1/*
2 * Copyright © 2016 Igalia S.L.
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 * Igalia Author(s): Frédéric Wang
25 */
26
27#ifndef HB_OT_MATH_TABLE_HH
28#define HB_OT_MATH_TABLE_HH
29
30#include "hb-open-type.hh"
31#include "hb-ot-layout-common.hh"
32#include "hb-ot-math.h"
33
34namespace OT {
35
36
37struct MathValueRecord
38{
39 hb_position_t get_x_value (hb_font_t *font, const void *base) const
40 { return font->em_scale_x (value) + (base+deviceTable).get_x_delta (font); }
41 hb_position_t get_y_value (hb_font_t *font, const void *base) const
42 { return font->em_scale_y (value) + (base+deviceTable).get_y_delta (font); }
43
44 bool sanitize (hb_sanitize_context_t *c, const void *base) const
45 {
46 TRACE_SANITIZE (this);
47 return_trace (c->check_struct (this) && deviceTable.sanitize (c, base));
48 }
49
50 protected:
51 HBINT16 value; /* The X or Y value in design units */
52 OffsetTo<Device> deviceTable; /* Offset to the device table - from the
53 * beginning of parent table. May be NULL.
54 * Suggested format for device table is 1. */
55
56 public:
57 DEFINE_SIZE_STATIC (4);
58};
59
60struct MathConstants
61{
62 bool sanitize_math_value_records (hb_sanitize_context_t *c) const
63 {
64 TRACE_SANITIZE (this);
65
66 unsigned int count = ARRAY_LENGTH (mathValueRecords);
67 for (unsigned int i = 0; i < count; i++)
68 if (!mathValueRecords[i].sanitize (c, this))
69 return_trace (false);
70
71 return_trace (true);
72 }
73
74 bool sanitize (hb_sanitize_context_t *c) const
75 {
76 TRACE_SANITIZE (this);
77 return_trace (c->check_struct (this) && sanitize_math_value_records (c));
78 }
79
80 hb_position_t get_value (hb_ot_math_constant_t constant,
81 hb_font_t *font) const
82 {
83 switch (constant) {
84
85 case HB_OT_MATH_CONSTANT_SCRIPT_PERCENT_SCALE_DOWN:
86 case HB_OT_MATH_CONSTANT_SCRIPT_SCRIPT_PERCENT_SCALE_DOWN:
87 return percentScaleDown[constant - HB_OT_MATH_CONSTANT_SCRIPT_PERCENT_SCALE_DOWN];
88
89 case HB_OT_MATH_CONSTANT_DELIMITED_SUB_FORMULA_MIN_HEIGHT:
90 case HB_OT_MATH_CONSTANT_DISPLAY_OPERATOR_MIN_HEIGHT:
91 return font->em_scale_y (minHeight[constant - HB_OT_MATH_CONSTANT_DELIMITED_SUB_FORMULA_MIN_HEIGHT]);
92
93 case HB_OT_MATH_CONSTANT_RADICAL_KERN_AFTER_DEGREE:
94 case HB_OT_MATH_CONSTANT_RADICAL_KERN_BEFORE_DEGREE:
95 case HB_OT_MATH_CONSTANT_SKEWED_FRACTION_HORIZONTAL_GAP:
96 case HB_OT_MATH_CONSTANT_SPACE_AFTER_SCRIPT:
97 return mathValueRecords[constant - HB_OT_MATH_CONSTANT_MATH_LEADING].get_x_value (font, this);
98
99 case HB_OT_MATH_CONSTANT_ACCENT_BASE_HEIGHT:
100 case HB_OT_MATH_CONSTANT_AXIS_HEIGHT:
101 case HB_OT_MATH_CONSTANT_FLATTENED_ACCENT_BASE_HEIGHT:
102 case HB_OT_MATH_CONSTANT_FRACTION_DENOMINATOR_DISPLAY_STYLE_SHIFT_DOWN:
103 case HB_OT_MATH_CONSTANT_FRACTION_DENOMINATOR_GAP_MIN:
104 case HB_OT_MATH_CONSTANT_FRACTION_DENOMINATOR_SHIFT_DOWN:
105 case HB_OT_MATH_CONSTANT_FRACTION_DENOM_DISPLAY_STYLE_GAP_MIN:
106 case HB_OT_MATH_CONSTANT_FRACTION_NUMERATOR_DISPLAY_STYLE_SHIFT_UP:
107 case HB_OT_MATH_CONSTANT_FRACTION_NUMERATOR_GAP_MIN:
108 case HB_OT_MATH_CONSTANT_FRACTION_NUMERATOR_SHIFT_UP:
