Edit
kc3-lang/harfbuzz/src/hb-ot-shaper-indic.cc
Behdad Esfahbod
- src/hb-ot-shaper-indic.cc
-
/* * Copyright © 2011,2012 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.hh" #ifndef HB_NO_OT_SHAPE #include "hb-ot-shaper-indic.hh" #include "hb-ot-shaper-indic-machine.hh" #include "hb-ot-shaper-vowel-constraints.hh" #include "hb-ot-layout.hh" /* * Indic shaper. */ static inline void set_indic_properties (hb_glyph_info_t &info) { hb_codepoint_t u = info.codepoint; unsigned int type = hb_indic_get_categories (u); info.indic_category() = (indic_category_t) (type & 0xFFu); info.indic_position() = (indic_position_t) (type >> 8); } static inline bool is_one_of (const hb_glyph_info_t &info, unsigned int flags) { /* If it ligated, all bets are off. */ if (_hb_glyph_info_ligated (&info)) return false; return !!(FLAG_UNSAFE (info.indic_category()) & flags); } /* Note: * * We treat Vowels and placeholders as if they were consonants. This is safe because Vowels * cannot happen in a consonant syllable. The plus side however is, we can call the * consonant syllable logic from the vowel syllable function and get it all right! * * Keep in sync with consonant_categories in the generator. */ #define CONSONANT_FLAGS_INDIC (FLAG (I_Cat(C)) | FLAG (I_Cat(CS)) | FLAG (I_Cat(Ra)) | FLAG (I_Cat(CM)) | FLAG (I_Cat(V)) | FLAG (I_Cat(PLACEHOLDER)) | FLAG (I_Cat(DOTTEDCIRCLE))) static inline bool is_consonant (const hb_glyph_info_t &info) { return is_one_of (info, CONSONANT_FLAGS_INDIC); } #define JOINER_FLAGS (FLAG (I_Cat(ZWJ)) | FLAG (I_Cat(ZWNJ))) static inline bool is_joiner (const hb_glyph_info_t &info) { return is_one_of (info, JOINER_FLAGS); } static inline bool is_halant (const hb_glyph_info_t &info) { return is_one_of (info, FLAG (I_Cat(H))); } struct hb_indic_would_substitute_feature_t { void init (const hb_ot_map_t *map, hb_tag_t feature_tag, bool zero_context_) { zero_context = zero_context_; lookups = map->get_stage_lookups (0/*GSUB*/, map->get_feature_stage (0/*GSUB*/, feature_tag)); } bool would_substitute (const hb_codepoint_t *glyphs, unsigned int glyphs_count, hb_face_t *face) const { for (const auto &lookup : lookups) if (hb_ot_layout_lookup_would_substitute (face, lookup.index, glyphs, glyphs_count, zero_context)) return true; return false; } private: hb_array_t<const hb_ot_map_t::lookup_map_t> lookups; bool zero_context; }; /* * Indic configurations. Note that we do not want to keep every single script-specific * behavior in these tables necessarily. This should mainly be used for per-script * properties that are cheaper keeping here, than in the code. Ie. if, say, one and * only one script has an exception, that one script can be if'ed directly in the code, * instead of adding a new flag in these structs. */ enum reph_position_t { REPH_POS_AFTER_MAIN = POS_AFTER_MAIN, REPH_POS_BEFORE_SUB = POS_BEFORE_SUB, REPH_POS_AFTER_SUB = POS_AFTER_SUB, REPH_POS_BEFORE_POST = POS_BEFORE_POST, REPH_POS_AFTER_POST = POS_AFTER_POST }; enum reph_mode_t { REPH_MODE_IMPLICIT, /* Reph formed out of initial Ra,H sequence. */ REPH_MODE_EXPLICIT, /* Reph formed out of initial Ra,H,ZWJ sequence. */ REPH_MODE_LOG_REPHA /* Encoded Repha character, needs reordering. */ }; enum blwf_mode_t { BLWF_MODE_PRE_AND_POST, /* Below-forms feature applied to pre-base and post-base. */ BLWF_MODE_POST_ONLY /* Below-forms feature applied to post-base only. */ }; struct indic_config_t { hb_script_t script; bool has_old_spec; hb_codepoint_t virama; reph_position_t reph_pos; reph_mode_t reph_mode; blwf_mode_t blwf_mode; }; static const indic_config_t indic_configs[] = { /* Default. Should be first. */ {HB_SCRIPT_INVALID, false, 0,REPH_POS_BEFORE_POST,REPH_MODE_IMPLICIT, BLWF_MODE_PRE_AND_POST}, {HB_SCRIPT_DEVANAGARI,true, 0x094Du,REPH_POS_BEFORE_POST,REPH_MODE_IMPLICIT, BLWF_MODE_PRE_AND_POST}, {HB_SCRIPT_BENGALI, true, 0x09CDu,REPH_POS_AFTER_SUB, REPH_MODE_IMPLICIT, BLWF_MODE_PRE_AND_POST}, {HB_SCRIPT_GURMUKHI, true, 0x0A4Du,REPH_POS_BEFORE_SUB, REPH_MODE_IMPLICIT, BLWF_MODE_PRE_AND_POST}, {HB_SCRIPT_GUJARATI, true, 0x0ACDu,REPH_POS_BEFORE_POST,REPH_MODE_IMPLICIT, BLWF_MODE_PRE_AND_POST}, {HB_SCRIPT_ORIYA, true, 0x0B4Du,REPH_POS_AFTER_MAIN, REPH_MODE_IMPLICIT, BLWF_MODE_PRE_AND_POST}, {HB_SCRIPT_TAMIL, true, 0x0BCDu,REPH_POS_AFTER_POST, REPH_MODE_IMPLICIT, BLWF_MODE_PRE_AND_POST}, {HB_SCRIPT_TELUGU, true, 0x0C4Du,REPH_POS_AFTER_POST, REPH_MODE_EXPLICIT, BLWF_MODE_POST_ONLY}, {HB_SCRIPT_KANNADA, true, 0x0CCDu,REPH_POS_AFTER_POST, REPH_MODE_IMPLICIT, BLWF_MODE_POST_ONLY}, {HB_SCRIPT_MALAYALAM, true, 0x0D4Du,REPH_POS_AFTER_MAIN, REPH_MODE_LOG_REPHA,BLWF_MODE_PRE_AND_POST}, }; static const hb_ot_map_feature_t indic_features[] = { /* * Basic features. * These features are applied in order, one at a time, after initial_reordering, * constrained to the syllable. */ {HB_TAG('n','u','k','t'), F_GLOBAL_MANUAL_JOINERS | F_PER_SYLLABLE}, {HB_TAG('a','k','h','n'), F_GLOBAL_MANUAL_JOINERS | F_PER_SYLLABLE}, {HB_TAG('r','p','h','f'), F_MANUAL_JOINERS | F_PER_SYLLABLE}, {HB_TAG('r','k','r','f'), F_GLOBAL_MANUAL_JOINERS | F_PER_SYLLABLE}, {HB_TAG('p','r','e','f'), F_MANUAL_JOINERS | F_PER_SYLLABLE}, {HB_TAG('b','l','w','f'), F_MANUAL_JOINERS | F_PER_SYLLABLE}, {HB_TAG('a','b','v','f'), F_MANUAL_JOINERS | F_PER_SYLLABLE}, {HB_TAG('h','a','l','f'), F_MANUAL_JOINERS | F_PER_SYLLABLE}, {HB_TAG('p','s','t','f'), F_MANUAL_JOINERS | F_PER_SYLLABLE}, {HB_TAG('v','a','t','u'), F_GLOBAL_MANUAL_JOINERS | F_PER_SYLLABLE}, {HB_TAG('c','j','c','t'), F_GLOBAL_MANUAL_JOINERS | F_PER_SYLLABLE}, /* * Other features. * These features are applied all at once, after final_reordering, constrained * to the syllable. * Default Bengali font in Windows for example has intermixed * lookups for init,pres,abvs,blws features. */ {HB_TAG('i','n','i','t'), F_MANUAL_JOINERS | F_PER_SYLLABLE}, {HB_TAG('p','r','e','s'), F_GLOBAL_MANUAL_JOINERS | F_PER_SYLLABLE}, {HB_TAG('a','b','v','s'), F_GLOBAL_MANUAL_JOINERS | F_PER_SYLLABLE}, {HB_TAG('b','l','w','s'), F_GLOBAL_MANUAL_JOINERS | F_PER_SYLLABLE}, {HB_TAG('p','s','t','s'), F_GLOBAL_MANUAL_JOINERS | F_PER_SYLLABLE}, {HB_TAG('h','a','l','n'), F_GLOBAL_MANUAL_JOINERS | F_PER_SYLLABLE}, }; /* * Must be in the same order as the indic_features array. */ enum { _INDIC_NUKT, _INDIC_AKHN, INDIC_RPHF, _INDIC_RKRF, INDIC_PREF, INDIC_BLWF, INDIC_ABVF, INDIC_HALF, INDIC_PSTF, _INDIC_VATU, _INDIC_CJCT, INDIC_INIT, _INDIC_PRES, _INDIC_ABVS, _INDIC_BLWS, _INDIC_PSTS, _INDIC_HALN, INDIC_NUM_FEATURES, INDIC_BASIC_FEATURES = INDIC_INIT, /* Don't forget to update this! */ }; static bool setup_syllables_indic (const hb_ot_shape_plan_t *plan, hb_font_t *font, hb_buffer_t *buffer); static bool initial_reordering_indic (const hb_ot_shape_plan_t *plan, hb_font_t *font, hb_buffer_t *buffer); static bool final_reordering_indic (const hb_ot_shape_plan_t *plan, hb_font_t *font, hb_buffer_t *buffer); static void collect_features_indic (hb_ot_shape_planner_t *plan) { hb_ot_map_builder_t *map = &plan->map; /* Do this before any lookups have been applied. */ map->add_gsub_pause (setup_syllables_indic); map->enable_feature (HB_TAG('l','o','c','l'), F_PER_SYLLABLE); /* 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->enable_feature (HB_TAG('c','c','m','p'), F_PER_SYLLABLE); unsigned int i = 0; map->add_gsub_pause (initial_reordering_indic); for (; i < INDIC_BASIC_FEATURES; i++) { map->add_feature (indic_features[i]); map->add_gsub_pause (nullptr); } map->add_gsub_pause (final_reordering_indic); for (; i < INDIC_NUM_FEATURES; i++) map->add_feature (indic_features[i]); } static void override_features_indic (hb_ot_shape_planner_t *plan) { plan->map.disable_feature (HB_TAG('l','i','g','a')); plan->map.add_gsub_pause (hb_syllabic_clear_var); // Don't need syllables anymore, use stop to free buffer var } struct indic_shape_plan_t { bool load_virama_glyph (hb_font_t *font, hb_codepoint_t *pglyph) const { hb_codepoint_t glyph = virama_glyph; if (unlikely (glyph == (hb_codepoint_t) -1)) { if (!config->virama || !font->get_nominal_glyph (config->virama, &glyph)) glyph = 0; /* Technically speaking, the spec says we should apply 'locl' to virama too. * Maybe one day... */ /* Our get_nominal_glyph() function needs a font, so we can't get the virama glyph * during shape planning... Instead, overwrite it here. */ virama_glyph = (int) glyph; } *pglyph = glyph; return glyph != 0; } const indic_config_t *config; bool is_old_spec; #ifndef HB_NO_UNISCRIBE_BUG_COMPATIBLE bool uniscribe_bug_compatible; #else static constexpr bool uniscribe_bug_compatible = false; #endif mutable hb_atomic_t<hb_codepoint_t> virama_glyph; hb_indic_would_substitute_feature_t rphf; hb_indic_would_substitute_feature_t pref; hb_indic_would_substitute_feature_t blwf; hb_indic_would_substitute_feature_t pstf; hb_indic_would_substitute_feature_t vatu; hb_mask_t mask_array[INDIC_NUM_FEATURES]; }; static void * data_create_indic (const hb_ot_shape_plan_t *plan) { indic_shape_plan_t *indic_plan = (indic_shape_plan_t *) hb_calloc (1, sizeof (indic_shape_plan_t)); if (unlikely (!indic_plan)) return nullptr; indic_plan->config = &indic_configs[0]; for (unsigned int i = 1; i < ARRAY_LENGTH (indic_configs); i++) if (plan->props.script == indic_configs[i].script) { indic_plan->config = &indic_configs[i]; break; } indic_plan->is_old_spec = indic_plan->config->has_old_spec && ((plan->map.chosen_script[0] & 0x000000FFu) != '2'); #ifndef HB_NO_UNISCRIBE_BUG_COMPATIBLE indic_plan->uniscribe_bug_compatible = hb_options ().uniscribe_bug_compatible; #endif indic_plan->virama_glyph = -1; /* Use zero-context would_substitute() matching for new-spec of the main * Indic scripts, and scripts with one