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 inline 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 inline 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 inline 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 nullptr.
54 * Suggested format for device table is 1. */
55
56 public:
57 DEFINE_SIZE_STATIC (4);
58};
59
60struct MathConstants
61{
62 inline 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 inline 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 inline 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 inline 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 inline 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 inline 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 inline 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 inline 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 (!mathValueRecords[i].sanitize (c, this)) return_trace (false);
238 return_trace (true);
239 }
240
241 inline bool sanitize (hb_sanitize_context_t *c) const
242 {
243 TRACE_SANITIZE (this);
244 return_trace (c->check_struct (this) &&
245 c->check_array (mathValueRecords,
246 mathValueRecords[0].static_size,
247 2 * heightCount + 1) &&
248 sanitize_math_value_records (c));
249 }
250
251 inline hb_position_t get_value (hb_position_t correction_height, hb_font_t *font) const
252 {
253 const MathValueRecord* correctionHeight = mathValueRecords;
254 const MathValueRecord* kernValue = mathValueRecords + heightCount;
255 int sign = font->y_scale < 0 ? -1 : +1;
256
257 /* The description of the MathKern table is a ambiguous, but interpreting
258 * "between the two heights found at those indexes" for 0 < i < len as
259 *
260 * correctionHeight[i-1] < correction_height <= correctionHeight[i]
261 *
262 * makes the result consistent with the limit cases and we can just use the
263 * binary search algorithm of std::upper_bound:
264 */
265 unsigned int i = 0;
266 unsigned int count = heightCount;
267 while (count > 0)
268 {
269 unsigned int half = count / 2;
270 hb_position_t height = correctionHeight[i + half].get_y_value(font, this);
271 if (sign * height < sign * correction_height)
272 {
273 i += half + 1;
274 count -= half + 1;
275 } else
276 count = half;
277 }
278 return kernValue[i].get_x_value(font, this);
279 }
280
281 protected:
282 HBUINT16 heightCount;
283 MathValueRecord mathValueRecords[VAR]; /* 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, mathValueRecords);
294};
295
296struct MathKernInfoRecord
297{
298 inline 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 inline 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 nullptr. */
323 OffsetTo<MathKern> mathKern[4];
324
325 public:
326 DEFINE_SIZE_STATIC (8);
327};
328
329struct MathKernInfo
330{
331 inline 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 inline 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> mathKernCoverage; /* Offset to Coverage table -
350 * from the beginning of the
351 * MathKernInfo table. */
352 ArrayOf<MathKernInfoRecord> mathKernInfoRecords; /* Array of
353 * MathKernInfoRecords,
354 * per-glyph information for
355 * mathematical positioning
356 * of subscripts and
357 * superscripts. */
358
359 public:
360 DEFINE_SIZE_ARRAY (4, mathKernInfoRecords);
361};
362
363struct MathGlyphInfo
364{
365 inline bool sanitize (hb_sanitize_context_t *c) const
366 {
367 TRACE_SANITIZE (this);
368 return_trace (c->check_struct (this) &&
369 mathItalicsCorrectionInfo.sanitize (c, this) &&
370 mathTopAccentAttachment.sanitize (c, this) &&
371 extendedShapeCoverage.sanitize (c, this) &&
372 mathKernInfo.sanitize(c, this));
373 }
374
375 inline hb_position_t
376 get_italics_correction (hb_codepoint_t glyph, hb_font_t *font) const
