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 (glyph) \
46   HB_FONT_FUNC_IMPLEMENT (glyph_h_advance) \
47   HB_FONT_FUNC_IMPLEMENT (glyph_v_advance) \
48   HB_FONT_FUNC_IMPLEMENT (glyph_h_origin) \
49   HB_FONT_FUNC_IMPLEMENT (glyph_v_origin) \
50   HB_FONT_FUNC_IMPLEMENT (glyph_h_kerning) \
51   HB_FONT_FUNC_IMPLEMENT (glyph_v_kerning) \
52   HB_FONT_FUNC_IMPLEMENT (glyph_extents) \
53   HB_FONT_FUNC_IMPLEMENT (glyph_contour_point) \
54   HB_FONT_FUNC_IMPLEMENT (glyph_name) \
55   HB_FONT_FUNC_IMPLEMENT (glyph_from_name) \
56   /* ^--- Add new callbacks here */
57 
58 struct hb_font_funcs_t {
59   hb_object_header_t header;
60   ASSERT_POD ();
61 
62   hb_bool_t immutable;
63 
64   /* Don't access these directly.  Call hb_font_get_*() instead. */
65 
66   struct {
67 #define HB_FONT_FUNC_IMPLEMENT(name) hb_font_get_##name##_func_t name;
68     HB_FONT_FUNCS_IMPLEMENT_CALLBACKS
69 #undef HB_FONT_FUNC_IMPLEMENT
70   } get;
71 
72   struct {
73 #define HB_FONT_FUNC_IMPLEMENT(name) void *name;
74     HB_FONT_FUNCS_IMPLEMENT_CALLBACKS
75 #undef HB_FONT_FUNC_IMPLEMENT
76   } user_data;
77 
78   struct {
79 #define HB_FONT_FUNC_IMPLEMENT(name) hb_destroy_func_t name;
80     HB_FONT_FUNCS_IMPLEMENT_CALLBACKS
81 #undef HB_FONT_FUNC_IMPLEMENT
82   } destroy;
83 };
84 
85 
86 
87 /*
88  * hb_font_t
89  */
90 
91 struct hb_font_t {
92   hb_object_header_t header;
93   ASSERT_POD ();
94 
95   hb_bool_t immutable;
96 
97   hb_font_t *parent;
98   hb_face_t *face;
99 
100   int x_scale;
101   int y_scale;
102 
103   unsigned int x_ppem;
104   unsigned int y_ppem;
105 
106   hb_font_funcs_t   *klass;
107   void              *user_data;
108   hb_destroy_func_t  destroy;
109 
110   struct hb_shaper_data_t shaper_data;
111 
112 
113   /* Convert from font-space to user-space */
em_scale_xhb_font_t114   inline hb_position_t em_scale_x (int16_t v) { return em_scale (v, this->x_scale); }
em_scale_yhb_font_t115   inline hb_position_t em_scale_y (int16_t v) { return em_scale (v, this->y_scale); }
116 
117   /* Convert from parent-font user-space to our user-space */
parent_scale_x_distancehb_font_t118   inline hb_position_t parent_scale_x_distance (hb_position_t v) {
119     if (unlikely (parent && parent->x_scale != x_scale))
120       return (hb_position_t) (v * (int64_t) this->x_scale / this->parent->x_scale);
121     return v;
122   }
parent_scale_y_distancehb_font_t123   inline hb_position_t parent_scale_y_distance (hb_position_t v) {
124     if (unlikely (parent && parent->y_scale != y_scale))
125       return (hb_position_t) (v * (int64_t) this->y_scale / this->parent->y_scale);
126     return v;
127   }
parent_scale_x_positionhb_font_t128   inline hb_position_t parent_scale_x_position (hb_position_t v) {
129     return parent_scale_x_distance (v);
130   }
parent_scale_y_positionhb_font_t131   inline hb_position_t parent_scale_y_position (hb_position_t v) {
132     return parent_scale_y_distance (v);
133   }
134 
parent_scale_distancehb_font_t135   inline void parent_scale_distance (hb_position_t *x, hb_position_t *y) {
136     *x = parent_scale_x_distance (*x);
137     *y = parent_scale_y_distance (*y);
138   }
