64_t) this->y_scale / this->parent->y_scale);
155     return v;
156   }
parent_scale_x_positionhb_font_t157   hb_position_t parent_scale_x_position (hb_position_t v)
158   { return parent_scale_x_distance (v); }
parent_scale_y_positionhb_font_t159   hb_position_t parent_scale_y_position (hb_position_t v)
160   { return parent_scale_y_distance (v); }
161 
parent_scale_distancehb_font_t162   void parent_scale_distance (hb_position_t *x, hb_position_t *y)
163   {
164     *x = parent_scale_x_distance (*x);
165     *y = parent_scale_y_distance (*y);
166   }
parent_scale_positionhb_font_t167   void parent_scale_position (hb_position_t *x, hb_position_t *y)
168   {
169     *x = parent_scale_x_position (*x);
170     *y = parent_scale_y_position (*y);
171   }
172 
173 
174   /* Public getters */
175 
176   HB_INTERNAL bool has_func (unsigned int i);
177   HB_INTERNAL bool has_func_set (unsigned int i);
178 
179   /* has_* ... */
180 #define HB_FONT_FUNC_IMPLEMENT(name) \
181   bool \
182   has_##name##_func () \
183   { \
184     hb_font_funcs_t *funcs = this->klass; \
185     unsigned int i = offsetof (hb_font_funcs_t::get_t::get_funcs_t, name) / sizeof (funcs->get.array[0]); \
186     return has_func (i); \
187   } \
188   bool \
189   has_##name##_func_set () \
190   { \
191     hb_font_funcs_t *funcs = this->klass; \
192     unsigned int i = offsetof (hb_font_funcs_t::get_t::get_funcs_t, name) / sizeof (funcs->get.array[0]); \
193     return has_func_set (i); \
194   }
195   HB_FONT_FUNCS_IMPLEMENT_CALLBACKS
196 #undef HB_FONT_FUNC_IMPLEMENT
197 
get_font_h_extentshb_font_t198   hb_bool_t get_font_h_extents (hb_font_extents_t *extents)
199   {
200     memset (extents, 0, sizeof (*extents));
201     return klass->get.f.font_h_extents (this, user_data,
202 					extents,
203 					klass->user_data.font_h_extents);
204   }
get_font_v_extentshb_font_t205   hb_bool_t get_font_v_extents (hb_font_extents_t *extents)
206   {
207     memset (extents, 0, sizeof (*extents));
208     return klass->get.f.font_v_extents (this, user_data,
209 					extents,
210 					klass->user_data.font_v_extents);
211   }
212 
has_glyphhb_font_t213   bool has_glyph (hb_codepoint_t unicode)
214   {
215     hb_codepoint_t glyph;
216     return get_nominal_glyph (unicode, &glyph);
217   }
218 
get_nominal_glyphhb_font_t219   hb_bool_t get_nominal_glyph (hb_codepoint_t unicode,
220 			       hb_codepoint_t *glyph,
221 			       hb_codepoint_t not_found = 0)
222   {
223     *glyph = not_found;
224     return klass->get.f.nominal_glyph (this, user_data,
225 				       unicode, glyph,
226 				       klass->user_data.nominal_glyph);
227   }
get_nominal_glyphshb_font_t228   unsigned int get_nominal_glyphs (unsigned int count,
229 				   const hb_codepoint_t *first_unicode,
230 				   unsigned int unicode_stride,
231 				   hb_codepoint_t *first_glyph,
232 				   unsigned int glyph_stride)
233   {
234     return klass->get.f.nominal_glyphs (this, user_data,
235 					count,
236 					first_unicode, unicode_stride,
237 					first_glyph, glyph_stride,
238 					klass->user_data.nominal_glyphs);
239   }
240 
get_variation_glyphhb_font_t241   hb_bool_t get_variation_glyph (hb_codepoint_t unicode, hb_codepoint_t variation_selector,
242 				 hb_codepoint_t *glyph,
243 				 hb_codepoint_t not_found = 0)
244   {
245     *glyph = not_found;
