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_PRIVATE_HH
30 #define HB_FONT_PRIVATE_HH
31 
32 #include "hb-private.hh"
33 
34 #include "hb-object-private.hh"
35 #include "hb-face-private.hh"
36 #include "hb-shaper-private.hh"
37 
38 
39 
40 /*
41  * hb_font_funcs_t
42  */
43 
44 #define HB_FONT_FUNCS_IMPLEMENT_CALLBACKS \
45   HB_FONT_FUNC_IMPLEMENT (font_h_extents) \
46   HB_FONT_FUNC_IMPLEMENT (font_v_extents) \
47   HB_FONT_FUNC_IMPLEMENT (nominal_glyph) \
48   HB_FONT_FUNC_IMPLEMENT (variation_glyph) \
49   HB_FONT_FUNC_IMPLEMENT (glyph_h_advance) \
50   HB_FONT_FUNC_IMPLEMENT (glyph_v_advance) \
51   HB_FONT_FUNC_IMPLEMENT (glyph_h_origin) \
52   HB_FONT_FUNC_IMPLEMENT (glyph_v_origin) \
53   HB_FONT_FUNC_IMPLEMENT (glyph_h_kerning) \
54   HB_FONT_FUNC_IMPLEMENT (glyph_v_kerning) \
55   HB_FONT_FUNC_IMPLEMENT (glyph_extents) \
56   HB_FONT_FUNC_IMPLEMENT (glyph_contour_point) \
57   HB_FONT_FUNC_IMPLEMENT (glyph_name) \
58   HB_FONT_FUNC_IMPLEMENT (glyph_from_name) \
59   /* ^--- Add new callbacks here */
60 
61 struct hb_font_funcs_t {
62   hb_object_header_t header;
63   ASSERT_POD ();
64 
65   hb_bool_t immutable;
66 
67   struct {
68 #define HB_FONT_FUNC_IMPLEMENT(name) void *name;
69     HB_FONT_FUNCS_IMPLEMENT_CALLBACKS
70 #undef HB_FONT_FUNC_IMPLEMENT
71   } user_data;
72 
73   struct {
74 #define HB_FONT_FUNC_IMPLEMENT(name) hb_destroy_func_t name;
75     HB_FONT_FUNCS_IMPLEMENT_CALLBACKS
76 #undef HB_FONT_FUNC_IMPLEMENT
77   } destroy;
78 
79   /* Don't access these directly.  Call font->get_*() instead. */
80   union get_t {
81     struct get_funcs_t {
82 #define HB_FONT_FUNC_IMPLEMENT(name) hb_font_get_##name##_func_t name;
83       HB_FONT_FUNCS_IMPLEMENT_CALLBACKS
84 #undef HB_FONT_FUNC_IMPLEMENT
85     } f;
86     void (*array[VAR]) (void);
87   } get;
88 };
89 
90 
91 
92 /*
93  * hb_font_t
94  */
95 
96 struct hb_font_t {
97   hb_object_header_t header;
98   ASSERT_POD ();
99 
100   hb_bool_t immutable;
101 
102   hb_font_t *parent;
103   hb_face_t *face;
104 
105   int x_scale;
106   int y_scale;
107 
108   unsigned int x_ppem;
109   unsigned int y_ppem;
110 
111   hb_font_funcs_t   *klass;
112   void              *user_data;
113   hb_destroy_func_t  destroy;
114 
115   struct hb_shaper_data_t shaper_data;
116 
117 
118   /* Convert from font-space to user-space */
em_scale_xhb_font_t119   inline hb_position_t em_scale_x (int16_t v) { return em_scale (v, this->x_scale); }
em_scale_yhb_font_t120   inline hb_position_t em_scale_y (int16_t v) { return em_scale (v, this->y_scale); }
121 
122   /* Convert from parent-font user-space to our user-space */
parent_scale_x_distancehb_font_t123   inline hb_position_t parent_scale_x_distance (hb_position_t v) {
124     if (unlikely (parent && parent->x_scale != x_scale))
125       return (hb_position_t) (v * (int64_t) this->x_scale / this->parent->x_scale);
126     return v;
127   }
parent_scale_y_distancehb_font_t128   inline hb_position_t parent_scale_y_distance (hb_position_t v) {
129     if (unlikely (parent && parent->y_scale != y_scale))
130       return (hb_position_t) (v * (int64_t) this->y_scale / this->parent->y_scale);
131     return v;
132   }
parent_scale_x_positionhb_font_t133   inline hb_position_t parent_scale_x_position (hb_position_t v) {
