summaryrefslogtreecommitdiff
path: root/Build/source/libs/harfbuzz/harfbuzz-src/src/hb-ot-var-gvar-table.hh
blob: bf1039d1d6d484fd6016c370709ee1cbf9d5fabf (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
/*
 * Copyright © 2019  Adobe Inc.
 * Copyright © 2019  Ebrahim Byagowi
 *
 *  This is part of HarfBuzz, a text shaping library.
 *
 * Permission is hereby granted, without written agreement and without
 * license or royalty fees, to use, copy, modify, and distribute this
 * software and its documentation for any purpose, provided that the
 * above copyright notice and the following two paragraphs appear in
 * all copies of this software.
 *
 * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
 * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
 * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
 * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
 * DAMAGE.
 *
 * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
 * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
 * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
 * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
 * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
 *
 * Adobe Author(s): Michiharu Ariza
 */

#ifndef HB_OT_VAR_GVAR_TABLE_HH
#define HB_OT_VAR_GVAR_TABLE_HH

#include "hb-open-type.hh"

/*
 * gvar -- Glyph Variation Table
 * https://docs.microsoft.com/en-us/typography/opentype/spec/gvar
 */
#define HB_OT_TAG_gvar HB_TAG('g','v','a','r')

namespace OT {

struct contour_point_t
{
  void init (float x_ = 0.f, float y_ = 0.f, bool is_end_point_ = false)
  { flag = 0; x = x_; y = y_; is_end_point = is_end_point_; }

  void translate (const contour_point_t &p) { x += p.x; y += p.y; }

  float x = 0.f;
  float y = 0.f;
  uint8_t flag = 0;
  bool is_end_point = false;
};

struct contour_point_vector_t : hb_vector_t<contour_point_t>
{
  void extend (const hb_array_t<contour_point_t> &a)
  {
    unsigned int old_len = length;
    if (unlikely (!resize (old_len + a.length)))
      return;
    auto arrayZ = this->arrayZ + old_len;
    unsigned count = a.length;
    for (unsigned int i = 0; i < count; i++)
      arrayZ[i] = a.arrayZ[i];
  }

  void transform (const float (&matrix)[4])
  {
    if (matrix[0] == 1.f && matrix[1] == 0.f &&
	matrix[2] == 0.f && matrix[3] == 1.f)
      return;
    auto arrayZ = this->arrayZ;
    unsigned count = length;
    for (unsigned i = 0; i < count; i++)
    {
      contour_point_t &p = arrayZ[i];
      float x_ = p.x * matrix[0] + p.y * matrix[2];
	   p.y = p.x * matrix[1] + p.y * matrix[3];
      p.x = x_;
    }
  }

  void translate (const contour_point_t& delta)
  {
    if (delta.x == 0.f && delta.y == 0.f)
      return;
    auto arrayZ = this->arrayZ;
    unsigned count = length;
    for (unsigned i = 0; i < count; i++)
      arrayZ[i].translate (delta);
  }
};

/* https://docs.microsoft.com/en-us/typography/opentype/spec/otvarcommonformats#tuplevariationheader */
struct TupleVariationHeader
{
  unsigned get_size (unsigned axis_count) const
  { return min_size + get_all_tuples (axis_count).get_size (); }

  unsigned get_data_size () const { return varDataSize; }

  const TupleVariationHeader &get_next (unsigned axis_count) const
  { return StructAtOffset<TupleVariationHeader> (this, get_size (axis_count)); }

  float calculate_scalar (hb_array_t<int> coords, unsigned int coord_count,
			  const hb_array_t<const F2DOT14> shared_tuples) const
  {
    hb_array_t<const F2DOT14> peak_tuple;

    if (has_peak ())
      peak_tuple = get_peak_tuple (coord_count);
    else
    {
      unsigned int index = get_index ();
      if (unlikely (index * coord_count >= shared_tuples.length))
	return 0.f;
      peak_tuple = shared_tuples.sub_array (coord_count * index, coord_count);
    }

