1 /* 2 * Copyright 2010,2012 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-ot-shape-complex-private.hh" 28 29 30 /* Thai / Lao shaper */ 31 32 33 /* PUA shaping */ 34 35 36 enum thai_consonant_type_t 37 { 38 NC, 39 AC, 40 RC, 41 DC, 42 NOT_CONSONANT, 43 NUM_CONSONANT_TYPES = NOT_CONSONANT 44 }; 45 46 static thai_consonant_type_t 47 get_consonant_type (hb_codepoint_t u) 48 { 49 if (u == 0x0E1Bu || u == 0x0E1Du || u == 0x0E1Fu/* || u == 0x0E2Cu*/) 50 return AC; 51 if (u == 0x0E0Du || u == 0x0E10u) 52 return RC; 53 if (u == 0x0E0Eu || u == 0x0E0Fu) 54 return DC; 55 if (hb_in_range<hb_codepoint_t> (u, 0x0E01u, 0x0E2Eu)) 56 return NC; 57 return NOT_CONSONANT; 58 } 59 60 61 enum thai_mark_type_t 62 { 63 AV, 64 BV, 65 T, 66 NOT_MARK, 67 NUM_MARK_TYPES = NOT_MARK 68 }; 69 70 static thai_mark_type_t 71 get_mark_type (hb_codepoint_t u) 72 { 73 if (u == 0x0E31u || hb_in_range<hb_codepoint_t> (u, 0x0E34u, 0x0E37u) || 74 u == 0x0E47u || hb_in_range<hb_codepoint_t> (u, 0x0E4Du, 0x0E4Eu)) 75 return AV; 76 if (hb_in_range<hb_codepoint_t> (u, 0x0E38u, 0x0E3Au)) 77 return BV; 78 if (hb_in_range<hb_codepoint_t> (u, 0x0E48u, 0x0E4Cu)) 79 return T; 80 return NOT_MARK; 81 } 82 83 84 enum thai_action_t 85 { 86 NOP, 87 SD, /* Shift combining-mark down */ 88 SL, /* Shift combining-mark left */ 89 SDL, /* Shift combining-mark down-left */ 90 RD /* Remove descender from base */ 91 }; 92 93 static hb_codepoint_t 94 thai_pua_shape (hb_codepoint_t u, thai_action_t action, hb_font_t *font) 95 { 96 struct thai_pua_mapping_t { 97 hb_codepoint_t u; 98 hb_codepoint_t win_pua; 99 hb_codepoint_t mac_pua; 100 } const *pua_mappings = nullptr; 101 static const thai_pua_mapping_t SD_mappings[] = { 102 {0x0E48u, 0xF70Au, 0xF88Bu}, /* MAI EK */ 103 {0x0E49u, 0xF70Bu, 0xF88Eu}, /* MAI THO */ 104 {0x0E4Au, 0xF70Cu, 0xF891u}, /* MAI TRI */ 105 {0x0E4Bu, 0xF70Du, 0xF894u}, /* MAI CHATTAWA */ 106 {0x0E4Cu, 0xF70Eu, 0xF897u}, /* THANTHAKHAT */ 107 {0x0E38u, 0xF718u, 0xF89Bu}, /* SARA U */ 108 {0x0E39u, 0xF719u, 0xF89Cu}, /* SARA UU */ 109 {0x0E3Au, 0xF71Au, 0xF89Du}, /* PHINTHU */ 110 {0x0000u, 0x0000u, 0x0000u} 111 }; 112 static const thai_pua_mapping_t SDL_mappings[] = { 113 {0x0E48u, 0xF705u, 0xF88Cu}, /* MAI EK */ 114 {0x0E49u, 0xF706u, 0xF88Fu}, /* MAI THO */ 115 {0x0E4Au, 0xF707u, 0xF892u}, /* MAI TRI */ 116 {0x0E4Bu, 0xF708u, 0xF895u}, /* MAI CHATTAWA */ 117 {0x0E4Cu, 0xF709u, 0xF898u}, /* THANTHAKHAT */ 118 {0x0000u, 0x0000u, 0x0000u} 119 }; 120 static const thai_pua_mapping_t SL_mappings[] = { 121 {0x0E48u, 0xF713u, 0xF88Au}, /* MAI EK */ 122 {0x0E49u, 0xF714u, 0xF88Du}, /* MAI THO */ 123 {0x0E4Au, 0xF715u, 0xF890u}, /* MAI TRI */ 124 {0x0E4Bu, 0xF716u, 0xF893u}, /* MAI CHATTAWA */ 125 {0x0E4Cu, 0xF717u, 0xF896u}, /* THANTHAKHAT */ 126 {0x0E31u, 0xF710u, 0xF884u}, /* MAI HAN-AKAT */ 127 {0x0E34u, 0xF701u, 0xF885u}, /* SARA