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comparison mupdf-source/thirdparty/harfbuzz/src/hb-ot-metrics.cc @ 2:b50eed0cc0ef upstream

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ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. The directory name has changed: no version number in the expanded directory now.
author Franz Glasner <fzglas.hg@dom66.de>
date Mon, 15 Sep 2025 11:43:07 +0200
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1:1d09e1dec1d9 2:b50eed0cc0ef
1 /*
2 * Copyright © 2018-2019 Ebrahim Byagowi
3 *
4 * This is part of HarfBuzz, a text shaping library.
5 *
6 * Permission is hereby granted, without written agreement and without
7 * license or royalty fees, to use, copy, modify, and distribute this
8 * software and its documentation for any purpose, provided that the
9 * above copyright notice and the following two paragraphs appear in
10 * all copies of this software.
11 *
12 * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
13 * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
14 * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
15 * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
16 * DAMAGE.
17 *
18 * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
19 * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
20 * FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
21 * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
22 * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
23 */
24
25 #include "hb.hh"
26
27 #include "hb-ot-var-mvar-table.hh"
28 #include "hb-ot-gasp-table.hh" // Just so we compile it; unused otherwise.
29 #include "hb-ot-os2-table.hh"
30 #include "hb-ot-post-table.hh"
31 #include "hb-ot-hhea-table.hh"
32 #include "hb-ot-metrics.hh"
33 #include "hb-ot-face.hh"
34
35
36 /**
37 * SECTION:hb-ot-metrics
38 * @title: hb-ot-metrics
39 * @short_description: OpenType Metrics
40 * @include: hb-ot.h
41 *
42 * Functions for fetching metrics from fonts.
43 **/
44
45 static float
46 _fix_ascender_descender (float value, hb_ot_metrics_tag_t metrics_tag)
47 {
48 if (metrics_tag == HB_OT_METRICS_TAG_HORIZONTAL_ASCENDER ||
49 metrics_tag == HB_OT_METRICS_TAG_VERTICAL_ASCENDER)
50 return fabs ((double) value);
51 if (metrics_tag == HB_OT_METRICS_TAG_HORIZONTAL_DESCENDER ||
52 metrics_tag == HB_OT_METRICS_TAG_VERTICAL_DESCENDER)
53 return -fabs ((double) value);
54 return value;
55 }
56
57 /* The common part of _get_position logic needed on hb-ot-font and here
58 to be able to have slim builds without the not always needed parts */
59 bool
60 _hb_ot_metrics_get_position_common (hb_font_t *font,
61 hb_ot_metrics_tag_t metrics_tag,
62 hb_position_t *position /* OUT. May be NULL. */)
63 {
64 hb_face_t *face = font->face;
65 switch ((unsigned) metrics_tag)
66 {
67 #ifndef HB_NO_VAR
68 #define GET_VAR face->table.MVAR->get_var (metrics_tag, font->coords, font->num_coords)
69 #else
70 #define GET_VAR .0f
71 #endif
72 #define GET_METRIC_X(TABLE, ATTR) \
73 (face->table.TABLE->has_data () && \
74 ((void) (position && (*position = font->em_scalef_x (_fix_ascender_descender ( \
75 face->table.TABLE->ATTR + GET_VAR, metrics_tag)))), true))
76 #define GET_METRIC_Y(TABLE, ATTR) \
77 (face->table.TABLE->has_data () && \
78 ((void) (position && (*position = font->em_scalef_y (_fix_ascender_descender ( \
79 face->table.TABLE->ATTR + GET_VAR, metrics_tag)))), true))
80
81 case HB_OT_METRICS_TAG_HORIZONTAL_ASCENDER:
82 return (face->table.OS2->use_typo_metrics () && GET_METRIC_Y (OS2, sTypoAscender)) ||
83 GET_METRIC_Y (hhea, ascender);
84 case HB_OT_METRICS_TAG_HORIZONTAL_DESCENDER:
85 return (face->table.OS2->use_typo_metrics () && GET_METRIC_Y (OS2, sTypoDescender)) ||
86 GET_METRIC_Y (hhea, descender);
87 case HB_OT_METRICS_TAG_HORIZONTAL_LINE_GAP:
88 return (face->table.OS2->use_typo_metrics () && GET_METRIC_Y (OS2, sTypoLineGap)) ||
89 GET_METRIC_Y (hhea, lineGap);
90
91 #ifndef HB_NO_VERTICAL
92 case HB_OT_METRICS_TAG_VERTICAL_ASCENDER: return GET_METRIC_X (vhea, ascender);
93 case HB_OT_METRICS_TAG_VERTICAL_DESCENDER: return GET_METRIC_X (vhea, descender);
94 case HB_OT_METRICS_TAG_VERTICAL_LINE_GAP: return GET_METRIC_X (vhea, lineGap);
95 #endif
96
97 #undef GET_METRIC_Y
98 #undef GET_METRIC_X
99 #undef GET_VAR
100 default: assert (0); return false;
101 }
102 }
103
104 #ifndef HB_NO_METRICS
105
106 #if 0
107 static bool
108 _get_gasp (hb_face_t *face, float *result, hb_ot_metrics_tag_t metrics_tag)
109 {
110 const OT::GaspRange& range = face->table.gasp->get_gasp_range (metrics_tag - HB_TAG ('g','s','p','0'));
111 if (&range == &Null (OT::GaspRange)) return false;
112 if (result) *result = range.rangeMaxPPEM + font->face->table.MVAR->get_var (metrics_tag, font->coords, font->num_coords);
113 return true;
114 }
115 #endif
116
117 /* Private tags for https://github.com/harfbuzz/harfbuzz/issues/1866 */
118 #define _HB_OT_METRICS_TAG_HORIZONTAL_ASCENDER_OS2 HB_TAG ('O','a','s','c')
119 #define _HB_OT_METRICS_TAG_HORIZONTAL_ASCENDER_HHEA HB_TAG ('H','a','s','c')
120 #define _HB_OT_METRICS_TAG_HORIZONTAL_DESCENDER_OS2 HB_TAG ('O','d','s','c')
121 #define _HB_OT_METRICS_TAG_HORIZONTAL_DESCENDER_HHEA HB_TAG ('H','d','s','c')
122 #define _HB_OT_METRICS_TAG_HORIZONTAL_LINE_GAP_OS2 HB_TAG ('O','l','g','p')
123 #define _HB_OT_METRICS_TAG_HORIZONTAL_LINE_GAP_HHEA HB_TAG ('H','l','g','p')
124
125 /**
126 * hb_ot_metrics_get_position:
127 * @font: an #hb_font_t object.
128 * @metrics_tag: tag of metrics value you like to fetch.
129 * @position: (out) (optional): result of metrics value from the font.
130 *
131 * Fetches metrics value corresponding to @metrics_tag from @font.
132 *
133 * Returns: Whether found the requested metrics in the font.
134 * Since: 2.6.0
135 **/
136 hb_bool_t
137 hb_ot_metrics_get_position (hb_font_t *font,
138 hb_ot_metrics_tag_t metrics_tag,
139 hb_position_t *position /* OUT. May be NULL. */)
140 {
141 hb_face_t *face = font->face;
142 switch ((unsigned) metrics_tag)
143 {
144 case HB_OT_METRICS_TAG_HORIZONTAL_ASCENDER:
145 case HB_OT_METRICS_TAG_HORIZONTAL_DESCENDER:
146 case HB_OT_METRICS_TAG_HORIZONTAL_LINE_GAP:
147 case HB_OT_METRICS_TAG_VERTICAL_ASCENDER:
148 case HB_OT_METRICS_TAG_VERTICAL_DESCENDER:
149 case HB_OT_METRICS_TAG_VERTICAL_LINE_GAP: return _hb_ot_metrics_get_position_common (font, metrics_tag, position);
150 #ifndef HB_NO_VAR
151 #define GET_VAR hb_ot_metrics_get_variation (font, metrics_tag)
152 #else
153 #define GET_VAR 0
154 #endif
155 #define GET_METRIC_X(TABLE, ATTR) \
156 (face->table.TABLE->has_data () && \
157 ((void) (position && (*position = font->em_scalef_x (face->table.TABLE->ATTR + GET_VAR))), true))
158 #define GET_METRIC_Y(TABLE, ATTR) \
159 (face->table.TABLE->has_data () && \
160 ((void) (position && (*position = font->em_scalef_y (face->table.TABLE->ATTR + GET_VAR))), true))
161 case HB_OT_METRICS_TAG_HORIZONTAL_CLIPPING_ASCENT: return GET_METRIC_Y (OS2, usWinAscent);