109 case HB_OT_MATH_CONSTANT_FRACTION_NUM_DISPLAY_STYLE_GAP_MIN:
110 case HB_OT_MATH_CONSTANT_FRACTION_RULE_THICKNESS:
111 case HB_OT_MATH_CONSTANT_LOWER_LIMIT_BASELINE_DROP_MIN:
112 case HB_OT_MATH_CONSTANT_LOWER_LIMIT_GAP_MIN:
113 case HB_OT_MATH_CONSTANT_MATH_LEADING:
114 case HB_OT_MATH_CONSTANT_OVERBAR_EXTRA_ASCENDER:
115 case HB_OT_MATH_CONSTANT_OVERBAR_RULE_THICKNESS:
116 case HB_OT_MATH_CONSTANT_OVERBAR_VERTICAL_GAP:
117 case HB_OT_MATH_CONSTANT_RADICAL_DISPLAY_STYLE_VERTICAL_GAP:
118 case HB_OT_MATH_CONSTANT_RADICAL_EXTRA_ASCENDER:
119 case HB_OT_MATH_CONSTANT_RADICAL_RULE_THICKNESS:
120 case HB_OT_MATH_CONSTANT_RADICAL_VERTICAL_GAP:
121 case HB_OT_MATH_CONSTANT_SKEWED_FRACTION_VERTICAL_GAP:
122 case HB_OT_MATH_CONSTANT_STACK_BOTTOM_DISPLAY_STYLE_SHIFT_DOWN:
123 case HB_OT_MATH_CONSTANT_STACK_BOTTOM_SHIFT_DOWN:
124 case HB_OT_MATH_CONSTANT_STACK_DISPLAY_STYLE_GAP_MIN:
125 case HB_OT_MATH_CONSTANT_STACK_GAP_MIN:
126 case HB_OT_MATH_CONSTANT_STACK_TOP_DISPLAY_STYLE_SHIFT_UP:
127 case HB_OT_MATH_CONSTANT_STACK_TOP_SHIFT_UP:
128 case HB_OT_MATH_CONSTANT_STRETCH_STACK_BOTTOM_SHIFT_DOWN:
129 case HB_OT_MATH_CONSTANT_STRETCH_STACK_GAP_ABOVE_MIN:
130 case HB_OT_MATH_CONSTANT_STRETCH_STACK_GAP_BELOW_MIN:
131 case HB_OT_MATH_CONSTANT_STRETCH_STACK_TOP_SHIFT_UP:
132 case HB_OT_MATH_CONSTANT_SUBSCRIPT_BASELINE_DROP_MIN:
133 case HB_OT_MATH_CONSTANT_SUBSCRIPT_SHIFT_DOWN:
134 case HB_OT_MATH_CONSTANT_SUBSCRIPT_TOP_MAX:
135 case HB_OT_MATH_CONSTANT_SUB_SUPERSCRIPT_GAP_MIN:
136 case HB_OT_MATH_CONSTANT_SUPERSCRIPT_BASELINE_DROP_MAX:
137 case HB_OT_MATH_CONSTANT_SUPERSCRIPT_BOTTOM_MAX_WITH_SUBSCRIPT:
138 case HB_OT_MATH_CONSTANT_SUPERSCRIPT_BOTTOM_MIN:
139 case HB_OT_MATH_CONSTANT_SUPERSCRIPT_SHIFT_UP:
140 case HB_OT_MATH_CONSTANT_SUPERSCRIPT_SHIFT_UP_CRAMPED:
141 case HB_OT_MATH_CONSTANT_UNDERBAR_EXTRA_DESCENDER:
142 case HB_OT_MATH_CONSTANT_UNDERBAR_RULE_THICKNESS:
143 case HB_OT_MATH_CONSTANT_UNDERBAR_VERTICAL_GAP:
144 case HB_OT_MATH_CONSTANT_UPPER_LIMIT_BASELINE_RISE_MIN:
145 case HB_OT_MATH_CONSTANT_UPPER_LIMIT_GAP_MIN:
146 return mathValueRecords[constant - HB_OT_MATH_CONSTANT_MATH_LEADING].get_y_value (font, this);
147
148 case HB_OT_MATH_CONSTANT_RADICAL_DEGREE_BOTTOM_RAISE_PERCENT:
149 return radicalDegreeBottomRaisePercent;
150
151 default:
152 return 0;
153 }
154 }
155
156 protected:
157 HBINT16 percentScaleDown[2];
158 HBUINT16 minHeight[2];
159 MathValueRecord mathValueRecords[51];
160 HBINT16 radicalDegreeBottomRaisePercent;
161
162 public:
163 DEFINE_SIZE_STATIC (214);
164};
165
166struct MathItalicsCorrectionInfo
167{
168 bool sanitize (hb_sanitize_context_t *c) const
169 {
170 TRACE_SANITIZE (this);
171 return_trace (c->check_struct (this) &&
172 coverage.sanitize (c, this) &&
173 italicsCorrection.sanitize (c, this));
174 }
175
176 hb_position_t get_value (hb_codepoint_t glyph,
177 hb_font_t *font) const
178 {
179 unsigned int index = (this+coverage).get_coverage (glyph);
180 return italicsCorrection[index].get_x_value (font, this);
181 }
182
183 protected:
184 OffsetTo<Coverage> coverage; /* Offset to Coverage table -