246     return klass->get.f.variation_glyph (this, user_data,
247 					 unicode, variation_selector, glyph,
248 					 klass->user_data.variation_glyph);
249   }
250 
get_glyph_h_advancehb_font_t251   hb_position_t get_glyph_h_advance (hb_codepoint_t glyph)
252   {
253     return klass->get.f.glyph_h_advance (this, user_data,
254 					 glyph,
255 					 klass->user_data.glyph_h_advance);
256   }
257 
get_glyph_v_advancehb_font_t258   hb_position_t get_glyph_v_advance (hb_codepoint_t glyph)
259   {
260     return klass->get.f.glyph_v_advance (this, user_data,
261 					 glyph,
262 					 klass->user_data.glyph_v_advance);
263   }
264 
get_glyph_h_advanceshb_font_t265   void get_glyph_h_advances (unsigned int count,
266 			     const hb_codepoint_t *first_glyph,
267 			     unsigned int glyph_stride,
268 			     hb_position_t *first_advance,
269 			     unsigned int advance_stride)
270   {
271     return klass->get.f.glyph_h_advances (this, user_data,
272 					  count,
273 					  first_glyph, glyph_stride,
274 					  first_advance, advance_stride,
275 					  klass->user_data.glyph_h_advances);
276   }
277 
get_glyph_v_advanceshb_font_t278   void get_glyph_v_advances (unsigned int count,
279 			     const hb_codepoint_t *first_glyph,
280 			     unsigned int glyph_stride,
281 			     hb_position_t *first_advance,
282 			     unsigned int advance_stride)
283   {
284     return klass->get.f.glyph_v_advances (this, user_data,
285 					  count,
286 					  first_glyph, glyph_stride,
287 					  first_advance, advance_stride,
288 					  klass->user_data.glyph_v_advances);
289   }
290 
get_glyph_h_originhb_font_t291   hb_bool_t get_glyph_h_origin (hb_codepoint_t glyph,
292 				hb_position_t *x, hb_position_t *y)
293   {
294     *x = *y = 0;
295     return klass->get.f.glyph_h_origin (this, user_data,
296 					glyph, x, y,
297 					klass->user_data.glyph_h_origin);
298   }
299 
get_glyph_v_originhb_font_t300   hb_bool_t get_glyph_v_origin (hb_codepoint_t glyph,
301 				hb_position_t *x, hb_position_t *y)
302   {
303     *x = *y = 0;
304     return klass->get.f.glyph_v_origin (this, user_data,
305 					glyph, x, y,
306 					klass->user_data.glyph_v_origin);
307   }
308 
get_glyph_h_kerninghb_font_t309   hb_position_t get_glyph_h_kerning (hb_codepoint_t left_glyph,
310 				     hb_codepoint_t right_glyph)
311   {
312 #ifdef HB_DISABLE_DEPRECATED
313     return 0;
314 #else
315     return klass->get.f.glyph_h_kerning (this, user_data,
316 					 left_glyph, right_glyph,
317 					 klass->user_data.glyph_h_kerning);
318 #endif
319   }
320 
get_glyph_v_kerninghb_font_t321   hb_position_t get_glyph_v_kerning (hb_codepoint_t top_glyph,
322 				     hb_codepoint_t bottom_glyph)
323   {
324 #ifdef HB_DISABLE_DEPRECATED
325     return 0;
326 #else
327     return klass->get.f.glyph_v_kerning (this, user_data,
328 					 top_glyph, bottom_glyph,
329 					 klass->user_data.glyph_v_kerning);
330 #endif
331   }
332 
get_glyph_extentshb_font_t333   hb_bool_t get_glyph_extents (hb_codepoint_t glyph,
334 			       hb_glyph_extents_t *extents)
335   {
336     memset (extents, 0, sizeof (*extents));
337     return klass->get.f.glyph_extents (this, user_data,
338 				       glyph,
339 				       extents,
340 				       klass->user_data.glyph_extents);
341   }
342 