162 case HB_OT_METRICS_TAG_HORIZONTAL_CLIPPING_DESCENT: return GET_METRIC_Y (OS2, usWinDescent);
163
164 case HB_OT_METRICS_TAG_HORIZONTAL_CARET_RISE:
165 case HB_OT_METRICS_TAG_HORIZONTAL_CARET_RUN:
166 {
167 unsigned mult = 1u;
168
169 if (font->slant)
170 {
171 unsigned rise = face->table.hhea->caretSlopeRise;
172 unsigned upem = face->get_upem ();
173 mult = (rise && rise < upem) ? hb_min (upem / rise, 256u) : 1u;
174 }
175
176 if (metrics_tag == HB_OT_METRICS_TAG_HORIZONTAL_CARET_RISE)
177 {
178 bool ret = GET_METRIC_Y (hhea, caretSlopeRise);
179
180 if (position)
181 *position *= mult;
182
183 return ret;
184 }
185 else
186 {
187 hb_position_t rise = 0;
188
189 if (font->slant && position && GET_METRIC_Y (hhea, caretSlopeRise))
190 rise = *position;
191
192 bool ret = GET_METRIC_X (hhea, caretSlopeRun);
193
194 if (position)
195 {
196 *position *= mult;
197
198 if (font->slant)
199 *position += _hb_roundf (mult * font->slant_xy * rise);
200 }
201
202 return ret;
203 }
204 }
205 case HB_OT_METRICS_TAG_HORIZONTAL_CARET_OFFSET: return GET_METRIC_X (hhea, caretOffset);
206
207 #ifndef HB_NO_VERTICAL
208 case HB_OT_METRICS_TAG_VERTICAL_CARET_RISE: return GET_METRIC_X (vhea, caretSlopeRise);
209 case HB_OT_METRICS_TAG_VERTICAL_CARET_RUN: return GET_METRIC_Y (vhea, caretSlopeRun);
210 case HB_OT_METRICS_TAG_VERTICAL_CARET_OFFSET: return GET_METRIC_Y (vhea, caretOffset);
211 #endif
212 case HB_OT_METRICS_TAG_X_HEIGHT: return GET_METRIC_Y (OS2->v2 (), sxHeight);
213 case HB_OT_METRICS_TAG_CAP_HEIGHT: return GET_METRIC_Y (OS2->v2 (), sCapHeight);
214 case HB_OT_METRICS_TAG_SUBSCRIPT_EM_X_SIZE: return GET_METRIC_X (OS2, ySubscriptXSize);
215 case HB_OT_METRICS_TAG_SUBSCRIPT_EM_Y_SIZE: return GET_METRIC_Y (OS2, ySubscriptYSize);
216 case HB_OT_METRICS_TAG_SUBSCRIPT_EM_X_OFFSET: return GET_METRIC_X (OS2, ySubscriptXOffset);
217 case HB_OT_METRICS_TAG_SUBSCRIPT_EM_Y_OFFSET: return GET_METRIC_Y (OS2, ySubscriptYOffset);
218 case HB_OT_METRICS_TAG_SUPERSCRIPT_EM_X_SIZE: return GET_METRIC_X (OS2, ySuperscriptXSize);
219 case HB_OT_METRICS_TAG_SUPERSCRIPT_EM_Y_SIZE: return GET_METRIC_Y (OS2, ySuperscriptYSize);
220 case HB_OT_METRICS_TAG_SUPERSCRIPT_EM_X_OFFSET: return GET_METRIC_X (OS2, ySuperscriptXOffset);
221 case HB_OT_METRICS_TAG_SUPERSCRIPT_EM_Y_OFFSET: return GET_METRIC_Y (OS2, ySuperscriptYOffset);
222 case HB_OT_METRICS_TAG_STRIKEOUT_SIZE: return GET_METRIC_Y (OS2, yStrikeoutSize);
223 case HB_OT_METRICS_TAG_STRIKEOUT_OFFSET: return GET_METRIC_Y (OS2, yStrikeoutPosition);
224 case HB_OT_METRICS_TAG_UNDERLINE_SIZE: return GET_METRIC_Y (post->table, underlineThickness);
225 case HB_OT_METRICS_TAG_UNDERLINE_OFFSET: return GET_METRIC_Y (post->table, underlinePosition);
226
227 /* Private tags */
228 case _HB_OT_METRICS_TAG_HORIZONTAL_ASCENDER_OS2: return GET_METRIC_Y (OS2, sTypoAscender);
229 case _HB_OT_METRICS_TAG_HORIZONTAL_ASCENDER_HHEA: return GET_METRIC_Y (hhea, ascender);
230 case _HB_OT_METRICS_TAG_HORIZONTAL_DESCENDER_OS2: return GET_METRIC_Y (OS2, sTypoDescender);
231 case _HB_OT_METRICS_TAG_HORIZONTAL_DESCENDER_HHEA: return GET_METRIC_Y (hhea, descender);
232 case _HB_OT_METRICS_TAG_HORIZONTAL_LINE_GAP_OS2: return GET_METRIC_Y (OS2, sTypoLineGap);
233 case _HB_OT_METRICS_TAG_HORIZONTAL_LINE_GAP_HHEA: return GET_METRIC_Y (hhea, lineGap);
234 #undef GET_METRIC_Y
235 #undef GET_METRIC_X
236 #undef GET_VAR
237 default: return false;
238 }
239 }
240
241 /**
242 * hb_ot_metrics_get_position_with_fallback:
243 * @font: an #hb_font_t object.
