/src/skia/third_party/externals/harfbuzz/src/hb-ot-shape-complex-thai.cc
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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.hh" |
28 | | |
29 | | #ifndef HB_NO_OT_SHAPE |
30 | | |
31 | | #include "hb-ot-shape-complex.hh" |
32 | | |
33 | | |
34 | | /* Thai / Lao shaper */ |
35 | | |
36 | | |
37 | | /* PUA shaping */ |
38 | | |
39 | | |
40 | | enum thai_consonant_type_t |
41 | | { |
42 | | NC, |
43 | | AC, |
44 | | RC, |
45 | | DC, |
46 | | NOT_CONSONANT, |
47 | | NUM_CONSONANT_TYPES = NOT_CONSONANT |
48 | | }; |
49 | | |
50 | | static thai_consonant_type_t |
51 | | get_consonant_type (hb_codepoint_t u) |
52 | 366k | { |
53 | 366k | if (u == 0x0E1Bu || u == 0x0E1Du || u == 0x0E1Fu/* || u == 0x0E2Cu*/) |
54 | 341 | return AC; |
55 | 366k | if (u == 0x0E0Du || u == 0x0E10u) |
56 | 114 | return RC; |
57 | 366k | if (u == 0x0E0Eu || u == 0x0E0Fu) |
58 | 36 | return DC; |
59 | 366k | if (hb_in_range<hb_codepoint_t> (u, 0x0E01u, 0x0E2Eu)) |
60 | 841 | return NC; |
61 | 365k | return NOT_CONSONANT; |
62 | 365k | } |
63 | | |
64 | | |
65 | | enum thai_mark_type_t |
66 | | { |
67 | | AV, |
68 | | BV, |
69 | | T, |
70 | | NOT_MARK, |
71 | | NUM_MARK_TYPES = NOT_MARK |
72 | | }; |
73 | | |
74 | | static thai_mark_type_t |
75 | | get_mark_type (hb_codepoint_t u) |
76 | 549k | { |
77 | 549k | if (u == 0x0E31u || hb_in_range<hb_codepoint_t> (u, 0x0E34u, 0x0E37u) || |
78 | 465k | u == 0x0E47u || hb_in_range<hb_codepoint_t> (u, 0x0E4Du, 0x0E4Eu)) |
79 | 182k | return AV; |
80 | 367k | if (hb_in_range<hb_codepoint_t> (u, 0x0E38u, 0x0E3Au)) |
81 | 205 | return BV; |
82 | 366k | if (hb_in_range<hb_codepoint_t> (u, 0x0E48u, 0x0E4Cu)) |
83 | 21 | return T; |
84 | 366k | return NOT_MARK; |
85 | 366k | } |
86 | | |
87 | | |
88 | | enum thai_action_t |
89 | | { |
90 | | NOP, |
91 | | SD, /* Shift combining-mark down */ |
92 | | SL, /* Shift combining-mark left */ |
93 | | SDL, /* Shift combining-mark down-left */ |
94 | | RD /* Remove descender from base */ |
95 | | }; |
96 | | |
97 | | static hb_codepoint_t |
98 | | thai_pua_shape (hb_codepoint_t u, thai_action_t action, hb_font_t *font) |
99 | 182k | { |
100 | 182k | struct thai_pua_mapping_t { |
101 | 182k | hb_codepoint_t u; |
102 | 182k | hb_codepoint_t win_pua; |
103 | 182k | hb_codepoint_t mac_pua; |
104 | 182k | } const *pua_mappings = nullptr; |
105 | 182k | static const thai_pua_mapping_t SD_mappings[] = { |
106 | 182k | {0x0E48u, 0xF70Au, 0xF88Bu}, /* MAI EK */ |
107 | 182k | {0x0E49u, 0xF70Bu, 0xF88Eu}, /* MAI THO */ |
108 | 182k | {0x0E4Au, 0xF70Cu, 0xF891u}, /* MAI TRI */ |
109 | 182k | {0x0E4Bu, 0xF70Du, 0xF894u}, /* MAI CHATTAWA */ |
110 | 182k | {0x0E4Cu, 0xF70Eu, 0xF897u}, /* THANTHAKHAT */ |
111 | 182k | {0x0E38u, 0xF718u, 0xF89Bu}, /* SARA U */ |
112 | 182k | {0x0E39u, 0xF719u, 0xF89Cu}, /* SARA UU */ |
113 | 182k | {0x0E3Au, 0xF71Au, 0xF89Du}, /* PHINTHU */ |
