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comparison mupdf-source/thirdparty/harfbuzz/src/hb-ot-hmtx-table.hh @ 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 © 2011,2012 Google, Inc.
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 * Google Author(s): Behdad Esfahbod, Roderick Sheeter
25 */
26
27 #ifndef HB_OT_HMTX_TABLE_HH
28 #define HB_OT_HMTX_TABLE_HH
29
30 #include "hb-open-type.hh"
31 #include "hb-ot-maxp-table.hh"
32 #include "hb-ot-hhea-table.hh"
33 #include "hb-ot-var-hvar-table.hh"
34 #include "hb-ot-metrics.hh"
35
36 /*
37 * hmtx -- Horizontal Metrics
38 * https://docs.microsoft.com/en-us/typography/opentype/spec/hmtx
39 * vmtx -- Vertical Metrics
40 * https://docs.microsoft.com/en-us/typography/opentype/spec/vmtx
41 */
42 #define HB_OT_TAG_hmtx HB_TAG('h','m','t','x')
43 #define HB_OT_TAG_vmtx HB_TAG('v','m','t','x')
44
45
46 HB_INTERNAL bool
47 _glyf_get_leading_bearing_with_var_unscaled (hb_font_t *font, hb_codepoint_t glyph, bool is_vertical, int *lsb);
48
49 HB_INTERNAL unsigned
50 _glyf_get_advance_with_var_unscaled (hb_font_t *font, hb_codepoint_t glyph, bool is_vertical);
51
52
53 namespace OT {
54
55
56 struct LongMetric
57 {
58 UFWORD advance; /* Advance width/height. */
59 FWORD sb; /* Leading (left/top) side bearing. */
60 public:
61 DEFINE_SIZE_STATIC (4);
62 };
63
64
65 template <typename T/*Data table type*/, typename H/*Header table type*/, typename V/*Var table type*/>
66 struct hmtxvmtx
67 {
68 bool sanitize (hb_sanitize_context_t *c HB_UNUSED) const
69 {
70 TRACE_SANITIZE (this);
71 /* We don't check for anything specific here. The users of the
72 * struct do all the hard work... */
73 return_trace (true);
74 }
75
76 const hb_hashmap_t<unsigned, hb_pair_t<unsigned, int>>* get_mtx_map (const hb_subset_plan_t *plan) const
77 { return T::is_horizontal ? plan->hmtx_map : plan->vmtx_map; }
78
79 bool subset_update_header (hb_subset_plan_t *plan,
80 unsigned int num_hmetrics) const
81 {
82 hb_blob_t *src_blob = hb_sanitize_context_t ().reference_table<H> (plan->source, H::tableTag);
83 hb_blob_t *dest_blob = hb_blob_copy_writable_or_fail (src_blob);
84 hb_blob_destroy (src_blob);
85
86 if (unlikely (!dest_blob)) {
87 return false;
88 }
89
90 unsigned int length;
91 H *table = (H *) hb_blob_get_data (dest_blob, &length);
92 table->numberOfLongMetrics = num_hmetrics;
93
94 bool result = plan->add_table (H::tableTag, dest_blob);
95 hb_blob_destroy (dest_blob);
96
97 return result;
98 }
99
100 template<typename Iterator,
101 hb_requires (hb_is_iterator (Iterator))>
102 void serialize (hb_serialize_context_t *c,
103 Iterator it,
104 unsigned num_long_metrics)
105 {
106 unsigned idx = 0;
107 for (auto _ : it)
108 {
109 if (idx < num_long_metrics)
110 {
111 LongMetric lm;
112 lm.advance = _.first;
113 lm.sb = _.second;
114 if (unlikely (!c->embed<LongMetric> (&lm))) return;
115 }
116 else
117 {
118 FWORD *sb = c->allocate_size<FWORD> (FWORD::static_size);
119 if (unlikely (!sb)) return;
120 *sb = _.second;
121 }
122 idx++;
123 }
124 }
125
126 bool subset (hb_subset_context_t *c) const
127 {
128 TRACE_SUBSET (this);
129
130 T *table_prime = c->serializer->start_embed <T> ();
131 if (unlikely (!table_prime)) return_trace (false);
132
133 accelerator_t _mtx (c->plan->source);
134 unsigned num_long_metrics;
135 const hb_hashmap_t<unsigned, hb_pair_t<unsigned, int>> *mtx_map = get_mtx_map (c->plan);
136 {
137 /* Determine num_long_metrics to encode. */
138 auto& plan = c->plan;
139
140 num_long_metrics = plan->num_output_glyphs ();
141 unsigned int last_advance = get_new_gid_advance_unscaled (plan, mtx_map, num_long_metrics - 1, _mtx);
142 while (num_long_metrics > 1 &&
143 last_advance == get_new_gid_advance_unscaled (plan, mtx_map, num_long_metrics - 2, _mtx))
144 {
145 num_long_metrics--;
146 }
147 }
148
149 auto it =
150 + hb_range (c->plan->num_output_glyphs ())
151 | hb_map ([c, &_mtx, mtx_map] (unsigned _)
152 {
153 if (!mtx_map->has (_))
154 {
155 hb_codepoint_t old_gid;
156 if (!c->plan->old_gid_for_new_gid (_, &old_gid))
157 return hb_pair (0u, 0);
158 int lsb = 0;
159 (void) _mtx.get_leading_bearing_without_var_unscaled (old_gid, &lsb);
160 return hb_pair (_mtx.get_advance_without_var_unscaled (old_gid), +lsb);
161 }
162 return mtx_map->get (_);
163 })
164 ;
165
166 table_prime->serialize (c->serializer, it, num_long_metrics);
167
168 if (unlikely (c->serializer->in_error ()))
169 return_trace (false);
170
