/* * Copyright © 2011 Google, Inc. * * This is part of HarfBuzz, a text shaping library. * * Permission is hereby granted, without written agreement and without * license or royalty fees, to use, copy, modify, and distribute this * software and its documentation for any purpose, provided that the * above copyright notice and the following two paragraphs appear in * all copies of this software. * * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH * DAMAGE. * * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND * FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS. * * Google Author(s): Behdad Esfahbod */ #include "hb-ot-shape-complex-indic-private.hh" static int compare_codepoint (const void *pa, const void *pb) { hb_codepoint_t a = * (hb_codepoint_t *) pa; hb_codepoint_t b = * (hb_codepoint_t *) pb; return a < b ? -1 : a == b ? 0 : +1; } static indic_position_t consonant_position (hb_codepoint_t u) { consonant_position_t *record; record = (consonant_position_t *) bsearch (&u, consonant_positions, ARRAY_LENGTH (consonant_positions), sizeof (consonant_positions[0]), compare_codepoint); return record ? record->position : POS_BASE; } static bool is_ra (hb_codepoint_t u) { return !!bsearch (&u, ra_chars, ARRAY_LENGTH (ra_chars), sizeof (ra_chars[0]), compare_codepoint); } static bool is_joiner (const hb_glyph_info_t &info) { return !!(FLAG (info.indic_category()) & (FLAG (OT_ZWJ) | FLAG (OT_ZWNJ))); } static bool is_consonant (const hb_glyph_info_t &info) { return !!(FLAG (info.indic_category()) & (FLAG (OT_C) | FLAG (OT_Ra))); } static const struct { hb_tag_t tag; hb_bool_t is_global; } indic_basic_features[] = { {HB_TAG('n','u','k','t'), true}, {HB_TAG('a','k','h','n'), false}, {HB_TAG('r','p','h','f'), false}, {HB_TAG('r','k','r','f'), true}, {HB_TAG('p','r','e','f'), false}, {HB_TAG('b','l','w','f'), false}, {HB_TAG('h','a','l','f'), false}, {HB_TAG('v','a','t','u'), true}, {HB_TAG('p','s','t','f'), false}, {HB_TAG('c','j','c','t'), false}, }; /* Same order as the indic_basic_features array */ enum { _NUKT, AKHN, RPHF, RKRF, PREF, BLWF, HALF, _VATU, PSTF, CJCT }; static const hb_tag_t indic_other_features[] = { HB_TAG('p','r','e','s'), HB_TAG('a','b','v','s'), HB_TAG('b','l','w','s'), HB_TAG('p','s','t','s'), HB_TAG('h','a','l','n'), HB_TAG('d','i','s','t'), HB_TAG('a','b','v','m'), HB_TAG('b','l','w','m'), }; static void initial_reordering (const hb_ot_map_t *map, hb_face_t *face, hb_buffer_t *buffer, void *user_data HB_UNUSED); static void final_reordering (const hb_ot_map_t *map, hb_face_t *face, hb_buffer_t *buffer, void *user_data HB_UNUSED); void _hb_ot_shape_complex_collect_features_indic (hb_ot_map_builder_t *map, const hb_segment_properties_t *props) { map->add_bool_feature (HB_TAG('l','o','c','l')); /* The Indic specs do not require ccmp, but we apply it here since if * there is a use of it, it's typically at the beginning. */ map->add_bool_feature (HB_TAG('c','c','m','p')); map->add_gsub_pause (initial_reordering, NULL); for (unsigned int i = 0; i < ARRAY_LENGTH (indic_basic_features); i++) map->add_bool_feature (indic_basic_features[i].tag, indic_basic_features[i].is_global); map->add_gsub_pause (final_reordering, NULL); for (unsigned int i = 0; i < ARRAY_LENGTH (indic_other_features); i++) map->add_bool_feature (indic_other_features[i], true); } hb_ot_shape_normalization_mode_t _hb_ot_shape_complex_normalization_preference_indic (void) { /* We want split matras decomposed by the common shaping logic. */ return HB_OT_SHAPE_NORMALIZATION_MODE_DECOMPOSED; } void _hb_ot_shape_complex_setup_masks_indic (hb_ot_map_t *map, hb_buffer_t *buffer, hb_font_t *font) { HB_BUFFER_ALLOCATE_VAR (buffer, indic_category); HB_BUFFER_ALLOCATE_VAR (buffer, indic_position); /* We cannot