get_glyph_contour_pointhb_font_t343   hb_bool_t get_glyph_contour_point (hb_codepoint_t glyph, unsigned int point_index,
344 				     hb_position_t *x, hb_position_t *y)
345   {
346     *x = *y = 0;
347     return klass->get.f.glyph_contour_point (this, user_data,
348 					     glyph, point_index,
349 					     x, y,
350 					     klass->user_data.glyph_contour_point);
351   }
352 
get_glyph_namehb_font_t353   hb_bool_t get_glyph_name (hb_codepoint_t glyph,
354 			    char *name, unsigned int size)
355   {
356     if (size) *name = '\0';
357     return klass->get.f.glyph_name (this, user_data,
358 				    glyph,
359 				    name, size,
360 				    klass->user_data.glyph_name);
361   }
362 
get_glyph_from_namehb_font_t363   hb_bool_t get_glyph_from_name (const char *name, int len, /* -1 means nul-terminated */
364 				 hb_codepoint_t *glyph)
365   {
366     *glyph = 0;
367     if (len == -1) len = strlen (name);
368     return klass->get.f.glyph_from_name (this, user_data,
369 					 name, len,
370 					 glyph,
371 					 klass->user_data.glyph_from_name);
372   }
373 
374 
375   /* A bit higher-level, and with fallback */
376 
get_h_extents_with_fallbackhb_font_t377   void get_h_extents_with_fallback (hb_font_extents_t *extents)
378   {
379     if (!get_font_h_extents (extents))
380     {
381       extents->ascender = y_scale * .8;
382       extents->descender = extents->ascender - y_scale;
383       extents->line_gap = 0;
384     }
385   }
get_v_extents_with_fallbackhb_font_t386   void get_v_extents_with_fallback (hb_font_extents_t *extents)
387   {
388     if (!get_font_v_extents (extents))
389     {
390       extents->ascender = x_scale / 2;
391       extents->descender = extents->ascender - x_scale;
392       extents->line_gap = 0;
393     }
394   }
395 
get_extents_for_directionhb_font_t396   void get_extents_for_direction (hb_direction_t direction,
397 				  hb_font_extents_t *extents)
398   {
399     if (likely (HB_DIRECTION_IS_HORIZONTAL (direction)))
400       get_h_extents_with_fallback (extents);
401     else
402       get_v_extents_with_fallback (extents);
403   }
404 
get_glyph_advance_for_directionhb_font_t405   void get_glyph_advance_for_direction (hb_codepoint_t glyph,
406 					hb_direction_t direction,
407 					hb_position_t *x, hb_position_t *y)
408   {
409     *x = *y = 0;
410     if (likely (HB_DIRECTION_IS_HORIZONTAL (direction)))
411       *x = get_glyph_h_advance (glyph);
412     else
413       *y = get_glyph_v_advance (glyph);
414   }
get_glyph_advances_for_directionhb_font_t415   void get_glyph_advances_for_direction (hb_direction_t direction,
416 					 unsigned int count,
417 					 const hb_codepoint_t *first_glyph,
418 					 unsigned glyph_stride,
419 					 hb_position_t *first_advance,
420 					 unsigned advance_stride)
421   {
422     if (likely (HB_DIRECTION_IS_HORIZONTAL (direction)))
423       get_glyph_h_advances (count, first_glyph, glyph_stride, first_advance, advance_stride);
424     else
425       get_glyph_v_advances (count, first_glyph, glyph_stride, first_advance, advance_stride);
426   }
427 
guess_v_origin_minus_h_originhb_font_t428   void guess_v_origin_minus_h_origin (hb_codepoint_t glyph,
429 				      hb_position_t *x, hb_position_t *y)
430   {
431     *x = get_glyph_h_advance (glyph) / 2;
432 
433     /* TODO cache this somehow?! */
434     hb_font_extents_t extents;
435     get_h_extents_with_fallback (&extents);