171 // Amend header num hmetrics
172 if (unlikely (!subset_update_header (c->plan, num_long_metrics)))
173 return_trace (false);
174
175 return_trace (true);
176 }
177
178 struct accelerator_t
179 {
180 friend struct hmtxvmtx;
181
182 accelerator_t (hb_face_t *face)
183 {
184 table = hb_sanitize_context_t ().reference_table<hmtxvmtx> (face, T::tableTag);
185 var_table = hb_sanitize_context_t ().reference_table<V> (face, T::variationsTag);
186
187 default_advance = T::is_horizontal ? hb_face_get_upem (face) / 2 : hb_face_get_upem (face);
188
189 /* Populate count variables and sort them out as we go */
190
191 unsigned int len = table.get_length ();
192 if (len & 1)
193 len--;
194
195 num_long_metrics = T::is_horizontal ?
196 face->table.hhea->numberOfLongMetrics :
197 #ifndef HB_NO_VERTICAL
198 face->table.vhea->numberOfLongMetrics
199 #else
200 0
201 #endif
202 ;
203 if (unlikely (num_long_metrics * 4 > len))
204 num_long_metrics = len / 4;
205 len -= num_long_metrics * 4;
206
207 num_bearings = face->table.maxp->get_num_glyphs ();
208
209 if (unlikely (num_bearings < num_long_metrics))
210 num_bearings = num_long_metrics;
211 if (unlikely ((num_bearings - num_long_metrics) * 2 > len))
212 num_bearings = num_long_metrics + len / 2;
213 len -= (num_bearings - num_long_metrics) * 2;
214
215 /* We MUST set num_bearings to zero if num_long_metrics is zero.
216 * Our get_advance() depends on that. */
217 if (unlikely (!num_long_metrics))
218 num_bearings = num_long_metrics = 0;
219
220 num_advances = num_bearings + len / 2;
221 num_glyphs = face->get_num_glyphs ();
222 if (num_glyphs < num_advances)
223 num_glyphs = num_advances;
224 }
225 ~accelerator_t ()
226 {
227 table.destroy ();
228 var_table.destroy ();
229 }
230
231 bool has_data () const { return (bool) num_bearings; }
232
233 bool get_leading_bearing_without_var_unscaled (hb_codepoint_t glyph,
234 int *lsb) const
235 {
236 if (glyph < num_long_metrics)
237 {
238 *lsb = table->longMetricZ[glyph].sb;
239 return true;
240 }
241
242 if (unlikely (glyph >= num_bearings))
243 return false;
244
245 const FWORD *bearings = (const FWORD *) &table->longMetricZ[num_long_metrics];
246 *lsb = bearings[glyph - num_long_metrics];
247 return true;
248 }
249
250 bool get_leading_bearing_with_var_unscaled (hb_font_t *font,
251 hb_codepoint_t glyph,
252 int *lsb) const
253 {
254 if (!font->num_coords)
255 return get_leading_bearing_without_var_unscaled (glyph, lsb);
256
257 #ifndef HB_NO_VAR
258 float delta;
259 if (var_table->get_lsb_delta_unscaled (glyph, font->coords, font->num_coords, &delta) &&
260 get_leading_bearing_without_var_unscaled (glyph, lsb))
261 {
262 *lsb += roundf (delta);
263 return true;
264 }
265
266 return _glyf_get_leading_bearing_with_var_unscaled (font, glyph, T::tableTag == HB_OT_TAG_vmtx, lsb);
267 #else
268 return false;
269 #endif
270 }
271
272 unsigned int get_advance_without_var_unscaled (hb_codepoint_t glyph) const
273 {
274 /* OpenType case. */
275 if (glyph < num_bearings)
276 return table->longMetricZ[hb_min (glyph, (uint32_t) num_long_metrics - 1)].advance;
277
278 /* If num_advances is zero, it means we don't have the metrics table
279 * for this direction: return default advance. Otherwise, there's a
280 * well-defined answer. */
281 if (unlikely (!num_advances))
282 return default_advance;
283
284 #ifdef HB_NO_BEYOND_64K
285 return 0;
286 #endif
287
288 if (unlikely (glyph >= num_glyphs))
289 return 0;
290
291 /* num_bearings <= glyph < num_glyphs;
292 * num_bearings <= num_advances */
293
294 /* TODO Optimize */
295
296 if (num_bearings == num_advances)
297 return get_advance_without_var_unscaled (num_bearings - 1);
298
299 const FWORD *bearings = (const FWORD *) &table->longMetricZ[num_long_metrics];
300 const UFWORD *advances = (const UFWORD *) &bearings[num_bearings - num_long_metrics];
301
302 return advances[hb_min (glyph - num_bearings, num_advances - num_bearings - 1)];
303 }
304
305 unsigned get_advance_with_var_unscaled (hb_codepoint_t glyph,
306 hb_font_t *font,
307 VariationStore::cache_t *store_cache = nullptr) const
308 {
309 unsigned int advance = get_advance_without_var_unscaled (glyph);
310
311 #ifndef HB_NO_VAR
312 if (unlikely (glyph >= num_bearings) || !font->num_coords)
313 return advance;
314
315 if (var_table.get_length ())
316 return advance + roundf (var_table->get_advance_delta_unscaled (glyph,
317 font->coords, font->num_coords,
318 store_cache)); // TODO Optimize?!
