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comparison mupdf-source/thirdparty/harfbuzz/src/hb-ot-shaper-khmer.cc @ 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
25 */
26
27 #include "hb.hh"
28
29 #ifndef HB_NO_OT_SHAPE
30
31 #include "hb-ot-shaper-khmer-machine.hh"
32 #include "hb-ot-shaper-indic.hh"
33 #include "hb-ot-layout.hh"
34
35
36 /*
37 * Khmer shaper.
38 */
39
40
41 static const hb_ot_map_feature_t
42 khmer_features[] =
43 {
44 /*
45 * Basic features.
46 * These features are applied all at once, before reordering, constrained
47 * to the syllable.
48 */
49 {HB_TAG('p','r','e','f'), F_MANUAL_JOINERS | F_PER_SYLLABLE},
50 {HB_TAG('b','l','w','f'), F_MANUAL_JOINERS | F_PER_SYLLABLE},
51 {HB_TAG('a','b','v','f'), F_MANUAL_JOINERS | F_PER_SYLLABLE},
52 {HB_TAG('p','s','t','f'), F_MANUAL_JOINERS | F_PER_SYLLABLE},
53 {HB_TAG('c','f','a','r'), F_MANUAL_JOINERS | F_PER_SYLLABLE},
54 /*
55 * Other features.
56 * These features are applied all at once after clearing syllables.
57 */
58 {HB_TAG('p','r','e','s'), F_GLOBAL_MANUAL_JOINERS},
59 {HB_TAG('a','b','v','s'), F_GLOBAL_MANUAL_JOINERS},
60 {HB_TAG('b','l','w','s'), F_GLOBAL_MANUAL_JOINERS},
61 {HB_TAG('p','s','t','s'), F_GLOBAL_MANUAL_JOINERS},
62 };
63
64 /*
65 * Must be in the same order as the khmer_features array.
66 */
67 enum {
68 KHMER_PREF,
69 KHMER_BLWF,
70 KHMER_ABVF,
71 KHMER_PSTF,
72 KHMER_CFAR,
73
74 _KHMER_PRES,
75 _KHMER_ABVS,
76 _KHMER_BLWS,
77 _KHMER_PSTS,
78
79 KHMER_NUM_FEATURES,
80 KHMER_BASIC_FEATURES = _KHMER_PRES, /* Don't forget to update this! */
81 };
82
83 static inline void
84 set_khmer_properties (hb_glyph_info_t &info)
85 {
86 hb_codepoint_t u = info.codepoint;
87 unsigned int type = hb_indic_get_categories (u);
88
89 info.khmer_category() = (khmer_category_t) (type & 0xFFu);
90 }
91
92 static bool
93 setup_syllables_khmer (const hb_ot_shape_plan_t *plan,
94 hb_font_t *font,
95 hb_buffer_t *buffer);
96 static bool
97 reorder_khmer (const hb_ot_shape_plan_t *plan,
98 hb_font_t *font,
99 hb_buffer_t *buffer);
100
101 static void
102 collect_features_khmer (hb_ot_shape_planner_t *plan)
103 {
104 hb_ot_map_builder_t *map = &plan->map;
105
106 /* Do this before any lookups have been applied. */
107 map->add_gsub_pause (setup_syllables_khmer);
108 map->add_gsub_pause (reorder_khmer);
109
110 /* Testing suggests that Uniscribe does NOT pause between basic
111 * features. Test with KhmerUI.ttf and the following three
112 * sequences:
113 *
114 * U+1789,U+17BC
115 * U+1789,U+17D2,U+1789
116 * U+1789,U+17D2,U+1789,U+17BC
117 *
118 * https://github.com/harfbuzz/harfbuzz/issues/974
119 */
120 map->enable_feature (HB_TAG('l','o','c','l'), F_PER_SYLLABLE);
121 map->enable_feature (HB_TAG('c','c','m','p'), F_PER_SYLLABLE);
122
123 unsigned int i = 0;
124 for (; i < KHMER_BASIC_FEATURES; i++)
125 map->add_feature (khmer_features[i]);
126
127 /* https://github.com/harfbuzz/harfbuzz/issues/3531 */
128 map->add_gsub_pause (hb_syllabic_clear_var); // Don't need syllables anymore, use stop to free buffer var
129
130 for (; i < KHMER_NUM_FEATURES; i++)
131 map->add_feature (khmer_features[i]);
132 }
133
134 static void
135 override_features_khmer (hb_ot_shape_planner_t *plan)
136 {
137 hb_ot_map_builder_t *map = &plan->map;
138
139 /* Khmer spec has 'clig' as part of required shaping features:
140 * "Apply feature 'clig' to form ligatures that are desired for
141 * typographical correctness.", hence in overrides... */
142 map->enable_feature (HB_TAG('c','l','i','g'));
143
144 /* Uniscribe does not apply 'kern' in Khmer. */
145 if (hb_options ().uniscribe_bug_compatible)
146 {
147 map->disable_feature (HB_TAG('k','e','r','n'));
148 }
149
150 map->disable_feature (HB_TAG('l','i','g','a'));
151 }
152
153
154 struct khmer_shape_plan_t
155 {
156 hb_mask_t mask_array[KHMER_NUM_FEATURES];
157 };
158
159 static void *
160 data_create_khmer (const hb_ot_shape_plan_t *plan)
161 {
162 khmer_shape_plan_t *khmer_plan = (khmer_shape_plan_t *) hb_calloc (1, sizeof (khmer_shape_plan_t));
163 if (unlikely (!khmer_plan))
164 return nullptr;
165
166 for (unsigned int i = 0; i < ARRAY_LENGTH (khmer_plan->mask_array); i++)
167 khmer_plan->mask_array[i] = (khmer_features[i].flags & F_GLOBAL) ?