436     *y = extents.ascender;
437   }
438 
get_glyph_h_origin_with_fallbackhb_font_t439   void get_glyph_h_origin_with_fallback (hb_codepoint_t glyph,
440 					 hb_position_t *x, hb_position_t *y)
441   {
442     if (!get_glyph_h_origin (glyph, x, y) &&
443 	 get_glyph_v_origin (glyph, x, y))
444     {
445       hb_position_t dx, dy;
446       guess_v_origin_minus_h_origin (glyph, &dx, &dy);
447       *x -= dx; *y -= dy;
448     }
449   }
get_glyph_v_origin_with_fallbackhb_font_t450   void get_glyph_v_origin_with_fallback (hb_codepoint_t glyph,
451 					 hb_position_t *x, hb_position_t *y)
452   {
453     if (!get_glyph_v_origin (glyph, x, y) &&
454 	 get_glyph_h_origin (glyph, x, y))
455     {
456       hb_position_t dx, dy;
457       guess_v_origin_minus_h_origin (glyph, &dx, &dy);
458       *x += dx; *y += dy;
459     }
460   }
461 
get_glyph_origin_for_directionhb_font_t462   void get_glyph_origin_for_direction (hb_codepoint_t glyph,
463 				       hb_direction_t direction,
464 				       hb_position_t *x, hb_position_t *y)
465   {
466     if (likely (HB_DIRECTION_IS_HORIZONTAL (direction)))
467       get_glyph_h_origin_with_fallback (glyph, x, y);
468     else
469       get_glyph_v_origin_with_fallback (glyph, x, y);
470   }
471 
add_glyph_h_originhb_font_t472   void add_glyph_h_origin (hb_codepoint_t glyph,
473 			   hb_position_t *x, hb_position_t *y)
474   {
475     hb_position_t origin_x, origin_y;
476 
477     get_glyph_h_origin_with_fallback (glyph, &origin_x, &origin_y);
478 
479     *x += origin_x;
480     *y += origin_y;
481   }
add_glyph_v_originhb_font_t482   void add_glyph_v_origin (hb_codepoint_t glyph,
483 			   hb_position_t *x, hb_position_t *y)
484   {
485     hb_position_t origin_x, origin_y;
486 
487     get_glyph_v_origin_with_fallback (glyph, &origin_x, &origin_y);
488 
489     *x += origin_x;
490     *y += origin_y;
491   }
add_glyph_origin_for_directionhb_font_t492   void add_glyph_origin_for_direction (hb_codepoint_t glyph,
493 				       hb_direction_t direction,
494 				       hb_position_t *x, hb_position_t *y)
495   {
496     hb_position_t origin_x, origin_y;
497 
498     get_glyph_origin_for_direction (glyph, direction, &origin_x, &origin_y);
499 
500     *x += origin_x;
501     *y += origin_y;
502   }
503 
subtract_glyph_h_originhb_font_t504   void subtract_glyph_h_origin (hb_codepoint_t glyph,
505 				hb_position_t *x, hb_position_t *y)
506   {
507     hb_position_t origin_x, origin_y;
508 
509     get_glyph_h_origin_with_fallback (glyph, &origin_x, &origin_y);
510 
511     *x -= origin_x;
512     *y -= origin_y;
513   }
subtract_glyph_v_originhb_font_t514   void subtract_glyph_v_origin (hb_codepoint_t glyph,
515 				hb_position_t *x, hb_position_t *y)
516   {
517     hb_position_t origin_x, origin_y;
518 
519     get_glyph_v_origin_with_fallback (glyph, &origin_x, &origin_y);
520 
521     *x -= origin_x;
522     *y -= origin_y;
523   }
subtract_glyph_origin_for_directionhb_font_t524   void subtract_glyph_origin_for_direction (hb_codepoint_t glyph,
525 					    hb_direction_t direction,
526 					    hb_position_t *x, hb_position_t *y)
527   {
528     hb_position_t origin_x, origin_y;
529 
530     get_glyph_origin_for_direction (glyph, direction, &origin_x, &origin_y);
531 
532     *x -= origin_x;
533     *y -= origin_y;
534   }