134     return parent_scale_x_distance (v);
135   }
parent_scale_y_positionhb_font_t136   inline hb_position_t parent_scale_y_position (hb_position_t v) {
137     return parent_scale_y_distance (v);
138   }
139 
parent_scale_distancehb_font_t140   inline void parent_scale_distance (hb_position_t *x, hb_position_t *y) {
141     *x = parent_scale_x_distance (*x);
142     *y = parent_scale_y_distance (*y);
143   }
parent_scale_positionhb_font_t144   inline void parent_scale_position (hb_position_t *x, hb_position_t *y) {
145     *x = parent_scale_x_position (*x);
146     *y = parent_scale_y_position (*y);
147   }
148 
149 
150   /* Public getters */
151 
152   HB_INTERNAL bool has_func (unsigned int i);
153 
154   /* has_* ... */
155 #define HB_FONT_FUNC_IMPLEMENT(name) \
156   bool \
157   has_##name##_func (void) \
158   { \
159     hb_font_funcs_t *funcs = this->klass; \
160     unsigned int i = offsetof (hb_font_funcs_t::get_t::get_funcs_t, name) / sizeof (funcs->get.array[0]); \
161     return has_func (i); \
162   }
163   HB_FONT_FUNCS_IMPLEMENT_CALLBACKS
164 #undef HB_FONT_FUNC_IMPLEMENT
165 
get_font_h_extentshb_font_t166   inline hb_bool_t get_font_h_extents (hb_font_extents_t *extents)
167   {
168     memset (extents, 0, sizeof (*extents));
169     return klass->get.f.font_h_extents (this, user_data,
170 					extents,
171 					klass->user_data.font_h_extents);
172   }
get_font_v_extentshb_font_t173   inline hb_bool_t get_font_v_extents (hb_font_extents_t *extents)
174   {
175     memset (extents, 0, sizeof (*extents));
176     return klass->get.f.font_v_extents (this, user_data,
177 					extents,
178 					klass->user_data.font_v_extents);
179   }
180 
has_glyphhb_font_t181   inline bool has_glyph (hb_codepoint_t unicode)
182   {
183     hb_codepoint_t glyph;
184     return get_nominal_glyph (unicode, &glyph);
185   }
186 
get_nominal_glyphhb_font_t187   inline hb_bool_t get_nominal_glyph (hb_codepoint_t unicode,
188 				      hb_codepoint_t *glyph)
189   {
190     *glyph = 0;
191     return klass->get.f.nominal_glyph (this, user_data,
192 				       unicode, glyph,
193 				       klass->user_data.nominal_glyph);
194   }
195 
get_variation_glyphhb_font_t196   inline hb_bool_t get_variation_glyph (hb_codepoint_t unicode, hb_codepoint_t variation_selector,
197 					hb_codepoint_t *glyph)
198   {
199     *glyph = 0;
200     return klass->get.f.variation_glyph (this, user_data,
201 					 unicode, variation_selector, glyph,
202 					 klass->user_data.variation_glyph);
203   }
204 
get_glyph_h_advancehb_font_t205   inline hb_position_t get_glyph_h_advance (hb_codepoint_t glyph)
206   {
207     return klass->get.f.glyph_h_advance (this, user_data,
208 					 glyph,
209 					 klass->user_data.glyph_h_advance);
210   }
211 
get_glyph_v_advancehb_font_t212   inline hb_position_t get_glyph_v_advance (hb_codepoint_t glyph)
213   {
214     return klass->get.f.glyph_v_advance (this, user_data,
215 					 glyph,
216 					 klass->user_data.glyph_v_advance);
217   }
218 
get_glyph_h_originhb_font_t219   inline hb_bool_t get_glyph_h_origin (hb_codepoint_t glyph,
220 				       hb_position_t *x, hb_position_t *y)
221   {
222     *x = *y = 0;
223     return klass->get.f.glyph_h_origin (this, user_data,
224 					glyph, x, y,
225 					klass->user_data.glyph_h_origin);