114 | 182k | {0x0000u, 0x0000u, 0x0000u} |
115 | 182k | }; |
116 | 182k | static const thai_pua_mapping_t SDL_mappings[] = { |
117 | 182k | {0x0E48u, 0xF705u, 0xF88Cu}, /* MAI EK */ |
118 | 182k | {0x0E49u, 0xF706u, 0xF88Fu}, /* MAI THO */ |
119 | 182k | {0x0E4Au, 0xF707u, 0xF892u}, /* MAI TRI */ |
120 | 182k | {0x0E4Bu, 0xF708u, 0xF895u}, /* MAI CHATTAWA */ |
121 | 182k | {0x0E4Cu, 0xF709u, 0xF898u}, /* THANTHAKHAT */ |
122 | 182k | {0x0000u, 0x0000u, 0x0000u} |
123 | 182k | }; |
124 | 182k | static const thai_pua_mapping_t SL_mappings[] = { |
125 | 182k | {0x0E48u, 0xF713u, 0xF88Au}, /* MAI EK */ |
126 | 182k | {0x0E49u, 0xF714u, 0xF88Du}, /* MAI THO */ |
127 | 182k | {0x0E4Au, 0xF715u, 0xF890u}, /* MAI TRI */ |
128 | 182k | {0x0E4Bu, 0xF716u, 0xF893u}, /* MAI CHATTAWA */ |
129 | 182k | {0x0E4Cu, 0xF717u, 0xF896u}, /* THANTHAKHAT */ |
130 | 182k | {0x0E31u, 0xF710u, 0xF884u}, /* MAI HAN-AKAT */ |
131 | 182k | {0x0E34u, 0xF701u, 0xF885u}, /* SARA I */ |
132 | 182k | {0x0E35u, 0xF702u, 0xF886u}, /* SARA II */ |
133 | 182k | {0x0E36u, 0xF703u, 0xF887u}, /* SARA UE */ |
134 | 182k | {0x0E37u, 0xF704u, 0xF888u}, /* SARA UEE */ |
135 | 182k | {0x0E47u, 0xF712u, 0xF889u}, /* MAITAIKHU */ |
136 | 182k | {0x0E4Du, 0xF711u, 0xF899u}, /* NIKHAHIT */ |
137 | 182k | {0x0000u, 0x0000u, 0x0000u} |
138 | 182k | }; |
139 | 182k | static const thai_pua_mapping_t RD_mappings[] = { |
140 | 182k | {0x0E0Du, 0xF70Fu, 0xF89Au}, /* YO YING */ |
141 | 182k | {0x0E10u, 0xF700u, 0xF89Eu}, /* THO THAN */ |
142 | 182k | {0x0000u, 0x0000u, 0x0000u} |
143 | 182k | }; |
144 | | |
145 | 182k | switch (action) { |
146 | 182k | case NOP: return u; |
147 | 205 | case SD: pua_mappings = SD_mappings; break; |
148 | 0 | case SDL: pua_mappings = SDL_mappings; break; |
149 | 0 | case SL: pua_mappings = SL_mappings; break; |
150 | 0 | case RD: pua_mappings = RD_mappings; break; |
151 | 205 | } |
152 | 1.25k | for (; pua_mappings->u; pua_mappings++) |
153 | 1.25k | if (pua_mappings->u == u) |
154 | 205 | { |
155 | 205 | hb_codepoint_t glyph; |
156 | 205 | if (hb_font_get_glyph (font, pua_mappings->win_pua, 0, &glyph)) |
157 | 0 | return pua_mappings->win_pua; |
158 | 205 | if (hb_font_get_glyph (font, pua_mappings->mac_pua, 0, &glyph)) |
159 | 0 | return pua_mappings->mac_pua; |
160 | 205 | break; |
161 | 205 | } |
162 | 205 | return u; |
163 | 205 | } |
164 | | |
165 | | |
166 | | static enum thai_above_state_t |
167 | | { /* Cluster above looks like: */ |
168 | | T0, /* ⣤ */ |
169 | | T1, /* ⣼ */ |
170 | | T2, /* ⣾ */ |
171 | | T3, /* ⣿ */ |
172 | | NUM_ABOVE_STATES |
173 | | } thai_above_start_state[NUM_CONSONANT_TYPES + 1/* For NOT_CONSONANT */] = |
174 | | { |
175 | | T0, /* NC */ |
176 | | T1, /* AC */ |
177 | | T0, /* RC */ |
178 | | T0, /* DC */ |
179 | | T3, /* NOT_CONSONANT */ |
180 | | }; |
181 | | |
182 | | static const struct thai_above_state_machine_edge_t { |
183 | | thai_action_t action; |