setup masks here. We save information about characters * and setup masks later on in a pause-callback. */ unsigned int count = buffer->len; for (unsigned int i = 0; i < count; i++) { unsigned int type = get_indic_categories (buffer->info[i].codepoint); buffer->info[i].indic_category() = type & 0x0F; buffer->info[i].indic_position() = (type >> 4) & 7; if (buffer->info[i].indic_category() == OT_C) { buffer->info[i].indic_position() = consonant_position (buffer->info[i].codepoint); if (is_ra (buffer->info[i].codepoint)) buffer->info[i].indic_category() = OT_Ra; } else if (buffer->info[i].codepoint == 0x200C) buffer->info[i].indic_category() = OT_ZWNJ; else if (buffer->info[i].codepoint == 0x200D) buffer->info[i].indic_category() = OT_ZWJ; } } static int compare_indic_order (const hb_glyph_info_t *pa, const hb_glyph_info_t *pb) { int a = pa->indic_position(); int b = pb->indic_position(); return a < b ? -1 : a == b ? 0 : +1; } static void found_consonant_syllable (const hb_ot_map_t *map, hb_buffer_t *buffer, hb_mask_t *mask_array, unsigned int start, unsigned int end) { unsigned int i; hb_glyph_info_t *info = buffer->info; /* Comments from: * https://www.microsoft.com/typography/otfntdev/devanot/shaping.aspx */ /* 1. Find base consonant: * * The shaping engine finds the base consonant of the syllable, using the * following algorithm: starting from the end of the syllable, move backwards * until a consonant is found that does not have a below-base or post-base * form (post-base forms have to follow below-base forms), or that is not a * pre-base reordering Ra, or arrive at the first consonant. The consonant * stopped at will be the base. * * o If the syllable starts with Ra + Halant (in a script that has Reph) * and has more than one consonant, Ra is excluded from candidates for * base consonants. */ unsigned int base = end; /* -> starting from the end of the syllable, move backwards */ i = end; unsigned int limit = start; if (info[start].indic_category() == OT_Ra && start + 2 <= end) { limit += 2; base = start; }; do { i--; /* -> until a consonant is found */ if (is_consonant (info[i])) { /* -> that does not have a below-base or post-base form * (post-base forms have to follow below-base forms), */ if (info[i].indic_position() != POS_BELOW && info[i].indic_position() != POS_POST) { base = i; break; } /* -> or that is not a pre-base reordering Ra, * * TODO */ /* -> o If the syllable starts with Ra + Halant (in a script that has Reph) * and has more than one consonant, Ra is excluded from candidates for * base consonants. * * IMPLEMENTATION NOTES: * * We do this by adjusting limit accordingly before entering the loop. */ /* -> or arrive at the first consonant. The consonant stopped at will * be the base. */ base = i; } else if (is_joiner (info[i])) break; } while (i > limit); if (base < start) base = start; /* Just in case... */ /* 2. Decompose and reorder Matras: * * Each matra and any syllable modifier sign in the cluster are moved to the * appropriate position relative to the consonant(s) in the cluster. The * shaping engine decomposes two- or three-part matras into their constituent * parts before any repositioning. Matra characters are classified by which * consonant in a conjunct they have affinity for and are reordered to the * following positions: * * o Before first half form in the syllable * o After subjoined consonants * o After post-form consonant * o After main consonant (for above marks) * * IMPLEMENTATION NOTES: * * The normalize() routine has already decomposed matras for us, so we don't * need to worry about that. */ /* 3. Reorder marks to canonical order: * * Adjacent nukta and halant or nukta and vedic sign are always repositioned * if necessary, so that the nukta is