I */ 128 {0x0E35u, 0xF702u, 0xF886u}, /* SARA II */ 129 {0x0E36u, 0xF703u, 0xF887u}, /* SARA UE */ 130 {0x0E37u, 0xF704u, 0xF888u}, /* SARA UEE */ 131 {0x0E47u, 0xF712u, 0xF889u}, /* MAITAIKHU */ 132 {0x0E4Du, 0xF711u, 0xF899u}, /* NIKHAHIT */ 133 {0x0000u, 0x0000u, 0x0000u} 134 }; 135 static const thai_pua_mapping_t RD_mappings[] = { 136 {0x0E0Du, 0xF70Fu, 0xF89Au}, /* YO YING */ 137 {0x0E10u, 0xF700u, 0xF89Eu}, /* THO THAN */ 138 {0x0000u, 0x0000u, 0x0000u} 139 }; 140 141 switch (action) { 142 case NOP: return u; 143 case SD: pua_mappings = SD_mappings; break; 144 case SDL: pua_mappings = SDL_mappings; break; 145 case SL: pua_mappings = SL_mappings; break; 146 case RD: pua_mappings = RD_mappings; break; 147 } 148 for (; pua_mappings->u; pua_mappings++) 149 if (pua_mappings->u == u) 150 { 151 hb_codepoint_t glyph; 152 if (hb_font_get_glyph (font, pua_mappings->win_pua, 0, &glyph)) 153 return pua_mappings->win_pua; 154 if (hb_font_get_glyph (font, pua_mappings->mac_pua, 0, &glyph)) 155 return pua_mappings->mac_pua; 156 break; 157 } 158 return u; 159 } 160 161 162 static enum thai_above_state_t 163 { /* Cluster above looks like: */ 164 T0, /* */ 165 T1, /* */ 166 T2, /* */ 167 T3, /* */ 168 NUM_ABOVE_STATES 169 } thai_above_start_state[NUM_CONSONANT_TYPES + 1/* For NOT_CONSONANT */] = 170 { 171 T0, /* NC */ 172 T1, /* AC */ 173 T0, /* RC */ 174 T0, /* DC */ 175 T3, /* NOT_CONSONANT */ 176 }; 177 178 static const struct thai_above_state_machine_edge_t { 179 thai_action_t action; 180 thai_above_state_t next_state; 181 } thai_above_state_machine[NUM_ABOVE_STATES][NUM_MARK_TYPES] = 182 { /*AV*/ /*BV*/ /*T*/ 183 /*T0*/ {{NOP,T3}, {NOP,T0}, {SD, T3}}, 184 /*T1*/ {{SL, T2}, {NOP,T1}, {SDL,T2}}, 185 /*T2*/ {{NOP,T3}, {NOP,T2}, {SL, T3}}, 186 /*T3*/ {{NOP,T3}, {NOP,T3}, {NOP,T3}}, 187 }; 188 189 190 static enum thai_below_state_t 191 { 192 B0, /* No descender */ 193 B1, /* Removable descender */ 194 B2, /* Strict descender */ 195 NUM_BELOW_STATES 196 } thai_below_start_state[NUM_CONSONANT_TYPES + 1/* For NOT_CONSONANT */] = 197 { 198 B0, /* NC */ 199 B0, /* AC */ 200 B1, /* RC */ 201 B2, /* DC */ 202 B2, /* NOT_CONSONANT */ 203 }; 204 205 static const struct thai_below_state_machine_edge_t { 206 thai_action_t action; 207 thai_below_state_t next_state; 208 } thai_below_state_machine[NUM_BELOW_STATES][NUM_MARK_TYPES] = 209 { /*AV*/ /*BV*/ /*T*/ 210 /*B0*/ {{NOP,B0}, {NOP,B2}, {NOP, B0}}, 211 /*B1*/ {{NOP,B1}, {RD, B2}, {NOP, B1}}, 212 /*B2*/ {{NOP,B2}, {SD, B2}, {NOP, B2}}, 213 }; 214 215 216 static void 217 do_thai_pua_shaping (const hb_ot_shape_plan_t *plan HB_UNUSED, 218 hb_buffer_t *buffer, 219 hb_font_t *font) 220 { 221 thai_above_state_t above_state = thai_above_start_state[NOT_CONSONANT]; 222 thai_below_state_t below_state = thai_below_start_state[NOT_CONSONANT]; 223 unsigned int