168 0 : plan->map.get_1_mask (khmer_features[i].tag);
169
170 return khmer_plan;
171 }
172
173 static void
174 data_destroy_khmer (void *data)
175 {
176 hb_free (data);
177 }
178
179 static void
180 setup_masks_khmer (const hb_ot_shape_plan_t *plan HB_UNUSED,
181 hb_buffer_t *buffer,
182 hb_font_t *font HB_UNUSED)
183 {
184 HB_BUFFER_ALLOCATE_VAR (buffer, khmer_category);
185
186 /* We cannot setup masks here. We save information about characters
187 * and setup masks later on in a pause-callback. */
188
189 unsigned int count = buffer->len;
190 hb_glyph_info_t *info = buffer->info;
191 for (unsigned int i = 0; i < count; i++)
192 set_khmer_properties (info[i]);
193 }
194
195 static bool
196 setup_syllables_khmer (const hb_ot_shape_plan_t *plan HB_UNUSED,
197 hb_font_t *font HB_UNUSED,
198 hb_buffer_t *buffer)
199 {
200 HB_BUFFER_ALLOCATE_VAR (buffer, syllable);
201 find_syllables_khmer (buffer);
202 foreach_syllable (buffer, start, end)
203 buffer->unsafe_to_break (start, end);
204 return false;
205 }
206
207
208 /* Rules from:
209 * https://docs.microsoft.com/en-us/typography/script-development/devanagari */
210
211 static void
212 reorder_consonant_syllable (const hb_ot_shape_plan_t *plan,
213 hb_face_t *face HB_UNUSED,
214 hb_buffer_t *buffer,
215 unsigned int start, unsigned int end)
216 {
217 const khmer_shape_plan_t *khmer_plan = (const khmer_shape_plan_t *) plan->data;
218 hb_glyph_info_t *info = buffer->info;
219
220 /* Setup masks. */
221 {
222 /* Post-base */
223 hb_mask_t mask = khmer_plan->mask_array[KHMER_BLWF] |
224 khmer_plan->mask_array[KHMER_ABVF] |
225 khmer_plan->mask_array[KHMER_PSTF];
226 for (unsigned int i = start + 1; i < end; i++)
227 info[i].mask |= mask;
228 }
229
230 unsigned int num_coengs = 0;
231 for (unsigned int i = start + 1; i < end; i++)
232 {
233 /* """
234 * When a COENG + (Cons | IndV) combination are found (and subscript count
235 * is less than two) the character combination is handled according to the
236 * subscript type of the character following the COENG.
237 *
238 * ...
239 *
240 * Subscript Type 2 - The COENG + RO characters are reordered to immediately
241 * before the base glyph. Then the COENG + RO characters are assigned to have
242 * the 'pref' OpenType feature applied to them.
243 * """
244 */
245 if (info[i].khmer_category() == K_Cat(H) && num_coengs <= 2 && i + 1 < end)
246 {
247 num_coengs++;
248
249 if (info[i + 1].khmer_category() == K_Cat(Ra))
250 {
251 for (unsigned int j = 0; j < 2; j++)
252 info[i + j].mask |= khmer_plan->mask_array[KHMER_PREF];
253
254 /* Move the Coeng,Ro sequence to the start. */
255 buffer->merge_clusters (start, i + 2);
256 hb_glyph_info_t t0 = info[i];
257 hb_glyph_info_t t1 = info[i + 1];
258 memmove (&info[start + 2], &info[start], (i - start) * sizeof (info[0]));
259 info[start] = t0;
260 info[start + 1] = t1;
261
262 /* Mark the subsequent stuff with 'cfar'. Used in Khmer.
