2 * Copyright © 2011 Google, Inc.
4 * This is part of HarfBuzz, a text shaping library.
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.
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
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.
24 * Google Author(s): Behdad Esfahbod
27 #include "hb-ot-shape-complex-private.hh"
32 /* buffer var allocations */
33 #define indic_category() complex_var_persistent_u8_0() /* indic_category_t */
34 #define indic_position() complex_var_persistent_u8_1() /* indic_matra_category_t */
36 #define INDIC_TABLE_ELEMENT_TYPE uint8_t
38 /* Cateories used in the OpenType spec:
39 * https://www.microsoft.com/typography/otfntdev/devanot/shaping.aspx
41 /* Note: This enum is duplicated in the -machine.rl source file.
42 * Not sure how to avoid duplication. */
43 enum indic_category_t {
46 OT_Ra, /* Not explicitly listed in the OT spec, but used in the grammar. */
59 /* Visual positions in a syllable from left to right. */
60 enum indic_position_t {
67 POS_INHERIT /* For Halant, Nukta, ZWJ, ZWNJ */
70 /* Categories used in IndicSyllabicCategory.txt from UCD */
71 /* The assignments are guesswork */
72 enum indic_syllabic_category_t {
73 INDIC_SYLLABIC_CATEGORY_OTHER = OT_X,
75 INDIC_SYLLABIC_CATEGORY_AVAGRAHA = OT_X,
76 INDIC_SYLLABIC_CATEGORY_BINDU = OT_SM,
77 INDIC_SYLLABIC_CATEGORY_CONSONANT = OT_C,
78 INDIC_SYLLABIC_CATEGORY_CONSONANT_DEAD = OT_C,
79 INDIC_SYLLABIC_CATEGORY_CONSONANT_FINAL = OT_C,
80 INDIC_SYLLABIC_CATEGORY_CONSONANT_HEAD_LETTER = OT_C,
81 INDIC_SYLLABIC_CATEGORY_CONSONANT_MEDIAL = OT_C,
82 INDIC_SYLLABIC_CATEGORY_CONSONANT_PLACEHOLDER = OT_NBSP,
83 INDIC_SYLLABIC_CATEGORY_CONSONANT_SUBJOINED = OT_C,
84 INDIC_SYLLABIC_CATEGORY_CONSONANT_REPHA = OT_C,
85 INDIC_SYLLABIC_CATEGORY_MODIFYING_LETTER = OT_X,
86 INDIC_SYLLABIC_CATEGORY_NUKTA = OT_N,
87 INDIC_SYLLABIC_CATEGORY_REGISTER_SHIFTER = OT_X,
88 INDIC_SYLLABIC_CATEGORY_TONE_LETTER = OT_X,
89 INDIC_SYLLABIC_CATEGORY_TONE_MARK = OT_X,
90 INDIC_SYLLABIC_CATEGORY_VIRAMA = OT_H,
91 INDIC_SYLLABIC_CATEGORY_VISARGA = OT_SM,
92 INDIC_SYLLABIC_CATEGORY_VOWEL = OT_V,
93 INDIC_SYLLABIC_CATEGORY_VOWEL_DEPENDENT = OT_M,
94 INDIC_SYLLABIC_CATEGORY_VOWEL_INDEPENDENT = OT_V
97 /* Categories used in IndicSMatraCategory.txt from UCD */
98 enum indic_matra_category_t {
99 INDIC_MATRA_CATEGORY_NOT_APPLICABLE = POS_BASE,
101 INDIC_MATRA_CATEGORY_LEFT = POS_PRE,
102 INDIC_MATRA_CATEGORY_TOP = POS_ABOVE,
103 INDIC_MATRA_CATEGORY_BOTTOM = POS_BELOW,
104 INDIC_MATRA_CATEGORY_RIGHT = POS_POST,
106 /* We don't really care much about these since we decompose them
107 * in the generic pre-shaping layer. They will only be used if
108 * the font does not cover the decomposition. In which case, we
109 * define these as aliases to the place we want the split-matra
110 * glyph to show up. Quite arbitrary. */
111 INDIC_MATRA_CATEGORY_BOTTOM_AND_RIGHT = INDIC_MATRA_CATEGORY_BOTTOM,
112 INDIC_MATRA_CATEGORY_LEFT_AND_RIGHT = INDIC_MATRA_CATEGORY_LEFT,
113 INDIC_MATRA_CATEGORY_TOP_AND_BOTTOM = INDIC_MATRA_CATEGORY_BOTTOM,
114 INDIC_MATRA_CATEGORY_TOP_AND_BOTTOM_AND_RIGHT = INDIC_MATRA_CATEGORY_BOTTOM,
115 INDIC_MATRA_CATEGORY_TOP_AND_LEFT = INDIC_MATRA_CATEGORY_LEFT,
116 INDIC_MATRA_CATEGORY_TOP_AND_LEFT_AND_RIGHT = INDIC_MATRA_CATEGORY_LEFT,
117 INDIC_MATRA_CATEGORY_TOP_AND_RIGHT = INDIC_MATRA_CATEGORY_RIGHT,
119 INDIC_MATRA_CATEGORY_INVISIBLE = INDIC_MATRA_CATEGORY_NOT_APPLICABLE,
120 INDIC_MATRA_CATEGORY_OVERSTRUCK = INDIC_MATRA_CATEGORY_NOT_APPLICABLE,
121 INDIC_MATRA_CATEGORY_VISUAL_ORDER_LEFT = INDIC_MATRA_CATEGORY_NOT_APPLICABLE
124 /* Note: We use ASSERT_STATIC_EXPR_ZERO() instead of ASSERT_STATIC_EXPR() and the comma operation
125 * because gcc fails to optimize the latter and fills the table in at runtime. */
126 #define INDIC_COMBINE_CATEGORIES(S,M) \
127 (ASSERT_STATIC_EXPR_ZERO (M == INDIC_MATRA_CATEGORY_NOT_APPLICABLE || (S == INDIC_SYLLABIC_CATEGORY_VIRAMA || S == INDIC_SYLLABIC_CATEGORY_VOWEL_DEPENDENT)) + \
128 ASSERT_STATIC_EXPR_ZERO (S < 16 && M < 16) + \