parent_scale_positionhb_font_t139   inline void parent_scale_position (hb_position_t *x, hb_position_t *y) {
140     *x = parent_scale_x_position (*x);
141     *y = parent_scale_y_position (*y);
142   }
143 
144 
145   /* Public getters */
146 
has_glyphhb_font_t147   inline hb_bool_t has_glyph (hb_codepoint_t unicode)
148   {
149     hb_codepoint_t glyph;
150     return get_glyph (unicode, 0, &glyph);
151   }
152 
get_glyphhb_font_t153   inline hb_bool_t get_glyph (hb_codepoint_t unicode, hb_codepoint_t variation_selector,
154 			      hb_codepoint_t *glyph)
155   {
156     *glyph = 0;
157     return klass->get.glyph (this, user_data,
158 			     unicode, variation_selector, glyph,
159 			     klass->user_data.glyph);
160   }
161 
get_glyph_h_advancehb_font_t162   inline hb_position_t get_glyph_h_advance (hb_codepoint_t glyph)
163   {
164     return klass->get.glyph_h_advance (this, user_data,
165 				       glyph,
166 				       klass->user_data.glyph_h_advance);
167   }
168 
get_glyph_v_advancehb_font_t169   inline hb_position_t get_glyph_v_advance (hb_codepoint_t glyph)
170   {
171     return klass->get.glyph_v_advance (this, user_data,
172 				       glyph,
173 				       klass->user_data.glyph_v_advance);
174   }
175 
get_glyph_h_originhb_font_t176   inline hb_bool_t get_glyph_h_origin (hb_codepoint_t glyph,
177 				       hb_position_t *x, hb_position_t *y)
178   {
179     *x = *y = 0;
180     return klass->get.glyph_h_origin (this, user_data,
181 				      glyph, x, y,
182 				      klass->user_data.glyph_h_origin);
183   }
184 
get_glyph_v_originhb_font_t185   inline hb_bool_t get_glyph_v_origin (hb_codepoint_t glyph,
186 				       hb_position_t *x, hb_position_t *y)
187   {
188     *x = *y = 0;
189     return klass->get.glyph_v_origin (this, user_data,
190 				      glyph, x, y,
191 				      klass->user_data.glyph_v_origin);
192   }
193 
get_glyph_h_kerninghb_font_t194   inline hb_position_t get_glyph_h_kerning (hb_codepoint_t left_glyph, hb_codepoint_t right_glyph)
195   {
196     return klass->get.glyph_h_kerning (this, user_data,
197 				       left_glyph, right_glyph,
198 				       klass->user_data.glyph_h_kerning);
199   }
200 
get_glyph_v_kerninghb_font_t201   inline hb_position_t get_glyph_v_kerning (hb_codepoint_t top_glyph, hb_codepoint_t bottom_glyph)
202   {
203     return klass->get.glyph_v_kerning (this, user_data,
204 				       top_glyph, bottom_glyph,
205 				       klass->user_data.glyph_v_kerning);
206   }
207 
get_glyph_extentshb_font_t208   inline hb_bool_t get_glyph_extents (hb_codepoint_t glyph,
209 				      hb_glyph_extents_t *extents)
210   {
211     memset (extents, 0, sizeof (*extents));
212     return klass->get.glyph_extents (this, user_data,
213 				     glyph,
214 				     extents,
215 				     klass->user_data.glyph_extents);
216   }
217 
get_glyph_contour_pointhb_font_t218   inline hb_bool_t get_glyph_contour_point (hb_codepoint_t glyph, unsigned int point_index,
219 					    hb_position_t *x, hb_position_t *y)
220   {
221     *x = *y = 0;
222     return klass->get.glyph_contour_point (this, user_data,
223 					   glyph, point_index,
224 					   x, y,
225 					   klass->user_data.glyph_contour_point);