base = 0; 224 225 hb_glyph_info_t *info = buffer->info; 226 unsigned int count = buffer->len; 227 for (unsigned int i = 0; i < count; i++) 228 { 229 thai_mark_type_t mt = get_mark_type (info[i].codepoint); 230 231 if (mt == NOT_MARK) { 232 thai_consonant_type_t ct = get_consonant_type (info[i].codepoint); 233 above_state = thai_above_start_state[ct]; 234 below_state = thai_below_start_state[ct]; 235 base = i; 236 continue; 237 } 238 239 const thai_above_state_machine_edge_t &above_edge = thai_above_state_machine[above_state][mt]; 240 const thai_below_state_machine_edge_t &below_edge = thai_below_state_machine[below_state][mt]; 241 above_state = above_edge.next_state; 242 below_state = below_edge.next_state; 243 244 /* At least one of the above/below actions is NOP. */ 245 thai_action_t action = above_edge.action != NOP ? above_edge.action : below_edge.action; 246 247 buffer->unsafe_to_break (base, i); 248 if (action == RD) 249 info[base].codepoint = thai_pua_shape (info[base].codepoint, action, font); 250 else 251 info[i].codepoint = thai_pua_shape (info[i].codepoint, action, font); 252 } 253 } 254 255 256 static void 257 preprocess_text_thai (const hb_ot_shape_plan_t *plan, 258 hb_buffer_t *buffer, 259 hb_font_t *font) 260 { 261 /* This function implements the shaping logic documented here: 262 * 263 * http://linux.thai.net/~thep/th-otf/shaping.html 264 * 265 * The first shaping rule listed there is needed even if the font has Thai 266 * OpenType tables. The rest do fallback positioning based on PUA codepoints. 267 * We implement that only if there exist no Thai GSUB in the font. 268 */ 269 270 /* The following is NOT specified in the MS OT Thai spec, however, it seems 271 * to be what Uniscribe and other engines implement. According to Eric Muller: 272 * 273 * When you have a SARA AM, decompose it in NIKHAHIT + SARA AA, *and* move the 274 * NIKHAHIT backwards over any tone mark (0E48-0E4B). 275 * 276 * <0E14, 0E4B, 0E33> -> <0E14, 0E4D, 0E4B, 0E32> 277 * 278 * This reordering is legit only when the NIKHAHIT comes from a SARA AM, not 279 * when it's there to start with. The string <0E14, 0E4B, 0E4D> is probably 280 * not what a user wanted, but the rendering is nevertheless nikhahit above 281 * chattawa. 282 * 283 * Same for Lao. 284 * 285 * Note: 286 * 287 * Uniscribe also does some below-marks reordering. Namely, it positions U+0E3A 288 * after U+0E38 and U+0E39. We do that by modifying the ccc for U+0E3A. 289 * See unicode->modified_combining_class (). Lao does NOT have a U+0E3A 290 * equivalent. 291 */ 292 293 294 /* 295 * Here are the characters of significance: 296 * 297 * Thai Lao 298 * SARA AM: U+0E33 U+0EB3 299 * SARA AA: U+0E32 U+0EB2 300 * Nikhahit: U+0E4D U+0ECD 301 * 302 * Testing shows that Uniscribe reorder the following marks: 303 * Thai: <0E31,0E34..0E37,0E47..0E4E> 304 * Lao: <0EB1,0EB4..0EB7,0EC7..0ECE> 305 * 306 * Note how the Lao versions are the same as Thai + 0x80. 