131 #include "hb-ot-shape-complex-indic-table.hh"
134 * This is a hack for now. We should:
135 * 1. Move this data into the main Indic table,
137 * 2. Probe font lookups to determine consonant positions.
139 static const struct consonant_position_t {
141 indic_position_t position;
142 } consonant_positions[] = {
240 compare_codepoint (const void *pa, const void *pb)
242 hb_codepoint_t a = * (hb_codepoint_t *) pa;
243 hb_codepoint_t b = * (hb_codepoint_t *) pb;
245 return a < b ? -1 : a == b ? 0 : +1;
248 static indic_position_t
249 consonant_position (hb_codepoint_t u)
251 consonant_position_t *record;
253 record = (consonant_position_t *) bsearch (&u, consonant_positions,
254 ARRAY_LENGTH (consonant_positions),
255 sizeof (consonant_positions[0]),
258 return record ? record->position : POS_BASE;
262 static const struct {
265 } indic_basic_features[] =
267 {HB_TAG('n','u','k','t'), true},
268 {HB_TAG('a','k','h','n'), false},
269 {HB_TAG('r','p','h','f'), false},
270 {HB_TAG('r','k','r','f'), false},
271 {HB_TAG('p','r','e','f'), false},
272 {HB_TAG('b','l','w','f'), false},
273 {HB_TAG('h','a','l','f'), false},
274 {HB_TAG('v','a','t','u'), true},
275 {HB_TAG('p','s','t','f'), false},
276 {HB_TAG('c','j','c','t'), true},
279 /* Same order as the indic_basic_features array */
293 static const hb_tag_t indic_other_features[] =
295 HB_TAG('p','r','e','s'),
296 HB_TAG('a','b','v','s'),
297 HB_TAG('b','l','w','s'),
298 HB_TAG('p','s','t','s'),
299 HB_TAG('h','a','l','n'),
301 HB_TAG('d','i','s','t'),
302 HB_TAG('a','b','v','m'),
303 HB_TAG('b','l','w','m'),
308 initial_reordering (const hb_ot_map_t *map,
311 void *user_data HB_UNUSED);
313 final_reordering (const hb_ot_map_t *map,
316 void *user_data HB_UNUSED);
319 _hb_ot_shape_complex_collect_features_indic (hb_ot_map_builder_t *map, const hb_segment_properties_t *props)
321 map->add_bool_feature (HB_TAG('l','o','c','l'));
322 /* The Indic specs do not require ccmp, but we apply it here since if
323 * there is a use of it, it's typically at the beginning. */
324 map->add_bool_feature (HB_TAG('c','c','m','p'));
326 map->add_gsub_pause (initial_reordering, NULL);
328 for (unsigned int i = 0; i < ARRAY_LENGTH (indic_basic_features); i++)
329 map->add_bool_feature (indic_basic_features[i].tag, indic_basic_features[i].is_global);
331 map->add_gsub_pause (final_reordering, NULL);
333 for (unsigned int i = 0; i < ARRAY_LENGTH (indic_other_features); i++)
334 map->add_bool_feature (indic_other_features[i], true);
339 _hb_ot_shape_complex_prefer_decomposed_indic (void)
341 /* We want split matras decomposed by the common shaping logic. */
347 _hb_ot_shape_complex_setup_masks_indic (hb_ot_map_t *map, hb_buffer_t *buffer)
349 HB_BUFFER_ALLOCATE_VAR (buffer, indic_category);
350 HB_BUFFER_ALLOCATE_VAR (buffer, indic_position);
352 /* We cannot setup masks here. We save information about characters
353 * and setup masks later on in a pause-callback. */
355 unsigned int count = buffer->len;
356 for (unsigned int i = 0; i < count; i++)
358 unsigned int type = get_indic_categories (buffer->info[i].codepoint);
360 buffer->info[i].indic_category() = type & 0x0F;
361 buffer->info[i].indic_position() = type >> 4;
363 if (buffer->info[i].indic_category() == OT_C)
364 buffer->info[i].indic_position() = consonant_position (buffer->info[i].codepoint);
370 found_consonant_syllable (const hb_ot_map_t *map, hb_buffer_t *buffer, hb_mask_t *mask_array,
371 unsigned int start, unsigned int end)
376 * https://www.microsoft.com/typography/otfntdev/devanot/shaping.aspx */
378 /* 1. Find base consonant:
380 * The shaping engine finds the base consonant of the syllable, using the
381 * following algorithm: starting from the end of the syllable, move backwards
382 * until a consonant is found that does not have a below-base or post-base
383 * form (post-base forms have to follow below-base forms), or that is not a
384 * pre-base reordering Ra, or arrive at the first consonant. The consonant
385 * stopped at will be the base.
