1#ifndef OT_LAYOUT_GPOS_PAIRPOSFORMAT2_HH
2#define OT_LAYOUT_GPOS_PAIRPOSFORMAT2_HH
3
4#include "ValueFormat.hh"
5
6namespace OT {
7namespace Layout {
8namespace GPOS_impl {
9
10template <typename Types>
11struct PairPosFormat2_4
12{
13 protected:
14 HBUINT16 format; /* Format identifier--format = 2 */
15 typename Types::template OffsetTo<Coverage>
16 coverage; /* Offset to Coverage table--from
17 * beginning of subtable */
18 ValueFormat valueFormat1; /* ValueRecord definition--for the
19 * first glyph of the pair--may be zero
20 * (0) */
21 ValueFormat valueFormat2; /* ValueRecord definition--for the
22 * second glyph of the pair--may be
23 * zero (0) */
24 typename Types::template OffsetTo<ClassDef>
25 classDef1; /* Offset to ClassDef table--from
26 * beginning of PairPos subtable--for
27 * the first glyph of the pair */
28 typename Types::template OffsetTo<ClassDef>
29 classDef2; /* Offset to ClassDef table--from
30 * beginning of PairPos subtable--for
31 * the second glyph of the pair */
32 HBUINT16 class1Count; /* Number of classes in ClassDef1
33 * table--includes Class0 */
34 HBUINT16 class2Count; /* Number of classes in ClassDef2
35 * table--includes Class0 */
36 ValueRecord values; /* Matrix of value pairs:
37 * class1-major, class2-minor,
38 * Each entry has value1 and value2 */
39 public:
40 DEFINE_SIZE_ARRAY (10 + 3 * Types::size, values);
41
42 bool sanitize (hb_sanitize_context_t *c) const
43 {
44 TRACE_SANITIZE (this);
45 if (!(c->check_struct (this)
46 && coverage.sanitize (c, this)
47 && classDef1.sanitize (c, this)
48 && classDef2.sanitize (c, this))) return_trace (false);
49
50 unsigned int len1 = valueFormat1.get_len ();
51 unsigned int len2 = valueFormat2.get_len ();
52 unsigned int stride = HBUINT16::static_size * (len1 + len2);
53 unsigned int count = (unsigned int) class1Count * (unsigned int) class2Count;
54 return_trace (c->check_range ((const void *) values,
55 count,
56 stride) &&
57 (c->lazy_some_gpos ||
58 (valueFormat1.sanitize_values_stride_unsafe (c, this, &values[0], count, stride) &&
59 valueFormat2.sanitize_values_stride_unsafe (c, this, &values[len1], count, stride))));
60 }
61
62 bool intersects (const hb_set_t *glyphs) const
63 {
64 return (this+coverage).intersects (glyphs) &&
65 (this+classDef2).intersects (glyphs);
66 }
67
68 void closure_lookups (hb_closure_lookups_context_t *c) const {}
69 void collect_variation_indices (hb_collect_variation_indices_context_t *c) const
70 {
71 if (!intersects (c->glyph_set)) return;
72 if ((!valueFormat1.has_device ()) && (!valueFormat2.has_device ())) return;
73
74 hb_set_t klass1_glyphs, klass2_glyphs;
75 if (!(this+classDef1).collect_coverage (&klass1_glyphs)) return;
76 if (!(this+classDef2).collect_coverage (&klass2_glyphs)) return;
77
78 hb_set_t class1_set, class2_set;
79 for (const unsigned cp : + c->glyph_set->iter () | hb_filter (this + coverage))
80 {
81 if (!klass1_glyphs.has (cp)) class1_set.add (0);
82 else
83 {
84 unsigned klass1 = (this+classDef1).get (cp);
85 class1_set.add (klass1);
86 }
87 }
88
89 class2_set.add (0);
90 for (const unsigned cp : + c->glyph_set->iter () | hb_filter (klass2_glyphs))
91 {
92 unsigned klass2 = (this+classDef2).get (cp);
93 class2_set.add (klass2);
94 }
95
96 if (class1_set.is_empty ()
97 || class2_set.is_empty ()
98 || (class2_set.get_population() == 1 && class2_set.has(0)))
99 return;
100
101 unsigned len1 = valueFormat1.get_len ();
102 unsigned len2 = valueFormat2.get_len ();
103 const hb_array_t<const Value> values_array = values.as_array ((unsigned)class1Count * (unsigned) class2Count * (len1 + len2));
104 for (const unsigned class1_idx : class1_set.iter ())
105 {
106 for (const unsigned class2_idx : class2_set.iter ())
107 {
108 unsigned start_offset = (class1_idx * (unsigned) class2Count + class2_idx) * (len1 + len2);
109 if (valueFormat1.has_device ())
110 valueFormat1.collect_variation_indices (c, this, values_array.sub_array (start_offset, len1));
111