535 
get_glyph_kerning_for_directionhb_font_t536   void get_glyph_kerning_for_direction (hb_codepoint_t first_glyph, hb_codepoint_t second_glyph,
537 					hb_direction_t direction,
538 					hb_position_t *x, hb_position_t *y)
539   {
540     if (likely (HB_DIRECTION_IS_HORIZONTAL (direction))) {
541       *y = 0;
542       *x = get_glyph_h_kerning (first_glyph, second_glyph);
543     } else {
544       *x = 0;
545       *y = get_glyph_v_kerning (first_glyph, second_glyph);
546     }
547   }
548 
get_glyph_extents_for_originhb_font_t549   hb_bool_t get_glyph_extents_for_origin (hb_codepoint_t glyph,
550 					  hb_direction_t direction,
551 					  hb_glyph_extents_t *extents)
552   {
553     hb_bool_t ret = get_glyph_extents (glyph, extents);
554 
555     if (ret)
556       subtract_glyph_origin_for_direction (glyph, direction, &extents->x_bearing, &extents->y_bearing);
557 
558     return ret;
559   }
560 
get_glyph_contour_point_for_originhb_font_t561   hb_bool_t get_glyph_contour_point_for_origin (hb_codepoint_t glyph, unsigned int point_index,
562 						hb_direction_t direction,
563 						hb_position_t *x, hb_position_t *y)
564   {
565     hb_bool_t ret = get_glyph_contour_point (glyph, point_index, x, y);
566 
567     if (ret)
568       subtract_glyph_origin_for_direction (glyph, direction, x, y);
569 
570     return ret;
571   }
572 
573   /* Generates gidDDD if glyph has no name. */
574   void
glyph_to_stringhb_font_t575   glyph_to_string (hb_codepoint_t glyph,
576 		   char *s, unsigned int size)
577   {
578     if (get_glyph_name (glyph, s, size)) return;
579 
580     if (size && snprintf (s, size, "gid%u", glyph) < 0)
581       *s = '\0';
582   }
583 
584   /* Parses gidDDD and uniUUUU strings automatically. */
585   hb_bool_t
glyph_from_stringhb_font_t586   glyph_from_string (const char *s, int len, /* -1 means nul-terminated */
587 		     hb_codepoint_t *glyph)
588   {
589     if (get_glyph_from_name (s, len, glyph)) return true;
590 
591     if (len == -1) len = strlen (s);
592 
593     /* Straight glyph index. */
594     if (hb_codepoint_parse (s, len, 10, glyph))
595       return true;
596 
597     if (len > 3)
598     {
599       /* gidDDD syntax for glyph indices. */
600       if (0 == strncmp (s, "gid", 3) &&
601 	  hb_codepoint_parse (s + 3, len - 3, 10, glyph))
602 	return true;
603 
604       /* uniUUUU and other Unicode character indices. */
605       hb_codepoint_t unichar;
606       if (0 == strncmp (s, "uni", 3) &&
607 	  hb_codepoint_parse (s + 3, len - 3, 16, &unichar) &&
608 	  get_nominal_glyph (unichar, glyph))
609 	return true;
610     }
611 
612     return false;
613   }
614 
mults_changedhb_font_t615   void mults_changed ()
616   {
617     signed upem = face->get_upem ();
618     x_mult = ((int64_t) x_scale << 16) / upem;
619     y_mult = ((int64_t) y_scale << 16) / upem;
620   }
621 
em_multhb_font_t622   hb_position_t em_mult (int16_t v, int64_t mult)
623   { return (hb_position_t) ((v * mult + 32768) >> 16); }
em_scalefhb_font_t624   hb_position_t em_scalef (float v, int scale)
625   { return (hb_position_t) roundf (v * scale / face->get_upem ()); }
em_fscalehb_font_t626   float em_fscale (int16_t v, int scale)
627   { return (float) v * scale / face->get_upem (); }
628 };
629 DECLARE_NULL_INSTANCE (hb_font_t);
630 
631 
632 #endif /* HB_FONT_HH */
633