244 * @metrics_tag: tag of metrics value you like to fetch.
245 * @position: (out) (optional): result of metrics value from the font.
246 *
247 * Fetches metrics value corresponding to @metrics_tag from @font,
248 * and synthesizes a value if it the value is missing in the font.
249 *
250 * Since: 4.0.0
251 **/
252 void
253 hb_ot_metrics_get_position_with_fallback (hb_font_t *font,
254 hb_ot_metrics_tag_t metrics_tag,
255 hb_position_t *position /* OUT */)
256 {
257 hb_font_extents_t font_extents;
258 hb_codepoint_t glyph;
259 hb_glyph_extents_t extents;
260
261 if (hb_ot_metrics_get_position (font, metrics_tag, position))
262 {
263 if ((metrics_tag != HB_OT_METRICS_TAG_STRIKEOUT_SIZE &&
264 metrics_tag != HB_OT_METRICS_TAG_UNDERLINE_SIZE) ||
265 *position != 0)
266 return;
267 }
268
269 switch (metrics_tag)
270 {
271 case HB_OT_METRICS_TAG_HORIZONTAL_ASCENDER:
272 case HB_OT_METRICS_TAG_HORIZONTAL_CLIPPING_ASCENT:
273 hb_font_get_extents_for_direction (font, HB_DIRECTION_LTR, &font_extents);
274 *position = font_extents.ascender;
275 break;
276
277 case HB_OT_METRICS_TAG_VERTICAL_ASCENDER:
278 hb_font_get_extents_for_direction (font, HB_DIRECTION_TTB, &font_extents);
279 *position = font_extents.ascender;
280 break;
281
282 case HB_OT_METRICS_TAG_HORIZONTAL_DESCENDER:
283 case HB_OT_METRICS_TAG_HORIZONTAL_CLIPPING_DESCENT:
284 hb_font_get_extents_for_direction (font, HB_DIRECTION_LTR, &font_extents);
285 *position = font_extents.descender;
286 break;
287
288 case HB_OT_METRICS_TAG_VERTICAL_DESCENDER:
289 hb_font_get_extents_for_direction (font, HB_DIRECTION_TTB, &font_extents);
290 *position = font_extents.ascender;
291 break;
292
293 case HB_OT_METRICS_TAG_HORIZONTAL_LINE_GAP:
294 hb_font_get_extents_for_direction (font, HB_DIRECTION_LTR, &font_extents);
295 *position = font_extents.line_gap;
296 break;
297
298 case HB_OT_METRICS_TAG_VERTICAL_LINE_GAP:
299 hb_font_get_extents_for_direction (font, HB_DIRECTION_TTB, &font_extents);
300 *position = font_extents.line_gap;
301 break;
302
303 case HB_OT_METRICS_TAG_HORIZONTAL_CARET_RISE:
304 case HB_OT_METRICS_TAG_VERTICAL_CARET_RISE:
305 *position = 1;
306 break;
307
308 case HB_OT_METRICS_TAG_HORIZONTAL_CARET_RUN:
309 case HB_OT_METRICS_TAG_VERTICAL_CARET_RUN:
310 *position = 0;
311 break;
312
313 case HB_OT_METRICS_TAG_HORIZONTAL_CARET_OFFSET:
314 case HB_OT_METRICS_TAG_VERTICAL_CARET_OFFSET:
315 *position = 0;
316 break;
317
318 case HB_OT_METRICS_TAG_X_HEIGHT:
319 if (hb_font_get_nominal_glyph (font, 'x', &glyph) &&
320 hb_font_get_glyph_extents (font, glyph, &extents))
321 *position = extents.y_bearing;
322 else
323 *position = font->y_scale / 2;
324 break;
325
326 case HB_OT_METRICS_TAG_CAP_HEIGHT:
327 if (hb_font_get_nominal_glyph (font, 'O', &glyph) &&
328 hb_font_get_glyph_extents (font, glyph, &extents))
329 *position = extents.height + 2 * extents.y_bearing;
330 else
331 *position = font->y_scale * 2 / 3;