226   }
227 
get_glyph_v_originhb_font_t228   inline hb_bool_t get_glyph_v_origin (hb_codepoint_t glyph,
229 				       hb_position_t *x, hb_position_t *y)
230   {
231     *x = *y = 0;
232     return klass->get.f.glyph_v_origin (this, user_data,
233 					glyph, x, y,
234 					klass->user_data.glyph_v_origin);
235   }
236 
get_glyph_h_kerninghb_font_t237   inline hb_position_t get_glyph_h_kerning (hb_codepoint_t left_glyph, hb_codepoint_t right_glyph)
238   {
239     return klass->get.f.glyph_h_kerning (this, user_data,
240 					 left_glyph, right_glyph,
241 					 klass->user_data.glyph_h_kerning);
242   }
243 
get_glyph_v_kerninghb_font_t244   inline hb_position_t get_glyph_v_kerning (hb_codepoint_t top_glyph, hb_codepoint_t bottom_glyph)
245   {
246     return klass->get.f.glyph_v_kerning (this, user_data,
247 					 top_glyph, bottom_glyph,
248 					 klass->user_data.glyph_v_kerning);
249   }
250 
get_glyph_extentshb_font_t251   inline hb_bool_t get_glyph_extents (hb_codepoint_t glyph,
252 				      hb_glyph_extents_t *extents)
253   {
254     memset (extents, 0, sizeof (*extents));
255     return klass->get.f.glyph_extents (this, user_data,
256 				       glyph,
257 				       extents,
258 				       klass->user_data.glyph_extents);
259   }
260 
get_glyph_contour_pointhb_font_t261   inline hb_bool_t get_glyph_contour_point (hb_codepoint_t glyph, unsigned int point_index,
262 					    hb_position_t *x, hb_position_t *y)
263   {
264     *x = *y = 0;
265     return klass->get.f.glyph_contour_point (this, user_data,
266 					     glyph, point_index,
267 					     x, y,
268 					     klass->user_data.glyph_contour_point);
269   }
270 
get_glyph_namehb_font_t271   inline hb_bool_t get_glyph_name (hb_codepoint_t glyph,
272 				   char *name, unsigned int size)
273   {
274     if (size) *name = '\0';
275     return klass->get.f.glyph_name (this, user_data,
276 				    glyph,
277 				    name, size,
278 				    klass->user_data.glyph_name);
279   }
280 
get_glyph_from_namehb_font_t281   inline hb_bool_t get_glyph_from_name (const char *name, int len, /* -1 means nul-terminated */
282 					hb_codepoint_t *glyph)
283   {
284     *glyph = 0;
285     if (len == -1) len = strlen (name);
286     return klass->get.f.glyph_from_name (this, user_data,
287 					 name, len,
288 					 glyph,
289 					 klass->user_data.glyph_from_name);
290   }
291 
292 
293   /* A bit higher-level, and with fallback */
294 
get_extents_for_directionhb_font_t295   inline void get_extents_for_direction (hb_direction_t direction,
296 					 hb_font_extents_t *extents)
297   {
298     if (likely (HB_DIRECTION_IS_HORIZONTAL (direction))) {
299       if (!get_font_h_extents (extents))
300       {
301 	extents->ascender = y_scale * .8;
302 	extents->descender = y_scale - extents->ascender;
303 	extents->line_gap = 0;
304       }
305     } else {
306       if (!get_font_v_extents (extents))
307       {
308 	extents->ascender = x_scale / 2;
309 	extents->descender = x_scale - extents->ascender;
310 	extents->line_gap = 0;
311       }
312     }
313   }
314 
get_glyph_advance_for_directionhb_font_t315   inline void get_glyph_advance_for_direction (hb_codepoint_t glyph,
316 					       hb_direction_t direction,
317 					       hb_position_t *x, hb_position_t *y)
318   {