184 | | thai_above_state_t next_state; |
185 | | } thai_above_state_machine[NUM_ABOVE_STATES][NUM_MARK_TYPES] = |
186 | | { /*AV*/ /*BV*/ /*T*/ |
187 | | /*T0*/ {{NOP,T3}, {NOP,T0}, {SD, T3}}, |
188 | | /*T1*/ {{SL, T2}, {NOP,T1}, {SDL,T2}}, |
189 | | /*T2*/ {{NOP,T3}, {NOP,T2}, {SL, T3}}, |
190 | | /*T3*/ {{NOP,T3}, {NOP,T3}, {NOP,T3}}, |
191 | | }; |
192 | | |
193 | | |
194 | | static enum thai_below_state_t |
195 | | { |
196 | | B0, /* No descender */ |
197 | | B1, /* Removable descender */ |
198 | | B2, /* Strict descender */ |
199 | | NUM_BELOW_STATES |
200 | | } thai_below_start_state[NUM_CONSONANT_TYPES + 1/* For NOT_CONSONANT */] = |
201 | | { |
202 | | B0, /* NC */ |
203 | | B0, /* AC */ |
204 | | B1, /* RC */ |
205 | | B2, /* DC */ |
206 | | B2, /* NOT_CONSONANT */ |
207 | | }; |
208 | | |
209 | | static const struct thai_below_state_machine_edge_t { |
210 | | thai_action_t action; |
211 | | thai_below_state_t next_state; |
212 | | } thai_below_state_machine[NUM_BELOW_STATES][NUM_MARK_TYPES] = |
213 | | { /*AV*/ /*BV*/ /*T*/ |
214 | | /*B0*/ {{NOP,B0}, {NOP,B2}, {NOP, B0}}, |
215 | | /*B1*/ {{NOP,B1}, {RD, B2}, {NOP, B1}}, |
216 | | /*B2*/ {{NOP,B2}, {SD, B2}, {NOP, B2}}, |
217 | | }; |
218 | | |
219 | | |
220 | | static void |
221 | | do_thai_pua_shaping (const hb_ot_shape_plan_t *plan HB_UNUSED, |
222 | | hb_buffer_t *buffer, |
223 | | hb_font_t *font) |
224 | 19.8k | { |
225 | | #ifdef HB_NO_OT_SHAPE_COMPLEX_THAI_FALLBACK |
226 | | return; |
227 | | #endif |
228 | | |
229 | 19.8k | thai_above_state_t above_state = thai_above_start_state[NOT_CONSONANT]; |
230 | 19.8k | thai_below_state_t below_state = thai_below_start_state[NOT_CONSONANT]; |
231 | 19.8k | unsigned int base = 0; |
232 | | |
233 | 19.8k | hb_glyph_info_t *info = buffer->info; |
234 | 19.8k | unsigned int count = buffer->len; |
235 | 569k | for (unsigned int i = 0; i < count; i++) |
236 | 549k | { |
237 | 549k | thai_mark_type_t mt = get_mark_type (info[i].codepoint); |
238 | | |
239 | 549k | if (mt == NOT_MARK) { |
240 | 366k | thai_consonant_type_t ct = get_consonant_type (info[i].codepoint); |
241 | 366k | above_state = thai_above_start_state[ct]; |
242 | 366k | below_state = thai_below_start_state[ct]; |
243 | 366k | base = i; |
244 | 366k | continue; |
245 | 366k | } |
246 | | |
247 | 182k | const thai_above_state_machine_edge_t &above_edge = thai_above_state_machine[above_state][mt]; |
248 | 182k | const thai_below_state_machine_edge_t &below_edge = thai_below_state_machine[below_state][mt]; |
249 | 182k | above_state = above_edge.next_state; |
250 | 182k | below_state = below_edge.next_state; |
251 | | |
252 | | /* At least one of the above/below actions is NOP. */ |
253 | 182k | thai_action_t action = above_edge.action != NOP ? above_edge.action : below_edge.action; |
254 | | |
255 | 182k | buffer->unsafe_to_break (base, i); |
256 | 182k | if (action == RD) |