307 */ 308 309 /* We only get one script at a time, so a script-agnostic implementation 310 * is adequate here. */ 311 #define IS_SARA_AM(x) (((x) & ~0x0080u) == 0x0E33u) 312 #define NIKHAHIT_FROM_SARA_AM(x) ((x) - 0x0E33u + 0x0E4Du) 313 #define SARA_AA_FROM_SARA_AM(x) ((x) - 1) 314 #define IS_TONE_MARK(x) (hb_in_ranges<hb_codepoint_t> ((x) & ~0x0080u, 0x0E34u, 0x0E37u, 0x0E47u, 0x0E4Eu, 0x0E31u, 0x0E31u)) 315 316 buffer->clear_output (); 317 unsigned int count = buffer->len; 318 for (buffer->idx = 0; buffer->idx < count && !buffer->in_error;) 319 { 320 hb_codepoint_t u = buffer->cur().codepoint; 321 if (likely (!IS_SARA_AM (u))) { 322 buffer->next_glyph (); 323 continue; 324 } 325 326 /* Is SARA AM. Decompose and reorder. */ 327 hb_codepoint_t decomposed[2] = {hb_codepoint_t (NIKHAHIT_FROM_SARA_AM (u)), 328 hb_codepoint_t (SARA_AA_FROM_SARA_AM (u))}; 329 buffer->replace_glyphs (1, 2, decomposed); 330 if (unlikely (buffer->in_error)) 331 return; 332 333 /* Make Nikhahit be recognized as a ccc=0 mark when zeroing widths. */ 334 unsigned int end = buffer->out_len; 335 _hb_glyph_info_set_general_category (&buffer->out_info[end - 2], HB_UNICODE_GENERAL_CATEGORY_NON_SPACING_MARK); 336 337 /* Ok, let's see... */ 338 unsigned int start = end - 2; 339 while (start > 0 && IS_TONE_MARK (buffer->out_info[start - 1].codepoint)) 340 start--; 341 342 if (start + 2 < end) 343 { 344 /* Move Nikhahit (end-2) to the beginning */ 345 buffer->merge_out_clusters (start, end); 346 hb_glyph_info_t t = buffer->out_info[end - 2]; 347 memmove (buffer->out_info + start + 1, 348 buffer->out_info + start, 349 sizeof (buffer->out_info[0]) * (end - start - 2)); 350 buffer->out_info[start] = t; 351 } 352 else 353 { 354 /* Since we decomposed, and NIKHAHIT is combining, merge clusters with the 355 * previous cluster. */ 356 if (start && buffer->cluster_level == HB_BUFFER_CLUSTER_LEVEL_MONOTONE_GRAPHEMES) 357 buffer->merge_out_clusters (start - 1, end); 358 } 359 } 360 buffer->swap_buffers (); 361 362 /* If font has Thai GSUB, we are done. */ 363 if (plan->props.script == HB_SCRIPT_THAI && !plan->map.found_script[0]) 364 do_thai_pua_shaping (plan, buffer, font); 365 } 366 367 const hb_ot_complex_shaper_t _hb_ot_complex_shaper_thai = 368 { 369 nullptr, /* collect_features */ 370 nullptr, /* override_features */ 371 nullptr, /* data_create */ 372 nullptr, /* data_destroy */ 373 preprocess_text_thai, 374 nullptr, /* postprocess_glyphs */ 375 HB_OT_SHAPE_NORMALIZATION_MODE_DEFAULT, 376 nullptr, /* decompose */ 377 nullptr, /* compose */ 378 nullptr, /* setup_masks */ 379 nullptr, /* disable_otl */ 380 nullptr, /* reorder_marks */ 381 HB_OT_SHAPE_ZERO_WIDTH_MARKS_BY_GDEF_LATE, 382 false,/* fallback_position */ 383 }; 384