319     if (likely (HB_DIRECTION_IS_HORIZONTAL (direction))) {
320       *x = get_glyph_h_advance (glyph);
321       *y = 0;
322     } else {
323       *x = 0;
324       *y = get_glyph_v_advance (glyph);
325     }
326   }
327 
328   /* Internal only */
guess_v_origin_minus_h_originhb_font_t329   inline void guess_v_origin_minus_h_origin (hb_codepoint_t glyph,
330 					     hb_position_t *x, hb_position_t *y)
331   {
332     *x = get_glyph_h_advance (glyph) / 2;
333 
334     /* TODO use font_extents.ascender */
335     *y = y_scale;
336   }
337 
get_glyph_origin_for_directionhb_font_t338   inline void get_glyph_origin_for_direction (hb_codepoint_t glyph,
339 					      hb_direction_t direction,
340 					      hb_position_t *x, hb_position_t *y)
341   {
342     if (likely (HB_DIRECTION_IS_HORIZONTAL (direction)))
343     {
344       if (!get_glyph_h_origin (glyph, x, y) &&
345 	   get_glyph_v_origin (glyph, x, y))
346       {
347 	hb_position_t dx, dy;
348 	guess_v_origin_minus_h_origin (glyph, &dx, &dy);
349 	*x -= dx; *y -= dy;
350       }
351     }
352     else
353     {
354       if (!get_glyph_v_origin (glyph, x, y) &&
355 	   get_glyph_h_origin (glyph, x, y))
356       {
357 	hb_position_t dx, dy;
358 	guess_v_origin_minus_h_origin (glyph, &dx, &dy);
359 	*x += dx; *y += dy;
360       }
361     }
362   }
363 
add_glyph_h_originhb_font_t364   inline void add_glyph_h_origin (hb_codepoint_t glyph,
365 				  hb_position_t *x, hb_position_t *y)
366   {
367     hb_position_t origin_x, origin_y;
368 
369     get_glyph_h_origin (glyph, &origin_x, &origin_y);
370 
371     *x += origin_x;
372     *y += origin_y;
373   }
add_glyph_v_originhb_font_t374   inline void add_glyph_v_origin (hb_codepoint_t glyph,
375 				  hb_position_t *x, hb_position_t *y)
376   {
377     hb_position_t origin_x, origin_y;
378 
379     get_glyph_v_origin (glyph, &origin_x, &origin_y);
380 
381     *x += origin_x;
382     *y += origin_y;
383   }
add_glyph_origin_for_directionhb_font_t384   inline void add_glyph_origin_for_direction (hb_codepoint_t glyph,
385 					      hb_direction_t direction,
386 					      hb_position_t *x, hb_position_t *y)
387   {
388     hb_position_t origin_x, origin_y;
389 
390     get_glyph_origin_for_direction (glyph, direction, &origin_x, &origin_y);
391 
392     *x += origin_x;
393     *y += origin_y;
394   }
395 
subtract_glyph_h_originhb_font_t396   inline void subtract_glyph_h_origin (hb_codepoint_t glyph,
397 				       hb_position_t *x, hb_position_t *y)
398   {
399     hb_position_t origin_x, origin_y;
400 
401     get_glyph_h_origin (glyph, &origin_x, &origin_y);
402 
403     *x -= origin_x;
404     *y -= origin_y;
405   }
subtract_glyph_v_originhb_font_t406   inline void subtract_glyph_v_origin (hb_codepoint_t glyph,
407 				       hb_position_t *x, hb_position_t *y)
408   {
409     hb_position_t origin_x, origin_y;
410 
411     get_glyph_v_origin (glyph, &origin_x, &origin_y);
412 
413     *x -= origin_x;
414     *y -= origin_y;
415   }
subtract_glyph_origin_for_directionhb_font_t416   inline void subtract_glyph_origin_for_direction (hb_codepoint_t glyph,
417 						   hb_direction_t direction,
418 						   hb_position_t *x, hb_position_t *y)
419   {
420     hb_position_t origin_x, origin_y;
421 