257 | 0 | info[base].codepoint = thai_pua_shape (info[base].codepoint, action, font); |
258 | 182k | else |
259 | 182k | info[i].codepoint = thai_pua_shape (info[i].codepoint, action, font); |
260 | 182k | } |
261 | 19.8k | } |
262 | | |
263 | | |
264 | | static void |
265 | | preprocess_text_thai (const hb_ot_shape_plan_t *plan, |
266 | | hb_buffer_t *buffer, |
267 | | hb_font_t *font) |
268 | 23.4k | { |
269 | | /* This function implements the shaping logic documented here: |
270 | | * |
271 | | * https://linux.thai.net/~thep/th-otf/shaping.html |
272 | | * |
273 | | * The first shaping rule listed there is needed even if the font has Thai |
274 | | * OpenType tables. The rest do fallback positioning based on PUA codepoints. |
275 | | * We implement that only if there exist no Thai GSUB in the font. |
276 | | */ |
277 | | |
278 | | /* The following is NOT specified in the MS OT Thai spec, however, it seems |
279 | | * to be what Uniscribe and other engines implement. According to Eric Muller: |
280 | | * |
281 | | * When you have a SARA AM, decompose it in NIKHAHIT + SARA AA, *and* move the |
282 | | * NIKHAHIT backwards over any tone mark (0E48-0E4B). |
283 | | * |
284 | | * <0E14, 0E4B, 0E33> -> <0E14, 0E4D, 0E4B, 0E32> |
285 | | * |
286 | | * This reordering is legit only when the NIKHAHIT comes from a SARA AM, not |
287 | | * when it's there to start with. The string <0E14, 0E4B, 0E4D> is probably |
288 | | * not what a user wanted, but the rendering is nevertheless nikhahit above |
289 | | * chattawa. |
290 | | * |
291 | | * Same for Lao. |
292 | | * |
293 | | * Note: |
294 | | * |
295 | | * Uniscribe also does some below-marks reordering. Namely, it positions U+0E3A |
296 | | * after U+0E38 and U+0E39. We do that by modifying the ccc for U+0E3A. |
297 | | * See unicode->modified_combining_class (). Lao does NOT have a U+0E3A |
298 | | * equivalent. |
299 | | */ |
300 | | |
301 | | |
302 | | /* |
303 | | * Here are the characters of significance: |
304 | | * |
305 | | * Thai Lao |
306 | | * SARA AM: U+0E33 U+0EB3 |
307 | | * SARA AA: U+0E32 U+0EB2 |
308 | | * Nikhahit: U+0E4D U+0ECD |
309 | | * |
310 | | * Testing shows that Uniscribe reorder the following marks: |
311 | | * Thai: <0E31,0E34..0E37,0E47..0E4E> |
312 | | * Lao: <0EB1,0EB4..0EB7,0EC7..0ECE> |
313 | | * |
314 | | * Note how the Lao versions are the same as Thai + 0x80. |
315 | | */ |
316 | | |
317 | | /* We only get one script at a time, so a script-agnostic implementation |
318 | | * is adequate here. */ |
319 | 23.4k | #define IS_SARA_AM(x) (((x) & ~0x0080u) == 0x0E33u) |
320 | 101k | #define NIKHAHIT_FROM_SARA_AM(x) ((x) - 0x0E33u + 0x0E4Du) |
321 | 23.4k | #define SARA_AA_FROM_SARA_AM(x) ((x) - 1) |
322 | 161k | #define IS_TONE_MARK(x) (hb_in_ranges<hb_codepoint_t> ((x) & ~0x0080u, 0x0E34u, 0x0E37u, 0x0E47u, 0x0E4Eu, 0x0E31u, 0x0E31u)) |
323 | | |
324 | 23.4k | buffer->clear_output (); |