377 { return (this+mathItalicsCorrectionInfo).get_value (glyph, font); }
378
379 inline hb_position_t
380 get_top_accent_attachment (hb_codepoint_t glyph, hb_font_t *font) const
381 { return (this+mathTopAccentAttachment).get_value (glyph, font); }
382
383 inline bool is_extended_shape (hb_codepoint_t glyph) const
384 { return (this+extendedShapeCoverage).get_coverage (glyph) != NOT_COVERED; }
385
386 inline hb_position_t get_kerning (hb_codepoint_t glyph,
387 hb_ot_math_kern_t kern,
388 hb_position_t correction_height,
389 hb_font_t *font) const
390 { return (this+mathKernInfo).get_kerning (glyph, kern, correction_height, font); }
391
392 protected:
393 /* Offset to MathItalicsCorrectionInfo table -
394 * from the beginning of MathGlyphInfo table. */
395 OffsetTo<MathItalicsCorrectionInfo> mathItalicsCorrectionInfo;
396
397 /* Offset to MathTopAccentAttachment table -
398 * from the beginning of MathGlyphInfo table. */
399 OffsetTo<MathTopAccentAttachment> mathTopAccentAttachment;
400
401 /* Offset to coverage table for Extended Shape glyphs -
402 * from the beginning of MathGlyphInfo table. When the left or right glyph of
403 * a box is an extended shape variant, the (ink) box (and not the default
404 * position defined by values in MathConstants table) should be used for
405 * vertical positioning purposes. May be nullptr.. */
406 OffsetTo<Coverage> extendedShapeCoverage;
407
408 /* Offset to MathKernInfo table -
409 * from the beginning of MathGlyphInfo table. */
410 OffsetTo<MathKernInfo> mathKernInfo;
411
412 public:
413 DEFINE_SIZE_STATIC (8);
414};
415
416struct MathGlyphVariantRecord
417{
418 friend struct MathGlyphConstruction;
419
420 inline bool sanitize (hb_sanitize_context_t *c) const
421 {
422 TRACE_SANITIZE (this);
423 return_trace (c->check_struct (this));
424 }
425
426 protected:
427 GlyphID variantGlyph; /* Glyph ID for the variant. */
428 HBUINT16 advanceMeasurement; /* Advance width/height, in design units, of the
429 * variant, in the direction of requested
430 * glyph extension. */
431
432 public:
433 DEFINE_SIZE_STATIC (4);
434};
435
436struct PartFlags : HBUINT16
437{
438 enum Flags {
439 Extender = 0x0001u, /* If set, the part can be skipped or repeated. */
440
441 Defined = 0x0001u, /* All defined flags. */
442 };
443
444 public:
445 DEFINE_SIZE_STATIC (2);
446};
447
448struct MathGlyphPartRecord
449{
450 inline bool sanitize (hb_sanitize_context_t *c) const
451 {
452 TRACE_SANITIZE (this);
453 return_trace (c->check_struct (this));
454 }
455
456 inline void extract (hb_ot_math_glyph_part_t &out,
457 int scale,
458 hb_font_t *font) const
459 {
460 out.glyph = glyph;
461
462 out.start_connector_length = font->em_scale (startConnectorLength, scale);
463 out.end_connector_length = font->em_scale (endConnectorLength, scale);
464 out.full_advance = font->em_scale (fullAdvance, scale);
465
466 static_assert ((unsigned int) HB_MATH_GLYPH_PART_FLAG_EXTENDER ==
467 (unsigned int) PartFlags::Extender, "");
468
469 out.flags = (hb_ot_math_glyph_part_flags_t)
470 (unsigned int)
471 (partFlags & PartFlags::Defined);
472 }
473
474 protected:
475 GlyphID glyph; /* Glyph ID for the part. */
476 HBUINT16 startConnectorLength; /* Advance width/ height of the straight bar
477 * connector material, in design units, is at
478 * the beginning of the glyph, in the
479 * direction of the extension. */
480 HBUINT16 endConnectorLength; /* Advance width/ height of the straight bar
481 * connector material, in design units, is at
482 * the end of the glyph, in the direction of
483 * the extension. */
484 HBUINT16 fullAdvance; /* Full advance width/height for this part,
485 * in the direction of the extension.