387 * o If the syllable starts with Ra + Halant (in a script that has Reph)
388 * and has more than one consonant, Ra is excluded from candidates for
392 unsigned int base = 0;
394 /* -> starting from the end of the syllable, move backwards */
398 /* -> until a consonant is found */
399 if (buffer->info[i].indic_category() == OT_C)
401 /* -> that does not have a below-base or post-base form
402 * (post-base forms have to follow below-base forms), */
403 if (buffer->info[i].indic_position() != POS_BELOW &&
404 buffer->info[i].indic_position() != POS_POST)
410 /* TODO: or that is not a pre-base reordering Ra, */
412 /* -> or arrive at the first consonant. The consonant stopped at will be the base. */
417 base = start; /* Just in case... */
420 * If the syllable starts with Ra + Halant (in a script that has Reph)
421 * and has more than one consonant, Ra is excluded from candidates for
422 * base consonants. */
425 /* 2. Decompose and reorder Matras:
427 * Each matra and any syllable modifier sign in the cluster are moved to the
428 * appropriate position relative to the consonant(s) in the cluster. The
429 * shaping engine decomposes two- or three-part matras into their constituent
430 * parts before any repositioning. Matra characters are classified by which
431 * consonant in a conjunct they have affinity for and are reordered to the
432 * following positions:
434 * o Before first half form in the syllable
435 * o After subjoined consonants
436 * o After post-form consonant
437 * o After main consonant (for above marks)
439 * IMPLEMENTATION NOTES:
441 * The normalize() routine has already decomposed matras for us, so we don't
442 * need to worry about that.
446 /* 3. Reorder marks to canonical order:
448 * Adjacent nukta and halant or nukta and vedic sign are always repositioned
449 * if necessary, so that the nukta is first.
451 * IMPLEMENTATION NOTES:
453 * We don't need to do this: the normalize() routine already did this for us.
457 /* Setup masks now */
460 for (i = start; i < base; i++)
461 buffer->info[i].mask |= mask_array[HALF] | mask_array[AKHN];
463 buffer->info[base].mask |= mask_array[AKHN];
465 for (i = base + 1; i < end; i++)
466 buffer->info[i].mask |= mask_array[BLWF] | mask_array[PSTF];
471 found_vowel_syllable (const hb_ot_map_t *map, hb_buffer_t *buffer, hb_mask_t *mask_array,
472 unsigned int start, unsigned int end)
475 * Not clear to me how this should work. Do the matras move to before the
476 * independent vowel? No idea.
481 found_standalone_cluster (const hb_ot_map_t *map, hb_buffer_t *buffer, hb_mask_t *mask_array,
482 unsigned int start, unsigned int end)
485 * Easiest thing to do here is to convert the NBSP to consonant and
486 * call found_consonant_syllable.
491 found_non_indic (const hb_ot_map_t *map, hb_buffer_t *buffer, hb_mask_t *mask_array,
492 unsigned int start, unsigned int end)
494 /* Nothing to do right now. If we ever switch to using the output
495 * buffer in the reordering process, we'd need to next_glyph() here. */
498 #include "hb-ot-shape-complex-indic-machine.hh"
501 initial_reordering (const hb_ot_map_t *map,
504 void *user_data HB_UNUSED)
506 hb_mask_t mask_array[ARRAY_LENGTH (indic_basic_features)] = {0};
507 unsigned int num_masks = ARRAY_LENGTH (indic_basic_features);
508 for (unsigned int i = 0; i < num_masks; i++)
509 mask_array[i] = map->get_1_mask (indic_basic_features[i].tag);
511 find_syllables (map, buffer, mask_array);
515 final_reordering (const hb_ot_map_t *map,
518 void *user_data HB_UNUSED)
520 HB_BUFFER_DEALLOCATE_VAR (buffer, indic_category);
521 HB_BUFFER_DEALLOCATE_VAR (buffer, indic_position);