185 * from the beginning of
186 * MathItalicsCorrectionInfo
187 * table. */
188 ArrayOf<MathValueRecord> italicsCorrection; /* Array of MathValueRecords
189 * defining italics correction
190 * values for each
191 * covered glyph. */
192
193 public:
194 DEFINE_SIZE_ARRAY (4, italicsCorrection);
195};
196
197struct MathTopAccentAttachment
198{
199 bool sanitize (hb_sanitize_context_t *c) const
200 {
201 TRACE_SANITIZE (this);
202 return_trace (c->check_struct (this) &&
203 topAccentCoverage.sanitize (c, this) &&
204 topAccentAttachment.sanitize (c, this));
205 }
206
207 hb_position_t get_value (hb_codepoint_t glyph,
208 hb_font_t *font) const
209 {
210 unsigned int index = (this+topAccentCoverage).get_coverage (glyph);
211 if (index == NOT_COVERED)
212 return font->get_glyph_h_advance (glyph) / 2;
213 return topAccentAttachment[index].get_x_value (font, this);
214 }
215
216 protected:
217 OffsetTo<Coverage> topAccentCoverage; /* Offset to Coverage table -
218 * from the beginning of
219 * MathTopAccentAttachment
220 * table. */
221 ArrayOf<MathValueRecord> topAccentAttachment; /* Array of MathValueRecords
222 * defining top accent
223 * attachment points for each
224 * covered glyph. */
225
226 public:
227 DEFINE_SIZE_ARRAY (2 + 2, topAccentAttachment);
228};
229
230struct MathKern
231{
232 bool sanitize_math_value_records (hb_sanitize_context_t *c) const
233 {
234 TRACE_SANITIZE (this);
235 unsigned int count = 2 * heightCount + 1;
236 for (unsigned int i = 0; i < count; i++)
237 if (!mathValueRecordsZ.arrayZ[i].sanitize (c, this)) return_trace (false);
238 return_trace (true);
239 }
240
241 bool sanitize (hb_sanitize_context_t *c) const
242 {
243 TRACE_SANITIZE (this);
244 return_trace (c->check_struct (this) &&
245 c->check_array (mathValueRecordsZ.arrayZ, 2 * heightCount + 1) &&
246 sanitize_math_value_records (c));
247 }
248
249 hb_position_t get_value (hb_position_t correction_height, hb_font_t *font) const
250 {
251 const MathValueRecord* correctionHeight = mathValueRecordsZ.arrayZ;
252 const MathValueRecord* kernValue = mathValueRecordsZ.arrayZ + heightCount;
253 int sign = font->y_scale < 0 ? -1 : +1;
254
255 /* The description of the MathKern table is a ambiguous, but interpreting
256 * "between the two heights found at those indexes" for 0 < i < len as
257 *
258 * correctionHeight[i-1] < correction_height <= correctionHeight[i]
259 *
260 * makes the result consistent with the limit cases and we can just use the
261 * binary search algorithm of std::upper_bound:
262 */
263 unsigned int i = 0;
264 unsigned int count = heightCount;
265 while (count > 0)
266 {
267 unsigned int half = count / 2;
268 hb_position_t height = correctionHeight[i + half].get_y_value (font, this);
269 if (sign * height < sign * correction_height)
270 {
271 i += half + 1;
272 count -= half + 1;
273 } else
274 count = half;
275 }
276 return kernValue[i].get_x_value (font, this);
277 }
278
279 protected:
280 HBUINT16 heightCount;
281 UnsizedArrayOf<MathValueRecord>
282 mathValueRecordsZ;
283 /* Array of correction heights at
284 * which the kern value changes.