422     get_glyph_origin_for_direction (glyph, direction, &origin_x, &origin_y);
423 
424     *x -= origin_x;
425     *y -= origin_y;
426   }
427 
get_glyph_kerning_for_directionhb_font_t428   inline void get_glyph_kerning_for_direction (hb_codepoint_t first_glyph, hb_codepoint_t second_glyph,
429 					       hb_direction_t direction,
430 					       hb_position_t *x, hb_position_t *y)
431   {
432     if (likely (HB_DIRECTION_IS_HORIZONTAL (direction))) {
433       *x = get_glyph_h_kerning (first_glyph, second_glyph);
434       *y = 0;
435     } else {
436       *x = 0;
437       *y = get_glyph_v_kerning (first_glyph, second_glyph);
438     }
439   }
440 
get_glyph_extents_for_originhb_font_t441   inline hb_bool_t get_glyph_extents_for_origin (hb_codepoint_t glyph,
442 						 hb_direction_t direction,
443 						 hb_glyph_extents_t *extents)
444   {
445     hb_bool_t ret = get_glyph_extents (glyph, extents);
446 
447     if (ret)
448       subtract_glyph_origin_for_direction (glyph, direction, &extents->x_bearing, &extents->y_bearing);
449 
450     return ret;
451   }
452 
get_glyph_contour_point_for_originhb_font_t453   inline hb_bool_t get_glyph_contour_point_for_origin (hb_codepoint_t glyph, unsigned int point_index,
454 						       hb_direction_t direction,
455 						       hb_position_t *x, hb_position_t *y)
456   {
457     hb_bool_t ret = get_glyph_contour_point (glyph, point_index, x, y);
458 
459     if (ret)
460       subtract_glyph_origin_for_direction (glyph, direction, x, y);
461 
462     return ret;
463   }
464 
465   /* Generates gidDDD if glyph has no name. */
466   inline void
glyph_to_stringhb_font_t467   glyph_to_string (hb_codepoint_t glyph,
468 		   char *s, unsigned int size)
469   {
470     if (get_glyph_name (glyph, s, size)) return;
471 
472     if (size && snprintf (s, size, "gid%u", glyph) < 0)
473       *s = '\0';
474   }
475 
476   /* Parses gidDDD and uniUUUU strings automatically. */
477   inline hb_bool_t
glyph_from_stringhb_font_t478   glyph_from_string (const char *s, int len, /* -1 means nul-terminated */
479 		     hb_codepoint_t *glyph)
480   {
481     if (get_glyph_from_name (s, len, glyph)) return true;
482 
483     if (len == -1) len = strlen (s);
484 
485     /* Straight glyph index. */
486     if (hb_codepoint_parse (s, len, 10, glyph))
487       return true;
488 
489     if (len > 3)
490     {
491       /* gidDDD syntax for glyph indices. */
492       if (0 == strncmp (s, "gid", 3) &&
493 	  hb_codepoint_parse (s + 3, len - 3, 10, glyph))
494 	return true;
495 
496       /* uniUUUU and other Unicode character indices. */
497       hb_codepoint_t unichar;
498       if (0 == strncmp (s, "uni", 3) &&
499 	  hb_codepoint_parse (s + 3, len - 3, 16, &unichar) &&
500 	  get_nominal_glyph (unichar, glyph))
501 	return true;
502     }
503 
504     return false;
505   }
506 
507   private:
em_scalehb_font_t508   inline hb_position_t em_scale (int16_t v, int scale) { return (hb_position_t) (v * (int64_t) scale / face->get_upem ()); }
509 };
510 
511 #define HB_SHAPER_DATA_CREATE_FUNC_EXTRA_ARGS
512 #define HB_SHAPER_IMPLEMENT(shaper) HB_SHAPER_DATA_PROTOTYPE(shaper, font);
513 #include "hb-shaper-list.hh"
514 #undef HB_SHAPER_IMPLEMENT
515 #undef HB_SHAPER_DATA_CREATE_FUNC_EXTRA_ARGS
516 
517 
518 #endif /* HB_FONT_PRIVATE_HH */
519