486 * In design units. */
487 PartFlags partFlags; /* Part qualifiers. */
488
489 public:
490 DEFINE_SIZE_STATIC (10);
491};
492
493struct MathGlyphAssembly
494{
495 inline bool sanitize (hb_sanitize_context_t *c) const
496 {
497 TRACE_SANITIZE (this);
498 return_trace (c->check_struct (this) &&
499 italicsCorrection.sanitize(c, this) &&
500 partRecords.sanitize(c));
501 }
502
503 inline unsigned int get_parts (hb_direction_t direction,
504 hb_font_t *font,
505 unsigned int start_offset,
506 unsigned int *parts_count, /* IN/OUT */
507 hb_ot_math_glyph_part_t *parts /* OUT */,
508 hb_position_t *italics_correction /* OUT */) const
509 {
510 if (parts_count)
511 {
512 int scale = font->dir_scale (direction);
513 const MathGlyphPartRecord *arr =
514 partRecords.sub_array (start_offset, parts_count);
515 unsigned int count = *parts_count;
516 for (unsigned int i = 0; i < count; i++)
517 arr[i].extract (parts[i], scale, font);
518 }
519
520 if (italics_correction)
521 *italics_correction = italicsCorrection.get_x_value (font, this);
522
523 return partRecords.len;
524 }
525
526 protected:
527 MathValueRecord italicsCorrection; /* Italics correction of this
528 * MathGlyphAssembly. Should not
529 * depend on the assembly size. */
530 ArrayOf<MathGlyphPartRecord> partRecords; /* Array of part records, from
531 * left to right and bottom to
532 * top. */
533
534 public:
535 DEFINE_SIZE_ARRAY (6, partRecords);
536};
537
538struct MathGlyphConstruction
539{
540 inline bool sanitize (hb_sanitize_context_t *c) const
541 {
542 TRACE_SANITIZE (this);
543 return_trace (c->check_struct (this) &&
544 glyphAssembly.sanitize(c, this) &&
545 mathGlyphVariantRecord.sanitize(c));
546 }
547
548 inline const MathGlyphAssembly &get_assembly (void) const
549 { return this+glyphAssembly; }
550
551 inline unsigned int get_variants (hb_direction_t direction,
552 hb_font_t *font,
553 unsigned int start_offset,
554 unsigned int *variants_count, /* IN/OUT */
555 hb_ot_math_glyph_variant_t *variants /* OUT */) const
556 {
557 if (variants_count)
558 {
559 int scale = font->dir_scale (direction);
560 const MathGlyphVariantRecord *arr =
561 mathGlyphVariantRecord.sub_array (start_offset, variants_count);
562 unsigned int count = *variants_count;
563 for (unsigned int i = 0; i < count; i++)
564 {
565 variants[i].glyph = arr[i].variantGlyph;
566 variants[i].advance = font->em_scale (arr[i].advanceMeasurement, scale);
567 }
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 nullptr. */
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 inline 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[i].sanitize (c, this)) return_trace (false);
592 return_trace (true);
593 }
594
595 inline 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,
602 glyphConstruction[0].static_size,
603 vertGlyphCount + horizGlyphCount) &&
604 sanitize_offsets (c));
605 }
606
607 inline hb_position_t get_min_connector_overlap (hb_direction_t direction,
608 hb_font_t *font) const
609 { return font->em_scale_dir (minConnectorOverlap, direction); }
610
611 inline unsigned int get_glyph_variants (hb_codepoint_t glyph,
612 hb_direction_t direction,
613 hb_font_t *font,
614 unsigned int start_offset,
615 unsigned int *variants_count, /* IN/OUT */
616 hb_ot_math_glyph_variant_t *variants /* OUT */) const
617 { return get_glyph_construction (glyph, direction, font)
618 .get_variants (direction, font, start_offset, variants_count, variants); }
619