226   }
227 
get_glyph_namehb_font_t228   inline hb_bool_t get_glyph_name (hb_codepoint_t glyph,
229 				   char *name, unsigned int size)
230   {
231     if (size) *name = '\0';
232     return klass->get.glyph_name (this, user_data,
233 				  glyph,
234 				  name, size,
235 				  klass->user_data.glyph_name);
236   }
237 
get_glyph_from_namehb_font_t238   inline hb_bool_t get_glyph_from_name (const char *name, int len, /* -1 means nul-terminated */
239 					hb_codepoint_t *glyph)
240   {
241     *glyph = 0;
242     if (len == -1) len = strlen (name);
243     return klass->get.glyph_from_name (this, user_data,
244 				       name, len,
245 				       glyph,
246 				       klass->user_data.glyph_from_name);
247   }
248 
249 
250   /* A bit higher-level, and with fallback */
251 
get_glyph_advance_for_directionhb_font_t252   inline void get_glyph_advance_for_direction (hb_codepoint_t glyph,
253 					       hb_direction_t direction,
254 					       hb_position_t *x, hb_position_t *y)
255   {
256     if (likely (HB_DIRECTION_IS_HORIZONTAL (direction))) {
257       *x = get_glyph_h_advance (glyph);
258       *y = 0;
259     } else {
260       *x = 0;
261       *y = get_glyph_v_advance (glyph);
262     }
263   }
264 
265   /* Internal only */
guess_v_origin_minus_h_originhb_font_t266   inline void guess_v_origin_minus_h_origin (hb_codepoint_t glyph,
267 					     hb_position_t *x, hb_position_t *y)
268   {
269     *x = get_glyph_h_advance (glyph) / 2;
270 
271     /* TODO use font_metics.ascent */
272     *y = y_scale;
273   }
274 
get_glyph_origin_for_directionhb_font_t275   inline void get_glyph_origin_for_direction (hb_codepoint_t glyph,
276 					      hb_direction_t direction,
277 					      hb_position_t *x, hb_position_t *y)
278   {
279     if (likely (HB_DIRECTION_IS_HORIZONTAL (direction)))
280     {
281       if (!get_glyph_h_origin (glyph, x, y) &&
282 	   get_glyph_v_origin (glyph, x, y))
283       {
284 	hb_position_t dx, dy;
285 	guess_v_origin_minus_h_origin (glyph, &dx, &dy);
286 	*x -= dx; *y -= dy;
287       }
288     }
289     else
290     {
291       if (!get_glyph_v_origin (glyph, x, y) &&
292 	   get_glyph_h_origin (glyph, x, y))
293       {
294 	hb_position_t dx, dy;
295 	guess_v_origin_minus_h_origin (glyph, &dx, &dy);
296 	*x += dx; *y += dy;
297       }
298     }
299   }
300 
add_glyph_origin_for_directionhb_font_t301   inline void add_glyph_origin_for_direction (hb_codepoint_t glyph,
302 					      hb_direction_t direction,
303 					      hb_position_t *x, hb_position_t *y)
304   {
305     hb_position_t origin_x, origin_y;
306 
307     get_glyph_origin_for_direction (glyph, direction, &origin_x, &origin_y);
308 
309     *x += origin_x;
310     *y += origin_y;
311   }
312 
subtract_glyph_origin_for_directionhb_font_t313   inline void subtract_glyph_origin_for_direction (hb_codepoint_t glyph,
314 						   hb_direction_t direction,
315 						   hb_position_t *x, hb_position_t *y)
316   {
317     hb_position_t origin_x, origin_y;
318 
319     get_glyph_origin_for_direction (glyph, direction, &origin_x, &origin_y);
320 
321     *x -= origin_x;
322     *y -= origin_y;
323   }
324 