    hb_array_t<const F2DOT14> start_tuple;
    hb_array_t<const F2DOT14> end_tuple;
    if (has_intermediate ())
    {
      start_tuple = get_start_tuple (coord_count);
      end_tuple = get_end_tuple (coord_count);
    }

    float scalar = 1.f;
    for (unsigned int i = 0; i < coord_count; i++)
    {
      int v = coords[i];
      int peak = peak_tuple[i];
      if (!peak || v == peak) continue;

      if (has_intermediate ())
      {
	int start = start_tuple[i];
	int end = end_tuple[i];
	if (unlikely (start > peak || peak > end ||
		      (start < 0 && end > 0 && peak))) continue;
	if (v < start || v > end) return 0.f;
	if (v < peak)
	{ if (peak != start) scalar *= (float) (v - start) / (peak - start); }
	else
	{ if (peak != end) scalar *= (float) (end - v) / (end - peak); }
      }
      else if (!v || v < hb_min (0, peak) || v > hb_max (0, peak)) return 0.f;
      else
	scalar *= (float) v / peak;
    }
    return scalar;
  }

  bool           has_peak () const { return tupleIndex & TuppleIndex::EmbeddedPeakTuple; }
  bool   has_intermediate () const { return tupleIndex & TuppleIndex::IntermediateRegion; }
  bool has_private_points () const { return tupleIndex & TuppleIndex::PrivatePointNumbers; }
  unsigned      get_index () const { return tupleIndex & TuppleIndex::TupleIndexMask; }

  protected:
  struct TuppleIndex : HBUINT16
  {
    enum Flags {
      EmbeddedPeakTuple   = 0x8000u,
      IntermediateRegion  = 0x4000u,
      PrivatePointNumbers = 0x2000u,
      TupleIndexMask      = 0x0FFFu
    };

    DEFINE_SIZE_STATIC (2);
  };

  hb_array_t<const F2DOT14> get_all_tuples (unsigned axis_count) const
  { return StructAfter<UnsizedArrayOf<F2DOT14>> (tupleIndex).as_array ((has_peak () + has_intermediate () * 2) * axis_count); }
  hb_array_t<const F2DOT14> get_peak_tuple (unsigned axis_count) const
  { return get_all_tuples (axis_count).sub_array (0, axis_count); }
  hb_array_t<const F2DOT14> get_start_tuple (unsigned axis_count) const
  { return get_all_tuples (axis_count).sub_array (has_peak () * axis_count, axis_count); }
  hb_array_t<const F2DOT14> get_end_tuple (unsigned axis_count) const
  { return get_all_tuples (axis_count).sub_array (has_peak () * axis_count + axis_count, axis_count); }

  HBUINT16	varDataSize;	/* The size in bytes of the serialized
				 * data for this tuple variation table. */
  TuppleIndex	tupleIndex;	/* A packed field. The high 4 bits are flags (see below).
				   The low 12 bits are an index into a shared tuple
				   records array. */
  /* UnsizedArrayOf<F2DOT14> peakTuple - optional */
				/* Peak tuple record for this tuple variation table — optional,
				 * determined by flags in the tupleIndex value.
				 *
				 * Note that this must always be included in the 'cvar' table. */
  /* UnsizedArrayOf<F2DOT14> intermediateStartTuple - optional */
				/* Intermediate start tuple record for this tuple variation table — optional,
				   determined by flags in the tupleIndex value. */
  /* UnsizedArrayOf<F2DOT14> intermediateEndTuple - optional */
				/* Intermediate end tuple record for this tuple variation table — optional,
				 * determined by flags in the tupleIndex value. */
  public:
  DEFINE_SIZE_MIN (4);
};

struct GlyphVariationData
{
  const TupleVariationHeader &get_tuple_var_header (void) const
  { return StructAfter<TupleVariationHeader> (data); }