112 if (valueFormat2.has_device ())
113 valueFormat2.collect_variation_indices (c, this, values_array.sub_array (start_offset+len1, len2));
114 }
115 }
116 }
117
118 void collect_glyphs (hb_collect_glyphs_context_t *c) const
119 {
120 if (unlikely (!(this+coverage).collect_coverage (c->input))) return;
121 if (unlikely (!(this+classDef2).collect_coverage (c->input))) return;
122 }
123
124 const Coverage &get_coverage () const { return this+coverage; }
125
126 bool apply (hb_ot_apply_context_t *c) const
127 {
128 TRACE_APPLY (this);
129 hb_buffer_t *buffer = c->buffer;
130 unsigned int index = (this+coverage).get_coverage (buffer->cur().codepoint);
131 if (likely (index == NOT_COVERED)) return_trace (false);
132
133 hb_ot_apply_context_t::skipping_iterator_t &skippy_iter = c->iter_input;
134 skippy_iter.reset_fast (buffer->idx);
135 unsigned unsafe_to;
136 if (unlikely (!skippy_iter.next (&unsafe_to)))
137 {
138 buffer->unsafe_to_concat (buffer->idx, unsafe_to);
139 return_trace (false);
140 }
141
142 unsigned int klass2 = (this+classDef2).get_class (buffer->info[skippy_iter.idx].codepoint);
143 if (!klass2)
144 {
145 buffer->unsafe_to_concat (buffer->idx, skippy_iter.idx + 1);
146 return_trace (false);
147 }
148
149 unsigned int klass1 = (this+classDef1).get_class (buffer->cur().codepoint);
150 if (unlikely (klass1 >= class1Count || klass2 >= class2Count))
151 {
152 buffer->unsafe_to_concat (buffer->idx, skippy_iter.idx + 1);
153 return_trace (false);
154 }
155
156 unsigned int len1 = valueFormat1.get_len ();
157 unsigned int len2 = valueFormat2.get_len ();
158 unsigned int record_len = len1 + len2;
159
160 const Value *v = &values[record_len * (klass1 * class2Count + klass2)];
161
162 bool applied_first = false, applied_second = false;
163
164
165 /* Isolate simple kerning and apply it half to each side.
166 * Results in better cursor positinoing / underline drawing.
167 *
168 * Disabled, because causes issues... :-(
169 * https://github.com/harfbuzz/harfbuzz/issues/3408
170 * https://github.com/harfbuzz/harfbuzz/pull/3235#issuecomment-1029814978
171 */
172#ifndef HB_SPLIT_KERN
173 if (false)
174#endif
175 {
176 if (!len2)
177 {
178 const hb_direction_t dir = buffer->props.direction;
179 const bool horizontal = HB_DIRECTION_IS_HORIZONTAL (dir);
180 const bool backward = HB_DIRECTION_IS_BACKWARD (dir);
181 unsigned mask = horizontal ? ValueFormat::xAdvance : ValueFormat::yAdvance;
182 if (backward)
183 mask |= mask >> 2; /* Add eg. xPlacement in RTL. */
184 /* Add Devices. */
185 mask |= mask << 4;
186
187 if (valueFormat1 & ~mask)
188 goto bail;
189
190 /* Is simple kern. Apply value on an empty position slot,
191 * then split it between sides. */
192
193 hb_glyph_position_t pos{};
194 if (valueFormat1.apply_value (c, this, v, pos))
195 {
196 hb_position_t *src = &pos.x_advance;
197 hb_position_t *dst1 = &buffer->cur_pos().x_advance;
198 hb_position_t *dst2 = &buffer->pos[skippy_iter.idx].x_advance;
199 unsigned i = horizontal ? 0 : 1;
200
201 hb_position_t kern = src[i];
202 hb_position_t kern1 = kern >> 1;
203 hb_position_t kern2 = kern - kern1;
204
205 if (!backward)
206 {
207 dst1[i] += kern1;
208 dst2[i] += kern2;
209 dst2[i + 2] += kern2;
210 }
211 else
212 {
213 dst1[i] += kern1;
214 dst1[i + 2] += src[i + 2] - kern2;
215 dst2[i] += kern2;
216 }
217
218 applied_first = applied_second = kern != 0;
219 goto success;
220 }
221 goto boring;
222 }
223 }
224 bail:
225
226 if (HB_BUFFER_MESSAGE_MORE && c->buffer->messaging ())
227 {
228 c->buffer->message (c->font,
229 "try kerning glyphs at %u,%u",
230 c->buffer->idx, skippy_iter.idx);
231 }
232
233 applied_first = len1 && valueFormat1.apply_value (c, this, v, buffer->cur_pos());
234 applied_second = len2 && valueFormat2.apply_value (c, this, v + len1, buffer->pos[skippy_iter.idx]);
235
236 if (applied_first || applied_second)
237 if (HB_BUFFER_MESSAGE_MORE && c->buffer->messaging ())
238 {
239 c->buffer->message (c->font,
240 "kerned glyphs at %u,%u",