285 * Sorted by the height value in
286 * design units (heightCount entries),
287 * Followed by:
288 * Array of kern values corresponding
289 * to heights. (heightCount+1 entries).
290 */
291
292 public:
293 DEFINE_SIZE_ARRAY (2, mathValueRecordsZ);
294};
295
296struct MathKernInfoRecord
297{
298 bool sanitize (hb_sanitize_context_t *c, const void *base) const
299 {
300 TRACE_SANITIZE (this);
301
302 unsigned int count = ARRAY_LENGTH (mathKern);
303 for (unsigned int i = 0; i < count; i++)
304 if (unlikely (!mathKern[i].sanitize (c, base)))
305 return_trace (false);
306
307 return_trace (true);
308 }
309
310 hb_position_t get_kerning (hb_ot_math_kern_t kern,
311 hb_position_t correction_height,
312 hb_font_t *font,
313 const void *base) const
314 {
315 unsigned int idx = kern;
316 if (unlikely (idx >= ARRAY_LENGTH (mathKern))) return 0;
317 return (base+mathKern[idx]).get_value (correction_height, font);
318 }
319
320 protected:
321 /* Offset to MathKern table for each corner -
322 * from the beginning of MathKernInfo table. May be NULL. */
323 OffsetTo<MathKern> mathKern[4];
324
325 public:
326 DEFINE_SIZE_STATIC (8);
327};
328
329struct MathKernInfo
330{
331 bool sanitize (hb_sanitize_context_t *c) const
332 {
333 TRACE_SANITIZE (this);
334 return_trace (c->check_struct (this) &&
335 mathKernCoverage.sanitize (c, this) &&
336 mathKernInfoRecords.sanitize (c, this));
337 }
338
339 hb_position_t get_kerning (hb_codepoint_t glyph,
340 hb_ot_math_kern_t kern,
341 hb_position_t correction_height,
342 hb_font_t *font) const
343 {
344 unsigned int index = (this+mathKernCoverage).get_coverage (glyph);
345 return mathKernInfoRecords[index].get_kerning (kern, correction_height, font, this);
346 }
347
348 protected:
349 OffsetTo<Coverage>
350 mathKernCoverage;
351 /* Offset to Coverage table -
352 * from the beginning of the
353 * MathKernInfo table. */
354 ArrayOf<MathKernInfoRecord>
355 mathKernInfoRecords;
356 /* Array of MathKernInfoRecords,
357 * per-glyph information for
358 * mathematical positioning
359 * of subscripts and
360 * superscripts. */
361
362 public:
363 DEFINE_SIZE_ARRAY (4, mathKernInfoRecords);
364};
365
366struct MathGlyphInfo
367{
368 bool sanitize (hb_sanitize_context_t *c) const
369 {
370 TRACE_SANITIZE (this);
371 return_trace (c->check_struct (this) &&
372 mathItalicsCorrectionInfo.sanitize (c, this) &&
373 mathTopAccentAttachment.sanitize (c, this) &&
374 extendedShapeCoverage.sanitize (c, this) &&
375 mathKernInfo.sanitize (c, this));
376 }
377
378 hb_position_t
379 get_italics_correction (hb_codepoint_t glyph, hb_font_t *font) const
380 { return (this+mathItalicsCorrectionInfo).get_value (glyph, font); }
381
382 hb_position_t
383 get_top_accent_attachment (hb_codepoint_t glyph, hb_font_t *font) const
384 { return (this+mathTopAccentAttachment).get_value (glyph, font); }
385
386 bool is_extended_shape (hb_codepoint_t glyph) const
387 { return (this+extendedShapeCoverage).get_coverage (glyph) != NOT_COVERED; }
388
389 hb_position_t get_kerning (hb_codepoint_t glyph,
390 hb_ot_math_kern_t kern,
391 hb_position_t correction_height,
392 hb_font_t *font) const