  struct tuple_iterator_t
  {
    void init (hb_bytes_t var_data_bytes_, unsigned int axis_count_)
    {
      var_data_bytes = var_data_bytes_;
      var_data = var_data_bytes_.as<GlyphVariationData> ();
      index = 0;
      axis_count = axis_count_;
      current_tuple = &var_data->get_tuple_var_header ();
      data_offset = 0;
    }

    bool get_shared_indices (hb_vector_t<unsigned int> &shared_indices /* OUT */)
    {
      if (var_data->has_shared_point_numbers ())
      {
	const HBUINT8 *base = &(var_data+var_data->data);
	const HBUINT8 *p = base;
	if (!unpack_points (p, shared_indices, (const HBUINT8 *) (var_data_bytes.arrayZ + var_data_bytes.length))) return false;
	data_offset = p - base;
      }
      return true;
    }

    bool is_valid () const
    {
      return (index < var_data->tupleVarCount.get_count ()) &&
	     var_data_bytes.check_range (current_tuple, TupleVariationHeader::min_size) &&
	     var_data_bytes.check_range (current_tuple, hb_max (current_tuple->get_data_size (), current_tuple->get_size (axis_count))) &&
	     current_tuple->get_size (axis_count);
    }

    bool move_to_next ()
    {
      data_offset += current_tuple->get_data_size ();
      current_tuple = &current_tuple->get_next (axis_count);
      index++;
      return is_valid ();
    }

    const HBUINT8 *get_serialized_data () const
    { return &(var_data+var_data->data) + data_offset; }

    private:
    const GlyphVariationData *var_data;
    unsigned int index;
    unsigned int axis_count;
    unsigned int data_offset;

    public:
    hb_bytes_t var_data_bytes;
    const TupleVariationHeader *current_tuple;
  };

  static bool get_tuple_iterator (hb_bytes_t var_data_bytes, unsigned axis_count,
				  hb_vector_t<unsigned int> &shared_indices /* OUT */,
				  tuple_iterator_t *iterator /* OUT */)
  {
    iterator->init (var_data_bytes, axis_count);
    if (!iterator->get_shared_indices (shared_indices))
      return false;
    return iterator->is_valid ();
  }

  bool has_shared_point_numbers () const { return tupleVarCount.has_shared_point_numbers (); }

  static bool unpack_points (const HBUINT8 *&p /* IN/OUT */,
			     hb_vector_t<unsigned int> &points /* OUT */,
			     const HBUINT8 *end)
  {
    enum packed_point_flag_t
    {
      POINTS_ARE_WORDS     = 0x80,
      POINT_RUN_COUNT_MASK = 0x7F
    };

    if (unlikely (p + 1 > end)) return false;

    uint16_t count = *p++;
    if (count & POINTS_ARE_WORDS)
    {
      if (unlikely (p + 1 > end)) return false;
      count = ((count & POINT_RUN_COUNT_MASK) << 8) | *p++;
    }
    if (unlikely (!points.resize (count))) return false;

    unsigned int n = 0;
    uint16_t i = 0;
    while (i < count)
    {
      if (unlikely (p + 1 > end)) return false;
      uint16_t j;
      uint8_t control = *p++;
      uint16_t run_count = (control & POINT_RUN_COUNT_MASK) + 1;
      if (control & POINTS_ARE_WORDS)
      {
	for (j = 0; j < run_count && i < count; j++, i++)
	{
	  if (unlikely (p + HBUINT16::static_size > end)) return false;
	  n += *(const HBUINT16 *)p;
	  points[i] = n;
	  p += HBUINT16::static_size;
	}
      }
      else
      {
	for (j = 0; j < run_count && i < count; j++, i++)
	{
	  if (unlikely (p + 1 > end)) return false;
	  n += *p++;
	  points[i] = n;
	}
      }
      if (j < run_count) return false;
    }
    return true;
  }

  static bool unpack_deltas (const HBUINT8 *&p /* IN/OUT */,
			     hb_vector_t<int> &deltas /* IN/OUT */,
			     const HBUINT8 *end)
  {
    enum packed_delta_flag_t
    {
      DELTAS_ARE_ZERO      = 0x80,
      DELTAS_ARE_WORDS     = 0x40,
      DELTA_RUN_COUNT_MASK = 0x3F
    };