319
320 return _glyf_get_advance_with_var_unscaled (font, glyph, T::tableTag == HB_OT_TAG_vmtx);
321 #else
322 return advance;
323 #endif
324 }
325
326 protected:
327 // 0 <= num_long_metrics <= num_bearings <= num_advances <= num_glyphs
328 unsigned num_long_metrics;
329 unsigned num_bearings;
330 unsigned num_advances;
331 unsigned num_glyphs;
332
333 unsigned int default_advance;
334
335 public:
336 hb_blob_ptr_t<hmtxvmtx> table;
337 hb_blob_ptr_t<V> var_table;
338 };
339
340 /* get advance: when no variations, call get_advance_without_var_unscaled.
341 * when there're variations, get advance value from mtx_map in subset_plan*/
342 unsigned get_new_gid_advance_unscaled (const hb_subset_plan_t *plan,
343 const hb_hashmap_t<unsigned, hb_pair_t<unsigned, int>> *mtx_map,
344 unsigned new_gid,
345 const accelerator_t &_mtx) const
346 {
347 if (mtx_map->is_empty () ||
348 (new_gid == 0 && !mtx_map->has (new_gid)))
349 {
350 hb_codepoint_t old_gid = 0;
351 return plan->old_gid_for_new_gid (new_gid, &old_gid) ?
352 _mtx.get_advance_without_var_unscaled (old_gid) : 0;
353 }
354 else
355 { return mtx_map->get (new_gid).first; }
356 }
357
358 protected:
359 UnsizedArrayOf<LongMetric>
360 longMetricZ; /* Paired advance width and leading
361 * bearing values for each glyph. The
362 * value numOfHMetrics comes from
363 * the 'hhea' table. If the font is
364 * monospaced, only one entry need
365 * be in the array, but that entry is
366 * required. The last entry applies to
367 * all subsequent glyphs. */
368 /*UnsizedArrayOf<FWORD> leadingBearingX;*/
369 /* Here the advance is assumed
370 * to be the same as the advance
371 * for the last entry above. The
372 * number of entries in this array is
373 * derived from numGlyphs (from 'maxp'
374 * table) minus numberOfLongMetrics.
375 * This generally is used with a run
376 * of monospaced glyphs (e.g., Kanji
377 * fonts or Courier fonts). Only one
378 * run is allowed and it must be at
379 * the end. This allows a monospaced
380 * font to vary the side bearing
381 * values for each glyph. */
382 /*UnsizedArrayOf<UFWORD>advancesX;*/
383 /* TODO Document. */
384 public:
385 DEFINE_SIZE_ARRAY (0, longMetricZ);
386 };
387
388 struct hmtx : hmtxvmtx<hmtx, hhea, HVAR> {
389 static constexpr hb_tag_t tableTag = HB_OT_TAG_hmtx;
390 static constexpr hb_tag_t variationsTag = HB_OT_TAG_HVAR;
391 static constexpr bool is_horizontal = true;
392 };
393 struct vmtx : hmtxvmtx<vmtx, vhea, VVAR> {
394 static constexpr hb_tag_t tableTag = HB_OT_TAG_vmtx;
395 static constexpr hb_tag_t variationsTag = HB_OT_TAG_VVAR;
396 static constexpr bool is_horizontal = false;
397 };
398
399 struct hmtx_accelerator_t : hmtx::accelerator_t {
400 hmtx_accelerator_t (hb_face_t *face) : hmtx::accelerator_t (face) {}
401 };
402 struct vmtx_accelerator_t : vmtx::accelerator_t {
403 vmtx_accelerator_t (hb_face_t *face) : vmtx::accelerator_t (face) {}
404 };
405
406 } /* namespace OT */
407
408
409 #endif /* HB_OT_HMTX_TABLE_HH */