hb-ot-shaper-myanmar.cc (10808B)
1 /* 2 * Copyright © 2011,2012,2013 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-myanmar-machine.hh" 32 #include "hb-ot-shaper-indic.hh" 33 #include "hb-ot-layout.hh" 34 35 36 /* 37 * Myanmar shaper. 38 */ 39 40 41 static const hb_tag_t 42 myanmar_basic_features[] = 43 { 44 /* 45 * Basic features. 46 * These features are applied in order, one at a time, after reordering, 47 * constrained to the syllable. 48 */ 49 HB_TAG('r','p','h','f'), 50 HB_TAG('p','r','e','f'), 51 HB_TAG('b','l','w','f'), 52 HB_TAG('p','s','t','f'), 53 }; 54 static const hb_tag_t 55 myanmar_other_features[] = 56 { 57 /* 58 * Other features. 59 * These features are applied all at once, after clearing syllables. 60 */ 61 HB_TAG('p','r','e','s'), 62 HB_TAG('a','b','v','s'), 63 HB_TAG('b','l','w','s'), 64 HB_TAG('p','s','t','s'), 65 }; 66 67 static inline void 68 set_myanmar_properties (hb_glyph_info_t &info) 69 { 70 hb_codepoint_t u = info.codepoint; 71 unsigned int type = hb_indic_get_categories (u); 72 73 info.myanmar_category() = (myanmar_category_t) (type & 0xFFu); 74 } 75 76 77 static inline bool 78 is_one_of_myanmar (const hb_glyph_info_t &info, unsigned int flags) 79 { 80 /* If it ligated, all bets are off. */ 81 if (_hb_glyph_info_ligated (&info)) return false; 82 return !!(FLAG_UNSAFE (info.myanmar_category()) & flags); 83 } 84 85 /* Note: 86 * 87 * We treat Vowels and placeholders as if they were consonants. This is safe because Vowels 88 * cannot happen in a consonant syllable. The plus side however is, we can call the 89 * consonant syllable logic from the vowel syllable function and get it all right! 90 * 91 * Keep in sync with consonant_categories in the generator. */ 92 #define CONSONANT_FLAGS_MYANMAR (FLAG (M_Cat(C)) | FLAG (M_Cat(CS)) | FLAG (M_Cat(Ra)) | /* FLAG (M_Cat(CM)) | */ FLAG (M_Cat(IV)) | FLAG (M_Cat(GB)) | FLAG (M_Cat(DOTTEDCIRCLE))) 93 94 static inline bool 95 is_consonant_myanmar (const hb_glyph_info_t &info) 96 { 97 return is_one_of_myanmar (info, CONSONANT_FLAGS_MYANMAR); 98 } 99 100 101 static bool 102 setup_syllables_myanmar (const hb_ot_shape_plan_t *plan, 103 hb_font_t *font, 104 hb_buffer_t *buffer); 105 static bool 106 reorder_myanmar (const hb_ot_shape_plan_t *plan, 107 hb_font_t *font, 108 hb_buffer_t *buffer); 109 110 static void 111 collect_features_myanmar (hb_ot_shape_planner_t *plan) 112 { 113 hb_ot_map_builder_t *map = &plan->map; 114 115 /* Do this before any lookups have been applied. */ 116 map->add_gsub_pause (setup_syllables_myanmar); 117 118 map->enable_feature (HB_TAG('l','o','c','l'), F_PER_SYLLABLE); 119 /* The Indic specs do not require ccmp, but we apply it here since if 120 * there is a use of it, it's typically at the beginning. */ 121 map->enable_feature (HB_TAG('c','c','m','p'), F_PER_SYLLABLE); 122 123 124 map->add_gsub_pause (reorder_myanmar); 125 126 for (unsigned int i = 0; i < ARRAY_LENGTH (myanmar_basic_features); i++) 127 { 128 map->enable_feature (myanmar_basic_features[i], F_MANUAL_ZWJ | F_PER_SYLLABLE); 129 map->add_gsub_pause (nullptr); 130 } 131 map->add_gsub_pause (hb_syllabic_clear_var); // Don't need syllables anymore, use stop to free buffer var 132 133 for (unsigned int i = 0; i < ARRAY_LENGTH (myanmar_other_features); i++) 134 map->enable_feature (myanmar_other_features[i], F_MANUAL_ZWJ); 135 } 136 137 static void 138 setup_masks_myanmar (const hb_ot_shape_plan_t *plan HB_UNUSED, 