    unsigned int i = 0;
    unsigned int count = deltas.length;
    while (i < count)
    {
      if (unlikely (p + 1 > end)) return false;
      uint8_t control = *p++;
      unsigned int run_count = (control & DELTA_RUN_COUNT_MASK) + 1;
      unsigned int j;
      if (control & DELTAS_ARE_ZERO)
	for (j = 0; j < run_count && i < count; j++, i++)
	  deltas[i] = 0;
      else if (control & DELTAS_ARE_WORDS)
	for (j = 0; j < run_count && i < count; j++, i++)
	{
	  if (unlikely (p + HBUINT16::static_size > end)) return false;
	  deltas[i] = *(const HBINT16 *) p;
	  p += HBUINT16::static_size;
	}
      else
	for (j = 0; j < run_count && i < count; j++, i++)
	{
	  if (unlikely (p + 1 > end)) return false;
	  deltas[i] = *(const HBINT8 *) p++;
	}
      if (j < run_count)
	return false;
    }
    return true;
  }

  bool has_data () const { return tupleVarCount; }

  protected:
  struct TupleVarCount : HBUINT16
  {
    bool has_shared_point_numbers () const { return ((*this) & SharedPointNumbers); }
    unsigned int get_count () const { return (*this) & CountMask; }

    protected:
    enum Flags
    {
      SharedPointNumbers= 0x8000u,
      CountMask		= 0x0FFFu
    };
    public:
    DEFINE_SIZE_STATIC (2);
  };

  TupleVarCount	tupleVarCount;  /* A packed field. The high 4 bits are flags, and the
				 * low 12 bits are the number of tuple variation tables
				 * for this glyph. The number of tuple variation tables
				 * can be any number between 1 and 4095. */
  Offset16To<HBUINT8>
		data;		/* Offset from the start of the GlyphVariationData table
				 * to the serialized data. */
  /* TupleVariationHeader tupleVariationHeaders[] *//* Array of tuple variation headers. */
  public:
  DEFINE_SIZE_MIN (4);
};

struct gvar
{
  static constexpr hb_tag_t tableTag = HB_OT_TAG_gvar;

  bool sanitize_shallow (hb_sanitize_context_t *c) const
  {
    TRACE_SANITIZE (this);
    return_trace (c->check_struct (this) && (version.major == 1) &&
		  sharedTuples.sanitize (c, this, axisCount * sharedTupleCount) &&
		  (is_long_offset () ?
		     c->check_array (get_long_offset_array (), glyphCount+1) :
		     c->check_array (get_short_offset_array (), glyphCount+1)));
  }

  /* GlyphVariationData not sanitized here; must be checked while accessing each glyph variation data */
  bool sanitize (hb_sanitize_context_t *c) const
  { return sanitize_shallow (c); }

  bool subset (hb_subset_context_t *c) const
  {
    TRACE_SUBSET (this);

    gvar *out = c->serializer->allocate_min<gvar> ();
    if (unlikely (!out)) return_trace (false);

    out->version.major = 1;
    out->version.minor = 0;
    out->axisCount = axisCount;
    out->sharedTupleCount = sharedTupleCount;

    unsigned int num_glyphs = c->plan->num_output_glyphs ();
    out->glyphCount = num_glyphs;

    unsigned int subset_data_size = 0;
    for (hb_codepoint_t gid = (c->plan->flags & HB_SUBSET_FLAGS_NOTDEF_OUTLINE) ? 0 : 1;
         gid < num_glyphs;
         gid++)
    {
      hb_codepoint_t old_gid;
      if (!c->plan->old_gid_for_new_gid (gid, &old_gid)) continue;
      subset_data_size += get_glyph_var_data_bytes (c->source_blob, old_gid).length;
    }

    bool long_offset = subset_data_size & ~0xFFFFu;
    out->flags = long_offset ? 1 : 0;