620 inline unsigned int get_glyph_parts (hb_codepoint_t glyph,
621 hb_direction_t direction,
622 hb_font_t *font,
623 unsigned int start_offset,
624 unsigned int *parts_count, /* IN/OUT */
625 hb_ot_math_glyph_part_t *parts /* OUT */,
626 hb_position_t *italics_correction /* OUT */) const
627 { return get_glyph_construction (glyph, direction, font)
628 .get_assembly ()
629 .get_parts (direction, font,
630 start_offset, parts_count, parts,
631 italics_correction); }
632
633 private:
634 inline const MathGlyphConstruction &
635 get_glyph_construction (hb_codepoint_t glyph,
636 hb_direction_t direction,
637 hb_font_t *font) const
638 {
639 bool vertical = HB_DIRECTION_IS_VERTICAL (direction);
640 unsigned int count = vertical ? vertGlyphCount : horizGlyphCount;
641 const OffsetTo<Coverage> &coverage = vertical ? vertGlyphCoverage
642 : horizGlyphCoverage;
643
644 unsigned int index = (this+coverage).get_coverage (glyph);
645 if (unlikely (index >= count)) return Null(MathGlyphConstruction);
646
647 if (!vertical)
648 index += vertGlyphCount;
649
650 return this+glyphConstruction[index];
651 }
652
653 protected:
654 HBUINT16 minConnectorOverlap; /* Minimum overlap of connecting
655 * glyphs during glyph construction,
656 * in design units. */
657 OffsetTo<Coverage> vertGlyphCoverage; /* Offset to Coverage table -
658 * from the beginning of MathVariants
659 * table. */
660 OffsetTo<Coverage> horizGlyphCoverage; /* Offset to Coverage table -
661 * from the beginning of MathVariants
662 * table. */
663 HBUINT16 vertGlyphCount; /* Number of glyphs for which
664 * information is provided for
665 * vertically growing variants. */
666 HBUINT16 horizGlyphCount; /* Number of glyphs for which
667 * information is provided for
668 * horizontally growing variants. */
669
670 /* Array of offsets to MathGlyphConstruction tables - from the beginning of
671 the MathVariants table, for shapes growing in vertical/horizontal
672 direction. */
673 OffsetTo<MathGlyphConstruction> glyphConstruction[VAR];
674
675 public:
676 DEFINE_SIZE_ARRAY (10, glyphConstruction);
677};
678
679
680/*
681 * MATH -- Mathematical typesetting
682 * https://docs.microsoft.com/en-us/typography/opentype/spec/math
683 */
684
685struct MATH
686{
687 static const hb_tag_t tableTag = HB_OT_TAG_MATH;
688
689 inline bool has_data (void) const { return version.to_int () != 0; }
690
691 inline bool sanitize (hb_sanitize_context_t *c) const
692 {
693 TRACE_SANITIZE (this);
694 return_trace (version.sanitize (c) &&
695 likely (version.major == 1) &&
696 mathConstants.sanitize (c, this) &&
697 mathGlyphInfo.sanitize (c, this) &&
698 mathVariants.sanitize (c, this));
699 }
700
701 inline hb_position_t get_constant (hb_ot_math_constant_t constant,
702 hb_font_t *font) const
703 { return (this+mathConstants).get_value (constant, font); }
704
705 inline const MathGlyphInfo &get_math_glyph_info (void) const
706 { return this+mathGlyphInfo; }
707
708 inline const MathVariants &get_math_variants (void) const
709 { return this+mathVariants; }
710
711 protected:
712 FixedVersion<>version; /* Version of the MATH table
713 * initially set to 0x00010000u */
714 OffsetTo<MathConstants> mathConstants;/* MathConstants table */
715 OffsetTo<MathGlyphInfo> mathGlyphInfo;/* MathGlyphInfo table */
716 OffsetTo<MathVariants> mathVariants; /* MathVariants table */
717
718 public:
719 DEFINE_SIZE_STATIC (10);
720};
721
722} /* namespace OT */
723
724
725#endif /* HB_OT_MATH_TABLE_HH */
726