241 c->buffer->idx, skippy_iter.idx);
242 }
243
244 if (HB_BUFFER_MESSAGE_MORE && c->buffer->messaging ())
245 {
246 c->buffer->message (c->font,
247 "tried kerning glyphs at %u,%u",
248 c->buffer->idx, skippy_iter.idx);
249 }
250
251 success:
252 if (applied_first || applied_second)
253 buffer->unsafe_to_break (buffer->idx, skippy_iter.idx + 1);
254 else
255 boring:
256 buffer->unsafe_to_concat (buffer->idx, skippy_iter.idx + 1);
257
258 if (len2)
259 {
260 skippy_iter.idx++;
261 // https://github.com/harfbuzz/harfbuzz/issues/3824
262 // https://github.com/harfbuzz/harfbuzz/issues/3888#issuecomment-1326781116
263 buffer->unsafe_to_break (buffer->idx, skippy_iter.idx + 1);
264 }
265
266 buffer->idx = skippy_iter.idx;
267
268 return_trace (true);
269 }
270
271 bool subset (hb_subset_context_t *c) const
272 {
273 TRACE_SUBSET (this);
274 auto *out = c->serializer->start_embed (*this);
275 if (unlikely (!c->serializer->extend_min (out))) return_trace (false);
276 out->format = format;
277
278 hb_map_t klass1_map;
279 out->classDef1.serialize_subset (c, classDef1, this, &klass1_map, true, true, &(this + coverage));
280 out->class1Count = klass1_map.get_population ();
281
282 hb_map_t klass2_map;
283 out->classDef2.serialize_subset (c, classDef2, this, &klass2_map, true, false);
284 out->class2Count = klass2_map.get_population ();
285
286 unsigned len1 = valueFormat1.get_len ();
287 unsigned len2 = valueFormat2.get_len ();
288
289 hb_pair_t<unsigned, unsigned> newFormats = hb_pair (valueFormat1, valueFormat2);
290 if (c->plan->flags & HB_SUBSET_FLAGS_NO_HINTING)
291 newFormats = compute_effective_value_formats (klass1_map, klass2_map);
292
293 out->valueFormat1 = newFormats.first;
294 out->valueFormat2 = newFormats.second;
295
296 if (c->plan->all_axes_pinned)
297 {
298 out->valueFormat1 = out->valueFormat1.drop_device_table_flags ();
299 out->valueFormat2 = out->valueFormat2.drop_device_table_flags ();
300 }
301
302 unsigned total_len = len1 + len2;
303 hb_vector_t<unsigned> class2_idxs (+ hb_range ((unsigned) class2Count) | hb_filter (klass2_map));
304 for (unsigned class1_idx : + hb_range ((unsigned) class1Count) | hb_filter (klass1_map))
305 {
306 for (unsigned class2_idx : class2_idxs)
307 {
308 unsigned idx = (class1_idx * (unsigned) class2Count + class2_idx) * total_len;
309 valueFormat1.copy_values (c->serializer, out->valueFormat1, this, &values[idx], &c->plan->layout_variation_idx_delta_map);
310 valueFormat2.copy_values (c->serializer, out->valueFormat2, this, &values[idx + len1], &c->plan->layout_variation_idx_delta_map);
311 }
312 }
313
314 const hb_set_t &glyphset = *c->plan->glyphset_gsub ();
315 const hb_map_t &glyph_map = *c->plan->glyph_map;
316
317 auto it =
318 + hb_iter (this+coverage)
319 | hb_filter (glyphset)
320 | hb_map_retains_sorting (glyph_map)
321 ;
322
323 out->coverage.serialize_serialize (c->serializer, it);
324 return_trace (out->class1Count && out->class2Count && bool (it));
325 }
326
327
328 hb_pair_t<unsigned, unsigned> compute_effective_value_formats (const hb_map_t& klass1_map,
329 const hb_map_t& klass2_map) const
330 {
331 unsigned len1 = valueFormat1.get_len ();
332 unsigned len2 = valueFormat2.get_len ();
333 unsigned record_size = len1 + len2;
334
335 unsigned format1 = 0;
336 unsigned format2 = 0;
337
338 for (unsigned class1_idx : + hb_range ((unsigned) class1Count) | hb_filter (klass1_map))
339 {
340 for (unsigned class2_idx : + hb_range ((unsigned) class2Count) | hb_filter (klass2_map))
341 {
342 unsigned idx = (class1_idx * (unsigned) class2Count + class2_idx) * record_size;
343 format1 = format1 | valueFormat1.get_effective_format (&values[idx]);
344 format2 = format2 | valueFormat2.get_effective_format (&values[idx + len1]);
345 }
346
347 if (format1 == valueFormat1 && format2 == valueFormat2)
348 break;
349 }
350
351 return hb_pair (format1, format2);
352 }
353};
354
355}
356}
357}
358
359#endif // OT_LAYOUT_GPOS_PAIRPOSFORMAT2_HH
360