    HBUINT8 *subset_offsets = c->serializer->allocate_size<HBUINT8> ((long_offset ? 4 : 2) * (num_glyphs + 1));
    if (!subset_offsets) return_trace (false);

    /* shared tuples */
    if (!sharedTupleCount || !sharedTuples)
      out->sharedTuples = 0;
    else
    {
      unsigned int shared_tuple_size = F2DOT14::static_size * axisCount * sharedTupleCount;
      F2DOT14 *tuples = c->serializer->allocate_size<F2DOT14> (shared_tuple_size);
      if (!tuples) return_trace (false);
      out->sharedTuples = (char *) tuples - (char *) out;
      memcpy (tuples, this+sharedTuples, shared_tuple_size);
    }

    char *subset_data = c->serializer->allocate_size<char> (subset_data_size);
    if (!subset_data) return_trace (false);
    out->dataZ = subset_data - (char *) out;

    unsigned int glyph_offset = 0;
    for (hb_codepoint_t gid = (c->plan->flags & HB_SUBSET_FLAGS_NOTDEF_OUTLINE) ? 0 : 1;
         gid < num_glyphs;
         gid++)
    {
      hb_codepoint_t old_gid;
      hb_bytes_t var_data_bytes = c->plan->old_gid_for_new_gid (gid, &old_gid)
				? get_glyph_var_data_bytes (c->source_blob, old_gid)
				: hb_bytes_t ();

      if (long_offset)
	((HBUINT32 *) subset_offsets)[gid] = glyph_offset;
      else
	((HBUINT16 *) subset_offsets)[gid] = glyph_offset / 2;

      if (var_data_bytes.length > 0)
	memcpy (subset_data, var_data_bytes.arrayZ, var_data_bytes.length);
      subset_data += var_data_bytes.length;
      glyph_offset += var_data_bytes.length;
    }
    if (long_offset)
      ((HBUINT32 *) subset_offsets)[num_glyphs] = glyph_offset;
    else
      ((HBUINT16 *) subset_offsets)[num_glyphs] = glyph_offset / 2;

    return_trace (true);
  }

  protected:
  const hb_bytes_t get_glyph_var_data_bytes (hb_blob_t *blob, hb_codepoint_t glyph) const
  {
    unsigned start_offset = get_offset (glyph);
    unsigned end_offset = get_offset (glyph+1);
    if (unlikely (end_offset < start_offset)) return hb_bytes_t ();
    unsigned length = end_offset - start_offset;
    hb_bytes_t var_data = blob->as_bytes ().sub_array (((unsigned) dataZ) + start_offset, length);
    return likely (var_data.length >= GlyphVariationData::min_size) ? var_data : hb_bytes_t ();
  }

  bool is_long_offset () const { return flags & 1; }

  unsigned get_offset (unsigned i) const
  {
    if (unlikely (i > glyphCount)) return 0;
    return is_long_offset () ? get_long_offset_array ()[i] : get_short_offset_array ()[i] * 2;
  }

  const HBUINT32 * get_long_offset_array () const { return (const HBUINT32 *) &offsetZ; }
  const HBUINT16 *get_short_offset_array () const { return (const HBUINT16 *) &offsetZ; }

  public:
  struct accelerator_t
  {
    accelerator_t (hb_face_t *face)
    { table = hb_sanitize_context_t ().reference_table<gvar> (face); }
    ~accelerator_t () { table.destroy (); }

    private:

    static float infer_delta (const hb_array_t<contour_point_t> points,
			      const hb_array_t<contour_point_t> deltas,
			      unsigned int target, unsigned int prev, unsigned int next,
			      float contour_point_t::*m)
    {
      float target_val = points[target].*m;
      float prev_val = points[prev].*m;
      float next_val = points[next].*m;
      float prev_delta =  deltas[prev].*m;
      float next_delta =  deltas[next].*m;

      if (prev_val == next_val)
	return (prev_delta == next_delta) ? prev_delta : 0.f;
      else if (target_val <= hb_min (prev_val, next_val))
	return (prev_val < next_val) ? prev_delta : next_delta;
      else if (target_val >= hb_max (prev_val, next_val))
	return (prev_val > next_val) ? prev_delta : next_delta;