139 hb_buffer_t *buffer, 140 hb_font_t *font HB_UNUSED) 141 { 142 HB_BUFFER_ALLOCATE_VAR (buffer, myanmar_category); 143 HB_BUFFER_ALLOCATE_VAR (buffer, myanmar_position); 144 145 /* No masks, we just save information about characters. */ 146 147 unsigned int count = buffer->len; 148 hb_glyph_info_t *info = buffer->info; 149 for (unsigned int i = 0; i < count; i++) 150 set_myanmar_properties (info[i]); 151 } 152 153 static bool 154 setup_syllables_myanmar (const hb_ot_shape_plan_t *plan HB_UNUSED, 155 hb_font_t *font HB_UNUSED, 156 hb_buffer_t *buffer) 157 { 158 HB_BUFFER_ALLOCATE_VAR (buffer, syllable); 159 find_syllables_myanmar (buffer); 160 foreach_syllable (buffer, start, end) 161 buffer->unsafe_to_break (start, end); 162 return false; 163 } 164 165 static int 166 compare_myanmar_order (const hb_glyph_info_t *pa, const hb_glyph_info_t *pb) 167 { 168 int a = pa->myanmar_position(); 169 int b = pb->myanmar_position(); 170 171 return (int) a - (int) b; 172 } 173 174 175 /* Rules from: 176 * https://docs.microsoft.com/en-us/typography/script-development/myanmar */ 177 178 static void 179 initial_reordering_consonant_syllable (hb_buffer_t *buffer, 180 unsigned int start, unsigned int end) 181 { 182 hb_glyph_info_t *info = buffer->info; 183 184 unsigned int base = end; 185 bool has_reph = false; 186 187 { 188 unsigned int limit = start; 189 if (start + 3 <= end && 190 info[start ].myanmar_category() == M_Cat(Ra) && 191 info[start+1].myanmar_category() == M_Cat(As) && 192 info[start+2].myanmar_category() == M_Cat(H)) 193 { 194 limit += 3; 195 base = start; 196 has_reph = true; 197 } 198 199 { 200 if (!has_reph) 201 base = limit; 202 203 for (unsigned int i = limit; i < end; i++) 204 if (is_consonant_myanmar (info[i])) 205 { 206 base = i; 207 break; 208 } 209 } 210 } 211 212 /* Reorder! */ 213 { 214 unsigned int i = start; 215 for (; i < start + (has_reph ? 3 : 0); i++) 216 info[i].myanmar_position() = POS_AFTER_MAIN; 217 for (; i < base; i++) 218 info[i].myanmar_position() = POS_PRE_C; 219 if (i < end) 220 { 221 info[i].myanmar_position() = POS_BASE_C; 222 i++; 223 } 224 myanmar_position_t pos = POS_AFTER_MAIN; 225 /* The following loop may be ugly, but it implements all of 226 * Myanmar reordering! */ 227 for (; i < end; i++) 228 { 229 if (info[i].myanmar_category() == M_Cat(MR)) /* Pre-base reordering */ 230 { 231 info[i].myanmar_position() = POS_PRE_C; 232 continue; 233 } 234 if (info[i].myanmar_category() == M_Cat(VPre)) /* Left matra */ 235 { 236 info[i].myanmar_position() = POS_PRE_M; 237 continue; 238 } 239 if (info[i].myanmar_category() == M_Cat(VS)) 240 { 241 info[i].myanmar_position() = info[i - 1].myanmar_position(); 242 continue; 243 } 244 245 if (pos == POS_AFTER_MAIN && info[i].myanmar_category() == M_Cat(VBlw)) 246 { 247 pos = POS_BELOW_C; 248 info[i].myanmar_position() = pos; 249 continue; 250 } 251 252 if (pos == POS_BELOW_C && info[i].myanmar_category() == M_Cat(A)) 253 { 254 info[i].myanmar_position() = POS_BEFORE_SUB; 255 continue; 256 } 257 if (pos == POS_BELOW_C && info[i].myanmar_category() == M_Cat(VBlw)) 258 { 259 info[i].myanmar_position() = pos; 260 continue; 261 } 262 if (pos == POS_BELOW_C && info[i].myanmar_category() != M_Cat(A)) 263 { 264 pos = POS_AFTER_SUB; 265 info[i].myanmar_position() = pos; 266 continue; 267 } 268 info[i].myanmar_position() = pos; 269 } 270 } 271 272 /* Sit tight, rock 'n roll! */ 273 buffer->sort (start, end, compare_myanmar_order); 274 275 /* Flip left-matra sequence. */ 276 unsigned first_left_matra = end; 277 unsigned last_left_matra = end; 278 for (unsigned int i = start; i < end; i++) 279 { 280 if (info[i].myanmar_position() == POS_PRE_M) 281 { 282 if (first_left_matra == end) 283 first_left_matra = i; 284 last_left_matra = i; 285 } 286 } 287 /* https://github.com/harfbuzz/harfbuzz/issues/3863 */ 288 if (first_left_matra < last_left_matra) 289 { 290 /* No need to merge clusters, done already? */ 291 buffer->reverse_range (first_left_matra, last_left_matra + 1); 292 /* Reverse back VS, etc. */ 293 unsigned i = first_left_matra; 294 for (unsigned j = i; j <= last_left_matra; j++) 295 if (info[j].myanmar_category() == M_Cat(VPre)) 296 { 297 buffer->reverse_range (i, j + 1); 298 i = j + 1; 299 } 300 } 301 } 302 303 static void 304 reorder_syllable_myanmar (const hb_ot_shape_plan_t *plan HB_UNUSED, 305 hb_face_t *face HB_UNUSED, 306 hb_buffer_t *buffer, 307 unsigned int start, unsigned int end) 308 { 309 myanmar_syllable_type_t syllable_type = (myanmar_syllable_type_t) (buffer->info[start].syllable() & 0x0F); 310 switch (syllable_type) { 311 312 case myanmar_broken_cluster: /* We already inserted dotted-circles, so just call the consonant_syllable. */ 313 case myanmar_consonant_syllable: 314 initial_reordering_consonant_syllable (buffer, start, end); 315 break; 316 317 case myanmar_non_myanmar_cluster: 318 break; 319 } 320 } 321 322 static bool 323 reorder_myanmar (const hb_ot_shape_plan_t *plan, 324 hb_font_t *font, 325 hb_buffer_t *buffer) 326 { 327 bool ret = false; 328 if (buffer->message (font, "start reordering myanmar")) 329 { 330 if (hb_syllabic_insert_dotted_circles (font, buffer, 331 myanmar_broken_cluster, 332 M_Cat(DOTTEDCIRCLE))) 333 ret = true; 334 335 foreach_syllable (buffer, start, end) 336 reorder_syllable_myanmar (plan, font->face, buffer, start, end); 337 (void) buffer->message (font, "end reordering myanmar"); 338 } 339 340 HB_BUFFER_DEALLOCATE_VAR (buffer, myanmar_category); 341 HB_BUFFER_DEALLOCATE_VAR (buffer, myanmar_position); 342 343 return ret; 344 } 345 346 347 const hb_ot_shaper_t _hb_ot_shaper_myanmar = 348 { 349 collect_features_myanmar, 350 nullptr, /* override_features */ 351 nullptr, /* data_create */ 352 nullptr, /* data_destroy */ 353 nullptr, /* preprocess_text */ 354 nullptr, /* postprocess_glyphs */ 355 nullptr, /* decompose */ 356 nullptr, /* compose */ 357 setup_masks_myanmar, 358 nullptr, /* reorder_marks */ 359 HB_TAG_NONE, /* gpos_tag */ 360 HB_OT_SHAPE_NORMALIZATION_MODE_COMPOSED_DIACRITICS_NO_SHORT_CIRCUIT, 361 HB_OT_SHAPE_ZERO_WIDTH_MARKS_BY_GDEF_EARLY, 362 false, /* fallback_position */ 363 }; 364 365 366 #ifndef HB_NO_OT_SHAPER_MYANMAR_ZAWGYI 367 /* Ugly Zawgyi encoding. 368 * Disable all auto processing. 369 * https://github.com/harfbuzz/harfbuzz/issues/1162 */ 370 const hb_ot_shaper_t _hb_ot_shaper_myanmar_zawgyi = 371 { 372 nullptr, /* collect_features */ 373 nullptr, /* override_features */ 374 nullptr, /* data_create */ 375 nullptr, /* data_destroy */ 376 nullptr, /* preprocess_text */ 377 nullptr, /* postprocess_glyphs */ 378 nullptr, /* decompose */ 379 nullptr, /* compose */ 380 nullptr, /* setup_masks */ 381 nullptr, /* reorder_marks */ 382 HB_TAG_NONE, /* gpos_tag */ 383 HB_OT_SHAPE_NORMALIZATION_MODE_NONE, 384 HB_OT_SHAPE_ZERO_WIDTH_MARKS_NONE, 385 false, /* fallback_position */ 386 }; 387 #endif 388 389 390 #endif