393 { return (this+mathKernInfo).get_kerning (glyph, kern, correction_height, font); }
394
395 protected:
396 /* Offset to MathItalicsCorrectionInfo table -
397 * from the beginning of MathGlyphInfo table. */
398 OffsetTo<MathItalicsCorrectionInfo> mathItalicsCorrectionInfo;
399
400 /* Offset to MathTopAccentAttachment table -
401 * from the beginning of MathGlyphInfo table. */
402 OffsetTo<MathTopAccentAttachment> mathTopAccentAttachment;
403
404 /* Offset to coverage table for Extended Shape glyphs -
405 * from the beginning of MathGlyphInfo table. When the left or right glyph of
406 * a box is an extended shape variant, the (ink) box (and not the default
407 * position defined by values in MathConstants table) should be used for
408 * vertical positioning purposes. May be NULL.. */
409 OffsetTo<Coverage> extendedShapeCoverage;
410
411 /* Offset to MathKernInfo table -
412 * from the beginning of MathGlyphInfo table. */
413 OffsetTo<MathKernInfo> mathKernInfo;
414
415 public:
416 DEFINE_SIZE_STATIC (8);
417};
418
419struct MathGlyphVariantRecord
420{
421 friend struct MathGlyphConstruction;
422
423 bool sanitize (hb_sanitize_context_t *c) const
424 {
425 TRACE_SANITIZE (this);
426 return_trace (c->check_struct (this));
427 }
428
429 protected:
430 HBGlyphID variantGlyph; /* Glyph ID for the variant. */
431 HBUINT16 advanceMeasurement; /* Advance width/height, in design units, of the
432 * variant, in the direction of requested
433 * glyph extension. */
434
435 public:
436 DEFINE_SIZE_STATIC (4);
437};
438
439struct PartFlags : HBUINT16
440{
441 enum Flags {
442 Extender = 0x0001u, /* If set, the part can be skipped or repeated. */
443
444 Defined = 0x0001u, /* All defined flags. */
445 };
446
447 public:
448 DEFINE_SIZE_STATIC (2);
449};
450
451struct MathGlyphPartRecord
452{
453 bool sanitize (hb_sanitize_context_t *c) const
454 {
455 TRACE_SANITIZE (this);
456 return_trace (c->check_struct (this));
457 }
458
459 void extract (hb_ot_math_glyph_part_t &out,
460 int64_t mult,
461 hb_font_t *font) const
462 {
463 out.glyph = glyph;
464
465 out.start_connector_length = font->em_mult (startConnectorLength, mult);
466 out.end_connector_length = font->em_mult (endConnectorLength, mult);
467 out.full_advance = font->em_mult (fullAdvance, mult);
468
469 static_assert ((unsigned int) HB_OT_MATH_GLYPH_PART_FLAG_EXTENDER ==
470 (unsigned int) PartFlags::Extender, "");
471
472 out.flags = (hb_ot_math_glyph_part_flags_t)
473 (unsigned int)
474 (partFlags & PartFlags::Defined);
475 }
476
477 protected:
478 HBGlyphID glyph; /* Glyph ID for the part. */
479 HBUINT16 startConnectorLength;
480 /* Advance width/ height of the straight bar
481 * connector material, in design units, is at
482 * the beginning of the glyph, in the
483 * direction of the extension. */
484 HBUINT16 endConnectorLength;
485 /* Advance width/ height of the straight bar
486 * connector material, in design units, is at
487 * the end of the glyph, in the direction of
488 * the extension. */
489 HBUINT16 fullAdvance; /* Full advance width/height for this part,
490 * in the direction of the extension.