325 | 23.4k | unsigned int count = buffer->len; |
326 | 527k | for (buffer->idx = 0; buffer->idx < count /* No need for: && buffer->successful */;) |
327 | 504k | { |
328 | 504k | hb_codepoint_t u = buffer->cur().codepoint; |
329 | 504k | if (likely (!IS_SARA_AM (u))) |
330 | 402k | { |
331 | 402k | if (unlikely (!buffer->next_glyph ())) break; |
332 | 402k | continue; |
333 | 402k | } |
334 | | |
335 | | /* Is SARA AM. Decompose and reorder. */ |
336 | 101k | (void) buffer->output_glyph (NIKHAHIT_FROM_SARA_AM (u)); |
337 | 101k | _hb_glyph_info_set_continuation (&buffer->prev()); |
338 | 101k | if (unlikely (!buffer->replace_glyph (SARA_AA_FROM_SARA_AM (u)))) break; |
339 | | |
340 | | /* Make Nikhahit be recognized as a ccc=0 mark when zeroing widths. */ |
341 | 101k | unsigned int end = buffer->out_len; |
342 | 101k | _hb_glyph_info_set_general_category (&buffer->out_info[end - 2], HB_UNICODE_GENERAL_CATEGORY_NON_SPACING_MARK); |
343 | | |
344 | | /* Ok, let's see... */ |
345 | 101k | unsigned int start = end - 2; |
346 | 178k | while (start > 0 && IS_TONE_MARK (buffer->out_info[start - 1].codepoint)) |
347 | 76.7k | start--; |
348 | | |
349 | 101k | if (start + 2 < end) |
350 | 76.7k | { |
351 | | /* Move Nikhahit (end-2) to the beginning */ |
352 | 76.7k | buffer->merge_out_clusters (start, end); |
353 | 76.7k | hb_glyph_info_t t = buffer->out_info[end - 2]; |
354 | 76.7k | memmove (buffer->out_info + start + 1, |
355 | 76.7k | buffer->out_info + start, |
356 | 76.7k | sizeof (buffer->out_info[0]) * (end - start - 2)); |
357 | 76.7k | buffer->out_info[start] = t; |
358 | 76.7k | } |
359 | 24.8k | else |
360 | 24.8k | { |
361 | | /* Since we decomposed, and NIKHAHIT is combining, merge clusters with the |
362 | | * previous cluster. */ |
363 | 24.8k | if (start && buffer->cluster_level == HB_BUFFER_CLUSTER_LEVEL_MONOTONE_GRAPHEMES) |
364 | 0 | buffer->merge_out_clusters (start - 1, end); |
365 | 24.8k | } |
366 | 101k | } |
367 | 23.4k | buffer->swap_buffers (); |
368 | | |
369 | | /* If font has Thai GSUB, we are done. */ |
370 | 23.4k | if (plan->props.script == HB_SCRIPT_THAI && !plan->map.found_script[0]) |
371 | 19.8k | do_thai_pua_shaping (plan, buffer, font); |
372 | 23.4k | } |
373 | | |
374 | | const hb_ot_complex_shaper_t _hb_ot_complex_shaper_thai = |
375 | | { |
376 | | nullptr, /* collect_features */ |
377 | | nullptr, /* override_features */ |
378 | | nullptr, /* data_create */ |
379 | | nullptr, /* data_destroy */ |
380 | | preprocess_text_thai, |
381 | | nullptr, /* postprocess_glyphs */ |
382 | | HB_OT_SHAPE_NORMALIZATION_MODE_DEFAULT, |
383 | | nullptr, /* decompose */ |
384 | | nullptr, /* compose */ |
385 | | nullptr, /* setup_masks */ |
386 | | HB_TAG_NONE, /* gpos_tag */ |
387 | | nullptr, /* reorder_marks */ |
388 | | HB_OT_SHAPE_ZERO_WIDTH_MARKS_BY_GDEF_LATE, |
389 | | false,/* fallback_position */ |
390 | | }; |
391 | | |
392 | | |
393 | | #endif |