get_glyph_kerning_for_directionhb_font_t325   inline void get_glyph_kerning_for_direction (hb_codepoint_t first_glyph, hb_codepoint_t second_glyph,
326 					       hb_direction_t direction,
327 					       hb_position_t *x, hb_position_t *y)
328   {
329     if (likely (HB_DIRECTION_IS_HORIZONTAL (direction))) {
330       *x = get_glyph_h_kerning (first_glyph, second_glyph);
331       *y = 0;
332     } else {
333       *x = 0;
334       *y = get_glyph_v_kerning (first_glyph, second_glyph);
335     }
336   }
337 
get_glyph_extents_for_originhb_font_t338   inline hb_bool_t get_glyph_extents_for_origin (hb_codepoint_t glyph,
339 						 hb_direction_t direction,
340 						 hb_glyph_extents_t *extents)
341   {
342     hb_bool_t ret = get_glyph_extents (glyph, extents);
343 
344     if (ret)
345       subtract_glyph_origin_for_direction (glyph, direction, &extents->x_bearing, &extents->y_bearing);
346 
347     return ret;
348   }
349 
get_glyph_contour_point_for_originhb_font_t350   inline hb_bool_t get_glyph_contour_point_for_origin (hb_codepoint_t glyph, unsigned int point_index,
351 						       hb_direction_t direction,
352 						       hb_position_t *x, hb_position_t *y)
353   {
354     hb_bool_t ret = get_glyph_contour_point (glyph, point_index, x, y);
355 
356     if (ret)
357       subtract_glyph_origin_for_direction (glyph, direction, x, y);
358 
359     return ret;
360   }
361 
362   /* Generates gidDDD if glyph has no name. */
363   inline void
glyph_to_stringhb_font_t364   glyph_to_string (hb_codepoint_t glyph,
365 		   char *s, unsigned int size)
366   {
367     if (get_glyph_name (glyph, s, size)) return;
368 
369     if (size && snprintf (s, size, "gid%u", glyph) < 0)
370       *s = '\0';
371   }
372 
373   /* Parses gidDDD and uniUUUU strings automatically. */
374   inline hb_bool_t
glyph_from_stringhb_font_t375   glyph_from_string (const char *s, int len, /* -1 means nul-terminated */
376 		     hb_codepoint_t *glyph)
377   {
378     if (get_glyph_from_name (s, len, glyph)) return true;
379 
380     if (len == -1) len = strlen (s);
381 
382     /* Straight glyph index. */
383     if (hb_codepoint_parse (s, len, 10, glyph))
384       return true;
385 
386     if (len > 3)
387     {
388       /* gidDDD syntax for glyph indices. */
389       if (0 == strncmp (s, "gid", 3) &&
390 	  hb_codepoint_parse (s + 3, len - 3, 10, glyph))
391 	return true;
392 
393       /* uniUUUU and other Unicode character indices. */
394       hb_codepoint_t unichar;
395       if (0 == strncmp (s, "uni", 3) &&
396 	  hb_codepoint_parse (s + 3, len - 3, 16, &unichar) &&
397 	  get_glyph (unichar, 0, glyph))
398 	return true;
399     }
400 
401     return false;
402   }
403 
404   private:
em_scalehb_font_t405   inline hb_position_t em_scale (int16_t v, int scale) { return (hb_position_t) (v * (int64_t) scale / face->get_upem ()); }
406 };
407 
408 #define HB_SHAPER_DATA_CREATE_FUNC_EXTRA_ARGS
409 #define HB_SHAPER_IMPLEMENT(shaper) HB_SHAPER_DATA_PROTOTYPE(shaper, font);
410 #include "hb-shaper-list.hh"
411 #undef HB_SHAPER_IMPLEMENT
412 #undef HB_SHAPER_DATA_CREATE_FUNC_EXTRA_ARGS
413 
414 
415 #endif /* HB_FONT_PRIVATE_HH */
416