491 * In design units. */
492 PartFlags partFlags; /* Part qualifiers. */
493
494 public:
495 DEFINE_SIZE_STATIC (10);
496};
497
498struct MathGlyphAssembly
499{
500 bool sanitize (hb_sanitize_context_t *c) const
501 {
502 TRACE_SANITIZE (this);
503 return_trace (c->check_struct (this) &&
504 italicsCorrection.sanitize (c, this) &&
505 partRecords.sanitize (c));
506 }
507
508 unsigned int get_parts (hb_direction_t direction,
509 hb_font_t *font,
510 unsigned int start_offset,
511 unsigned int *parts_count, /* IN/OUT */
512 hb_ot_math_glyph_part_t *parts /* OUT */,
513 hb_position_t *italics_correction /* OUT */) const
514 {
515 if (parts_count)
516 {
517 int64_t mult = font->dir_mult (direction);
518 for (auto _ : hb_zip (partRecords.sub_array (start_offset, parts_count),
519 hb_array (parts, *parts_count)))
520 _.first.extract (_.second, mult, font);
521 }
522
523 if (italics_correction)
524 *italics_correction = italicsCorrection.get_x_value (font, this);
525
526 return partRecords.len;
527 }
528
529 protected:
530 MathValueRecord
531 italicsCorrection;
532 /* Italics correction of this
533 * MathGlyphAssembly. Should not
534 * depend on the assembly size. */
535 ArrayOf<MathGlyphPartRecord>
536 partRecords; /* Array of part records, from
537 * left to right and bottom to
538 * top. */
539
540 public:
541 DEFINE_SIZE_ARRAY (6, partRecords);
542};
543
544struct MathGlyphConstruction
545{
546 bool sanitize (hb_sanitize_context_t *c) const
547 {
548 TRACE_SANITIZE (this);
549 return_trace (c->check_struct (this) &&
550 glyphAssembly.sanitize (c, this) &&
551 mathGlyphVariantRecord.sanitize (c));
552 }
553
554 const MathGlyphAssembly &get_assembly () const { return this+glyphAssembly; }
555
556 unsigned int get_variants (hb_direction_t direction,
557 hb_font_t *font,
558 unsigned int start_offset,
559 unsigned int *variants_count, /* IN/OUT */
560 hb_ot_math_glyph_variant_t *variants /* OUT */) const
561 {
562 if (variants_count)
563 {
564 int64_t mult = font->dir_mult (direction);
565 for (auto _ : hb_zip (mathGlyphVariantRecord.sub_array (start_offset, variants_count),
566 hb_array (variants, *variants_count)))
567 _.second = {_.first.variantGlyph, font->em_mult (_.first.advanceMeasurement, mult)};
568 }
569 return mathGlyphVariantRecord.len;
570 }
571
572 protected:
573 /* Offset to MathGlyphAssembly table for this shape - from the beginning of
574 MathGlyphConstruction table. May be NULL. */
575 OffsetTo<MathGlyphAssembly> glyphAssembly;
576
577 /* MathGlyphVariantRecords for alternative variants of the glyphs. */
578 ArrayOf<MathGlyphVariantRecord> mathGlyphVariantRecord;
579
580 public:
581 DEFINE_SIZE_ARRAY (4, mathGlyphVariantRecord);
582};
583
584struct MathVariants
585{
586 bool sanitize_offsets (hb_sanitize_context_t *c) const
587 {
588 TRACE_SANITIZE (this);
589 unsigned int count = vertGlyphCount + horizGlyphCount;
590 for (unsigned int i = 0; i < count; i++)
591 if (!glyphConstruction.arrayZ[i].sanitize (c, this)) return_trace (false);
592 return_trace (true);
593 }
594
595 bool sanitize (hb_sanitize_context_t *c) const
596 {
597 TRACE_SANITIZE (this);
598 return_trace (c->check_struct (this) &&
599 vertGlyphCoverage.sanitize (c, this) &&
600 horizGlyphCoverage.sanitize (c, this) &&
601 c->check_array (glyphConstruction.arrayZ, vertGlyphCount + horizGlyphCount) &&
602 sanitize_offsets (c));
603 }
604
605 hb_position_t get_min_connector_overlap (hb_direction_t direction,
606 hb_font_t *font) const
607 { return font->em_scale_dir (minConnectorOverlap, direction); }
608
609 unsigned int get_glyph_variants (hb_codepoint_t glyph,
610 hb_direction_t direction,
611 hb_font_t *font,
612 unsigned int start_offset,