263 * Read the feature spec.
264 * This allows distinguishing the following cases with MS Khmer fonts:
265 * U+1784,U+17D2,U+179A,U+17D2,U+1782
266 * U+1784,U+17D2,U+1782,U+17D2,U+179A
267 */
268 if (khmer_plan->mask_array[KHMER_CFAR])
269 for (unsigned int j = i + 2; j < end; j++)
270 info[j].mask |= khmer_plan->mask_array[KHMER_CFAR];
271
272 num_coengs = 2; /* Done. */
273 }
274 }
275
276 /* Reorder left matra piece. */
277 else if (info[i].khmer_category() == K_Cat(VPre))
278 {
279 /* Move to the start. */
280 buffer->merge_clusters (start, i + 1);
281 hb_glyph_info_t t = info[i];
282 memmove (&info[start + 1], &info[start], (i - start) * sizeof (info[0]));
283 info[start] = t;
284 }
285 }
286 }
287
288 static void
289 reorder_syllable_khmer (const hb_ot_shape_plan_t *plan,
290 hb_face_t *face,
291 hb_buffer_t *buffer,
292 unsigned int start, unsigned int end)
293 {
294 khmer_syllable_type_t syllable_type = (khmer_syllable_type_t) (buffer->info[start].syllable() & 0x0F);
295 switch (syllable_type)
296 {
297 case khmer_broken_cluster: /* We already inserted dotted-circles, so just call the consonant_syllable. */
298 case khmer_consonant_syllable:
299 reorder_consonant_syllable (plan, face, buffer, start, end);
300 break;
301
302 case khmer_non_khmer_cluster:
303 break;
304 }
305 }
306
307 static bool
308 reorder_khmer (const hb_ot_shape_plan_t *plan,
309 hb_font_t *font,
310 hb_buffer_t *buffer)
311 {
312 bool ret = false;
313 if (buffer->message (font, "start reordering khmer"))
314 {
315 if (hb_syllabic_insert_dotted_circles (font, buffer,
316 khmer_broken_cluster,
317 K_Cat(DOTTEDCIRCLE),
318 (unsigned) -1))
319 ret = true;
320
321 foreach_syllable (buffer, start, end)
322 reorder_syllable_khmer (plan, font->face, buffer, start, end);
323 (void) buffer->message (font, "end reordering khmer");
324 }
325 HB_BUFFER_DEALLOCATE_VAR (buffer, khmer_category);
326
327 return ret;
328 }
329
330
331 static bool
332 decompose_khmer (const hb_ot_shape_normalize_context_t *c,
333 hb_codepoint_t ab,
334 hb_codepoint_t *a,
335 hb_codepoint_t *b)
336 {
337 switch (ab)
338 {
339 /*
340 * Decompose split matras that don't have Unicode decompositions.
341 */
342
343 /* Khmer */
344 case 0x17BEu : *a = 0x17C1u; *b= 0x17BEu; return true;
345 case 0x17BFu : *a = 0x17C1u; *b= 0x17BFu; return true;
346 case 0x17C0u : *a = 0x17C1u; *b= 0x17C0u; return true;
347 case 0x17C4u : *a = 0x17C1u; *b= 0x17C4u; return true;
348 case 0x17C5u : *a = 0x17C1u; *b= 0x17C5u; return true;
349 }
350
351 return (bool) c->unicode->decompose (ab, a, b);
352 }
353
354 static bool
355 compose_khmer (const hb_ot_shape_normalize_context_t *c,
356 hb_codepoint_t a,
357 hb_codepoint_t b,
358 hb_codepoint_t *ab)
359 {
360 /* Avoid recomposing split matras. */
361 if (HB_UNICODE_GENERAL_CATEGORY_IS_MARK (c->unicode->general_category (a)))
362 return false;
363
364 return (bool) c->unicode->compose (a, b, ab);
365 }
366
367
368 const hb_ot_shaper_t _hb_ot_shaper_khmer =
369 {
370 collect_features_khmer,
371 override_features_khmer,
372 data_create_khmer,
373 data_destroy_khmer,
374 nullptr, /* preprocess_text */
375 nullptr, /* postprocess_glyphs */
376 decompose_khmer,
377 compose_khmer,
378 setup_masks_khmer,
379 nullptr, /* reorder_marks */
380 HB_TAG_NONE, /* gpos_tag */
381 HB_OT_SHAPE_NORMALIZATION_MODE_COMPOSED_DIACRITICS_NO_SHORT_CIRCUIT,
382 HB_OT_SHAPE_ZERO_WIDTH_MARKS_NONE,
383 false, /* fallback_position */
384 };
385
386
387 #endif