      /* linear interpolation */
      float r = (target_val - prev_val) / (next_val - prev_val);
      return prev_delta + r * (next_delta - prev_delta);
    }

    static unsigned int next_index (unsigned int i, unsigned int start, unsigned int end)
    { return (i >= end) ? start : (i + 1); }

    public:
    bool apply_deltas_to_points (hb_codepoint_t glyph, hb_font_t *font,
				 const hb_array_t<contour_point_t> points) const
    {
      if (!font->num_coords) return true;

      if (unlikely (glyph >= table->glyphCount)) return true;

      hb_bytes_t var_data_bytes = table->get_glyph_var_data_bytes (table.get_blob (), glyph);
      if (!var_data_bytes.as<GlyphVariationData> ()->has_data ()) return true;
      hb_vector_t<unsigned int> shared_indices;
      GlyphVariationData::tuple_iterator_t iterator;
      if (!GlyphVariationData::get_tuple_iterator (var_data_bytes, table->axisCount,
						   shared_indices, &iterator))
	return true; /* so isn't applied at all */

      /* Save original points for inferred delta calculation */
      contour_point_vector_t orig_points;
      if (unlikely (!orig_points.resize (points.length))) return false;
      for (unsigned int i = 0; i < orig_points.length; i++)
	orig_points.arrayZ[i] = points.arrayZ[i];

      contour_point_vector_t deltas; /* flag is used to indicate referenced point */
      if (unlikely (!deltas.resize (points.length))) return false;

      hb_vector_t<unsigned> end_points;
      for (unsigned i = 0; i < points.length; ++i)
	if (points[i].is_end_point)
	  end_points.push (i);

      auto coords = hb_array (font->coords, font->num_coords);
      unsigned num_coords = table->axisCount;
      hb_array_t<const F2DOT14> shared_tuples = (table+table->sharedTuples).as_array (table->sharedTupleCount * table->axisCount);

      hb_vector_t<unsigned int> private_indices;
      hb_vector_t<int> x_deltas;
      hb_vector_t<int> y_deltas;
      do
      {
	float scalar = iterator.current_tuple->calculate_scalar (coords, num_coords, shared_tuples);
	if (scalar == 0.f) continue;
	const HBUINT8 *p = iterator.get_serialized_data ();
	unsigned int length = iterator.current_tuple->get_data_size ();
	if (unlikely (!iterator.var_data_bytes.check_range (p, length)))
	  return false;

	const HBUINT8 *end = p + length;

	bool has_private_points = iterator.current_tuple->has_private_points ();
	if (has_private_points &&
	    !GlyphVariationData::unpack_points (p, private_indices, end))
	  return false;
	const hb_array_t<unsigned int> &indices = has_private_points ? private_indices : shared_indices;

	bool apply_to_all = (indices.length == 0);
	unsigned int num_deltas = apply_to_all ? points.length : indices.length;
	if (unlikely (!x_deltas.resize (num_deltas))) return false;
	if (unlikely (!GlyphVariationData::unpack_deltas (p, x_deltas, end))) return false;
	if (unlikely (!y_deltas.resize (num_deltas))) return false;
	if (unlikely (!GlyphVariationData::unpack_deltas (p, y_deltas, end))) return false;

	for (unsigned int i = 0; i < deltas.length; i++)
	  deltas[i].init ();
	for (unsigned int i = 0; i < num_deltas; i++)
	{
	  unsigned int pt_index = apply_to_all ? i : indices[i];
	  if (unlikely (pt_index >= deltas.length)) continue;
	  deltas.arrayZ[pt_index].flag = 1;	/* this point is referenced, i.e., explicit deltas specified */
	  deltas.arrayZ[pt_index].x += x_deltas.arrayZ[i] * scalar;
	  deltas.arrayZ[pt_index].y += y_deltas.arrayZ[i] * scalar;
	}