first. * * IMPLEMENTATION NOTES: * * We don't need to do this: the normalize() routine already did this for us. */ /* Reorder characters */ for (i = start; i < base; i++) info[i].indic_position() = POS_PRE; info[base].indic_position() = POS_BASE; /* Handle beginning Ra */ if (start + 3 <= end && info[start].indic_category() == OT_Ra && info[start + 1].indic_category() == OT_H && !is_joiner (info[start + 2])) { info[start].indic_position() = POS_POST; info[start].mask = mask_array[RPHF]; } /* For old-style Indic script tags, move the first post-base Halant after * last consonant. */ if ((map->get_chosen_script (0) & 0x000000FF) != '2') { /* We should only do this for Indic scripts which have a version two I guess. */ for (i = base + 1; i < end; i++) if (info[i].indic_category() == OT_H) { unsigned int j; for (j = end - 1; j > i; j--) if ((FLAG (info[j].indic_category()) & (FLAG (OT_C) | FLAG (OT_Ra)))) break; if (j > i) { /* Move Halant to after last consonant. */ hb_glyph_info_t t = info[i]; memmove (&info[i], &info[i + 1], (j - i) * sizeof (info[0])); info[j] = t; } break; } } /* Attach ZWJ, ZWNJ, nukta, and halant to previous char to move with them. */ for (i = start + 1; i < end; i++) if ((FLAG (info[i].indic_category()) & (FLAG (OT_ZWNJ) | FLAG (OT_ZWJ) | FLAG (OT_N) | FLAG (OT_H)))) info[i].indic_position() = info[i - 1].indic_position(); /* We do bubble-sort, skip malicious clusters attempts */ if (end - start > 20) return; /* Sit tight, rock 'n roll! */ hb_bubble_sort (info + start, end - start, compare_indic_order); /* Setup masks now */ { hb_mask_t mask; /* Pre-base */ mask = mask_array[HALF] | mask_array[AKHN] | mask_array[CJCT]; for (i = start; i < base; i++) info[i].mask |= mask; /* Base */ mask = mask_array[AKHN] | mask_array[CJCT]; info[base].mask |= mask; /* Post-base */ mask = mask_array[BLWF] | mask_array[PSTF] | mask_array[CJCT]; for (i = base + 1; i < end; i++) info[i].mask |= mask; } /* Apply ZWJ/ZWNJ effects */ for (i = start + 1; i < end; i++) if (is_joiner (info[i])) { bool non_joiner = info[i].indic_category() == OT_ZWNJ; unsigned int j = i; do { j--; /* Reading the Unicode and OpenType specs, I think the following line * is correct, but this is not what the test suite expects currently. * The test suite has been drinking, not me... But disable while * investigating. */ //info[j].mask &= !mask_array[CJCT]; if (non_joiner) info[j].mask &= !mask_array[HALF]; } while (j > start && !is_consonant (info[j])); } } static void found_vowel_syllable (const hb_ot_map_t *map, hb_buffer_t *buffer, hb_mask_t *mask_array, unsigned int start, unsigned int end) { /* TODO * Not clear to me how this should work. Do the matras move to before the * independent vowel? No idea. */ } static void found_standalone_cluster (const hb_ot_map_t *map, hb_buffer_t *buffer, hb_mask_t *mask_array, unsigned int start, unsigned int end) { /* TODO * Easiest thing to do here is to convert the NBSP to consonant and * call found_consonant_syllable. */ } static void found_non_indic (const hb_ot_map_t *map, hb_buffer_t *buffer, hb_mask_t *mask_array, unsigned int start, unsigned int end) { /* Nothing to do right now. If we ever switch to using the output * buffer in the reordering process, we'd need to next_glyph() here. */ } #include "hb-ot-shape-complex-indic-machine.hh" static void remove_joiners (hb_buffer_t *buffer) { /* For now we remove joiners. However, Uniscbire seems to keep them * and output a zero-width space glyph for them. It is not clear to * me how that is supposed to interact with GSUB. */ buffer->clear_output (); unsigned int count = buffer->len; for (buffer->idx = 0; buffer->idx < count;) if (unlikely (is_joiner (buffer->info[buffer->idx]))) buffer->skip_glyph (); else buffer->next_glyph (); buffer->swap_buffers (); } static void initial_reordering (const hb_ot_map_t *map, hb_face_t *face, hb_buffer_t *buffer, void *user_data HB_UNUSED) { hb_mask_t mask_array[ARRAY_LENGTH (indic_basic_features)] = {0}; unsigned int num_masks = ARRAY_LENGTH (indic_basic_features); for (unsigned int i = 0; i < num_masks; i++) mask_array[i] = map->get_1_mask (indic_basic_features[i].tag); find_syllables (map, buffer, mask_array); remove_joiners (buffer); } static void final_reordering (const hb_ot_map_t *map, hb_face_t *face, hb_buffer_t *buffer, void *user_data HB_UNUSED) { /* 4. Final reordering: * * After the localized forms and basic shaping forms GSUB features have been * applied (see below), the shaping engine performs some final glyph * reordering before applying all the remaining font features to the entire * cluster. * * o Reorder matras: * * If a pre-base matra character had been reordered before applying basic * features, the glyph can be moved closer to the main consonant based on * whether half-forms had been formed. Actual position for the matra is * defined as “after last standalone halant glyph, after initial matra * position and before the main consonant”. If ZWJ or ZWNJ follow this * halant, position is moved after it. * * o Reorder reph: * * Reph’s original position is always at the beginning of the syllable, * (i.e. it is not reordered at the character reordering stage). However, * it will be reordered according to the basic-forms shaping results. * Possible positions for reph, depending on the script, are; after main, * before post-base consonant forms, and after post-base consonant forms. * * 1. If reph should be positioned after post-base consonant forms, * proceed to step 5. * * 2. If the reph repositioning class is not after post-base: target * position is after the first explicit halant glyph between the * first post-reph consonant and last main consonant. If ZWJ or ZWNJ * are following this halant, position is moved after it. If such * position is found, this is the target position. Otherwise, * proceed to the next step. * * Note: in old-implementation fonts, where classifications were * fixed in shaping engine, there was no case where reph position * will be found on this step. * * 3. If reph should be repositioned after the main consonant: from the * first consonant not ligated with main, or find the first * consonant that is not a potential pre-base reordering Ra. * * * 4. If reph should be positioned before post-base consonant, find * first post-base classified consonant not ligated with main. If no * consonant is found, the target position should be before the * first matra, syllable modifier sign or vedic sign. * * 5. If no consonant is found in steps 3 or 4, move reph to a position * immediately before the first post-base matra, syllable modifier * sign or vedic sign that has a reordering class after the intended * reph position. For example, if the reordering position for reph * is post-main, it will skip above-base matras that also have a * post-main position. * * 6. Otherwise, reorder reph to the end of the syllable. * * o Reorder pre-base reordering consonants: * * If a pre-base reordering consonant is found, reorder it according to * the following rules: * * 1. Only reorder a glyph produced by substitution during application * of the feature. (Note that a font may shape a Ra consonant with * the feature generally but block it in certain contexts.) * * 2. Try to find a target position the same way as for pre-base matra. * If it is found, reorder pre-base consonant glyph. * * 3. If position is not found, reorder immediately before main * consonant. */ /* TODO */ HB_BUFFER_DEALLOCATE_VAR (buffer, indic_category); HB_BUFFER_DEALLOCATE_VAR (buffer, indic_position); }