332 break;
333
334 case HB_OT_METRICS_TAG_STRIKEOUT_SIZE:
335 case HB_OT_METRICS_TAG_UNDERLINE_SIZE:
336 *position = font->y_scale / 18;
337 break;
338
339 case HB_OT_METRICS_TAG_STRIKEOUT_OFFSET:
340 {
341 hb_position_t ascender;
342 hb_ot_metrics_get_position_with_fallback (font,
343 HB_OT_METRICS_TAG_HORIZONTAL_ASCENDER,
344 &ascender);
345 *position = ascender / 2;
346 }
347 break;
348
349 case HB_OT_METRICS_TAG_UNDERLINE_OFFSET:
350 *position = - font->y_scale / 18;
351 break;
352
353 case HB_OT_METRICS_TAG_SUBSCRIPT_EM_X_SIZE:
354 case HB_OT_METRICS_TAG_SUPERSCRIPT_EM_X_SIZE:
355 *position = font->x_scale * 10 / 12;
356 break;
357
358 case HB_OT_METRICS_TAG_SUBSCRIPT_EM_Y_SIZE:
359 case HB_OT_METRICS_TAG_SUPERSCRIPT_EM_Y_SIZE:
360 *position = font->y_scale * 10 / 12;
361 break;
362
363 case HB_OT_METRICS_TAG_SUBSCRIPT_EM_X_OFFSET:
364 case HB_OT_METRICS_TAG_SUPERSCRIPT_EM_X_OFFSET:
365 *position = 0;
366 break;
367
368 case HB_OT_METRICS_TAG_SUBSCRIPT_EM_Y_OFFSET:
369 case HB_OT_METRICS_TAG_SUPERSCRIPT_EM_Y_OFFSET:
370 *position = font->y_scale / 5;
371 break;
372
373 case _HB_OT_METRICS_TAG_MAX_VALUE:
374 default:
375 *position = 0;
376 break;
377 }
378 }
379
380 #ifndef HB_NO_VAR
381 /**
382 * hb_ot_metrics_get_variation:
383 * @font: an #hb_font_t object.
384 * @metrics_tag: tag of metrics value you like to fetch.
385 *
386 * Fetches metrics value corresponding to @metrics_tag from @font with the
387 * current font variation settings applied.
388 *
389 * Returns: The requested metric value.
390 *
391 * Since: 2.6.0
392 **/
393 float
394 hb_ot_metrics_get_variation (hb_font_t *font, hb_ot_metrics_tag_t metrics_tag)
395 {
396 return font->face->table.MVAR->get_var (metrics_tag, font->coords, font->num_coords);
397 }
398
399 /**
400 * hb_ot_metrics_get_x_variation:
401 * @font: an #hb_font_t object.
402 * @metrics_tag: tag of metrics value you like to fetch.
403 *
404 * Fetches horizontal metrics value corresponding to @metrics_tag from @font
405 * with the current font variation settings applied.
406 *
407 * Returns: The requested metric value.
408 *
409 * Since: 2.6.0
410 **/
411 hb_position_t
412 hb_ot_metrics_get_x_variation (hb_font_t *font, hb_ot_metrics_tag_t metrics_tag)
413 {
414 return font->em_scalef_x (hb_ot_metrics_get_variation (font, metrics_tag));
415 }
416
417 /**
418 * hb_ot_metrics_get_y_variation:
419 * @font: an #hb_font_t object.
420 * @metrics_tag: tag of metrics value you like to fetch.
421 *
422 * Fetches vertical metrics value corresponding to @metrics_tag from @font with
423 * the current font variation settings applied.
424 *
425 * Returns: The requested metric value.
426 *
427 * Since: 2.6.0
428 **/
429 hb_position_t
430 hb_ot_metrics_get_y_variation (hb_font_t *font, hb_ot_metrics_tag_t metrics_tag)
431 {
432 return font->em_scalef_y (hb_ot_metrics_get_variation (font, metrics_tag));
433 }
434 #endif
435
436 #endif