613 unsigned int *variants_count, /* IN/OUT */
614 hb_ot_math_glyph_variant_t *variants /* OUT */) const
615 { return get_glyph_construction (glyph, direction, font)
616 .get_variants (direction, font, start_offset, variants_count, variants); }
617
618 unsigned int get_glyph_parts (hb_codepoint_t glyph,
619 hb_direction_t direction,
620 hb_font_t *font,
621 unsigned int start_offset,
622 unsigned int *parts_count, /* IN/OUT */
623 hb_ot_math_glyph_part_t *parts /* OUT */,
624 hb_position_t *italics_correction /* OUT */) const
625 { return get_glyph_construction (glyph, direction, font)
626 .get_assembly ()
627 .get_parts (direction, font,
628 start_offset, parts_count, parts,
629 italics_correction); }
630
631 private:
632 const MathGlyphConstruction &
633 get_glyph_construction (hb_codepoint_t glyph,
634 hb_direction_t direction,
635 hb_font_t *font HB_UNUSED) const
636 {
637 bool vertical = HB_DIRECTION_IS_VERTICAL (direction);
638 unsigned int count = vertical ? vertGlyphCount : horizGlyphCount;
639 const OffsetTo<Coverage> &coverage = vertical ? vertGlyphCoverage
640 : horizGlyphCoverage;
641
642 unsigned int index = (this+coverage).get_coverage (glyph);
643 if (unlikely (index >= count)) return Null (MathGlyphConstruction);
644
645 if (!vertical)
646 index += vertGlyphCount;
647
648 return this+glyphConstruction[index];
649 }
650
651 protected:
652 HBUINT16 minConnectorOverlap;
653 /* Minimum overlap of connecting
654 * glyphs during glyph construction,
655 * in design units. */
656 OffsetTo<Coverage> vertGlyphCoverage;
657 /* Offset to Coverage table -
658 * from the beginning of MathVariants
659 * table. */
660 OffsetTo<Coverage> horizGlyphCoverage;
661 /* Offset to Coverage table -
662 * from the beginning of MathVariants
663 * table. */
664 HBUINT16 vertGlyphCount; /* Number of glyphs for which
665 * information is provided for
666 * vertically growing variants. */
667 HBUINT16 horizGlyphCount;/* Number of glyphs for which
668 * information is provided for
669 * horizontally growing variants. */
670
671 /* Array of offsets to MathGlyphConstruction tables - from the beginning of
672 the MathVariants table, for shapes growing in vertical/horizontal
673 direction. */
674 UnsizedArrayOf<OffsetTo<MathGlyphConstruction>>
675 glyphConstruction;
676
677 public:
678 DEFINE_SIZE_ARRAY (10, glyphConstruction);
679};
680
681
682/*
683 * MATH -- Mathematical typesetting
684 * https://docs.microsoft.com/en-us/typography/opentype/spec/math
685 */
686
687struct MATH
688{
689 static constexpr hb_tag_t tableTag = HB_OT_TAG_MATH;
690
691 bool has_data () const { return version.to_int (); }
692
693 bool sanitize (hb_sanitize_context_t *c) const
694 {
695 TRACE_SANITIZE (this);
696 return_trace (version.sanitize (c) &&
697 likely (version.major == 1) &&
698 mathConstants.sanitize (c, this) &&
699 mathGlyphInfo.sanitize (c, this) &&
700 mathVariants.sanitize (c, this));
701 }
702
703 hb_position_t get_constant (hb_ot_math_constant_t constant,
704 hb_font_t *font) const
705 { return (this+mathConstants).get_value (constant, font); }
706
707 const MathGlyphInfo &get_glyph_info () const { return this+mathGlyphInfo; }
708
709 const MathVariants &get_variants () const { return this+mathVariants; }
710
711 protected:
712 FixedVersion<>version; /* Version of the MATH table
713 * initially set to 0x00010000u */
714 OffsetTo<MathConstants>
715 mathConstants; /* MathConstants table */
716 OffsetTo<MathGlyphInfo>
717 mathGlyphInfo; /* MathGlyphInfo table */
718 OffsetTo<MathVariants>
719 mathVariants; /* MathVariants table */
720
721 public:
722 DEFINE_SIZE_STATIC (10);
723};
724
725} /* namespace OT */
726
727
728#endif /* HB_OT_MATH_TABLE_HH */
729