	/* infer deltas for unreferenced points */
	unsigned start_point = 0;
	for (unsigned c = 0; c < end_points.length; c++)
	{
	  unsigned end_point = end_points[c];

	  /* Check the number of unreferenced points in a contour. If no unref points or no ref points, nothing to do. */
	  unsigned unref_count = 0;
	  for (unsigned i = start_point; i <= end_point; i++)
	    if (!deltas[i].flag) unref_count++;

	  unsigned j = start_point;
	  if (unref_count == 0 || unref_count > end_point - start_point)
	    goto no_more_gaps;

	  for (;;)
	  {
	    /* Locate the next gap of unreferenced points between two referenced points prev and next.
	     * Note that a gap may wrap around at left (start_point) and/or at right (end_point).
	     */
	    unsigned int prev, next, i;
	    for (;;)
	    {
	      i = j;
	      j = next_index (i, start_point, end_point);
	      if (deltas[i].flag && !deltas[j].flag) break;
	    }
	    prev = j = i;
	    for (;;)
	    {
	      i = j;
	      j = next_index (i, start_point, end_point);
	      if (!deltas[i].flag && deltas[j].flag) break;
	    }
	    next = j;
	    /* Infer deltas for all unref points in the gap between prev and next */
	    i = prev;
	    for (;;)
	    {
	      i = next_index (i, start_point, end_point);
	      if (i == next) break;
	      deltas[i].x = infer_delta (orig_points.as_array (), deltas.as_array (), i, prev, next, &contour_point_t::x);
	      deltas[i].y = infer_delta (orig_points.as_array (), deltas.as_array (), i, prev, next, &contour_point_t::y);
	      if (--unref_count == 0) goto no_more_gaps;
	    }
	  }
	no_more_gaps:
	  start_point = end_point + 1;
	}

	/* apply specified / inferred deltas to points */
	for (unsigned int i = 0; i < points.length; i++)
	{
	  points.arrayZ[i].x += deltas.arrayZ[i].x;
	  points.arrayZ[i].y += deltas.arrayZ[i].y;
	}
      } while (iterator.move_to_next ());

      return true;
    }

    unsigned int get_axis_count () const { return table->axisCount; }

    private:
    hb_blob_ptr_t<gvar> table;
  };

  protected:
  FixedVersion<>version;	/* Version number of the glyph variations table
				 * Set to 0x00010000u. */
  HBUINT16	axisCount;	/* The number of variation axes for this font. This must be
				 * the same number as axisCount in the 'fvar' table. */
  HBUINT16	sharedTupleCount;
				/* The number of shared tuple records. Shared tuple records
				 * can be referenced within glyph variation data tables for
				 * multiple glyphs, as opposed to other tuple records stored
				 * directly within a glyph variation data table. */
  NNOffset32To<UnsizedArrayOf<F2DOT14>>
		sharedTuples;	/* Offset from the start of this table to the shared tuple records.
				 * Array of tuple records shared across all glyph variation data tables. */
  HBUINT16	glyphCount;	/* The number of glyphs in this font. This must match the number of
				 * glyphs stored elsewhere in the font. */
  HBUINT16	flags;		/* Bit-field that gives the format of the offset array that follows.
				 * If bit 0 is clear, the offsets are uint16; if bit 0 is set, the
				 * offsets are uint32. */
  Offset32To<GlyphVariationData>
		dataZ;		/* Offset from the start of this table to the array of
				 * GlyphVariationData tables. */
  UnsizedArrayOf<HBUINT8>
		offsetZ;	/* Offsets from the start of the GlyphVariationData array
				 * to each GlyphVariationData table. */
  public:
  DEFINE_SIZE_ARRAY (20, offsetZ);
};

struct gvar_accelerator_t : gvar::accelerator_t {
  gvar_accelerator_t (hb_face_t *face) : gvar::accelerator_t (face) {}
};

} /* namespace OT */

#endif /* HB_OT_VAR_GVAR_TABLE_HH */