spec only, but not for old-specs. * The new-spec for all dual-spec scripts says zero-context matching happens. * * However, testing with Malayalam shows that old and new spec both allow * context. Testing with Bengali new-spec however shows that it doesn't. * So, the heuristic here is the way it is. It should *only* be changed, * as we discover more cases of what Windows does. DON'T TOUCH OTHERWISE. */ bool zero_context = !indic_plan->is_old_spec && plan->props.script != HB_SCRIPT_MALAYALAM; indic_plan->rphf.init (&plan->map, HB_TAG('r','p','h','f'), zero_context); indic_plan->pref.init (&plan->map, HB_TAG('p','r','e','f'), zero_context); indic_plan->blwf.init (&plan->map, HB_TAG('b','l','w','f'), zero_context); indic_plan->pstf.init (&plan->map, HB_TAG('p','s','t','f'), zero_context); indic_plan->vatu.init (&plan->map, HB_TAG('v','a','t','u'), zero_context); for (unsigned int i = 0; i < ARRAY_LENGTH (indic_plan->mask_array); i++) indic_plan->mask_array[i] = (indic_features[i].flags & F_GLOBAL) ? 0 : plan->map.get_1_mask (indic_features[i].tag); return indic_plan; } static void data_destroy_indic (void *data) { hb_free (data); } static indic_position_t consonant_position_from_face (const indic_shape_plan_t *indic_plan, const hb_codepoint_t consonant, const hb_codepoint_t virama, hb_face_t *face) { /* For old-spec, the order of glyphs is Consonant,Virama, * whereas for new-spec, it's Virama,Consonant. However, * some broken fonts (like Free Sans) simply copied lookups * from old-spec to new-spec without modification. * And oddly enough, Uniscribe seems to respect those lookups. * Eg. in the sequence U+0924,U+094D,U+0930, Uniscribe finds * base at 0. The font however, only has lookups matching * 930,94D in 'blwf', not the expected 94D,930 (with new-spec * table). As such, we simply match both sequences. Seems * to work. * * Vatu is done as well, for: * https://github.com/harfbuzz/harfbuzz/issues/1587 */ hb_codepoint_t glyphs[3] = {virama, consonant, virama}; if (indic_plan->blwf.would_substitute (glyphs , 2, face) || indic_plan->blwf.would_substitute (glyphs+1, 2, face) || indic_plan->vatu.would_substitute (glyphs , 2, face) || indic_plan->vatu.would_substitute (glyphs+1, 2, face)) return POS_BELOW_C; if (indic_plan->pstf.would_substitute (glyphs , 2, face) || indic_plan->pstf.would_substitute (glyphs+1, 2, face)) return POS_POST_C; if (indic_plan->pref.would_substitute (glyphs , 2, face) || indic_plan->pref.would_substitute (glyphs+1, 2, face)) return POS_POST_C; return POS_BASE_C; } static void setup_masks_indic (const hb_ot_shape_plan_t *plan HB_UNUSED, hb_buffer_t *buffer, hb_font_t *font HB_UNUSED) { 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; hb_glyph_info_t *info = buffer->info; for (unsigned int i = 0; i < count; i++) set_indic_properties (info[i]); } static bool setup_syllables_indic (const hb_ot_shape_plan_t *plan HB_UNUSED, hb_font_t *font HB_UNUSED, hb_buffer_t *buffer) { HB_BUFFER_ALLOCATE_VAR (buffer, syllable); find_syllables_indic (buffer); foreach_syllable (buffer, start, end) buffer->unsafe_to_break (start, end); return false; } 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 (int) a - (int) b; } static void update_consonant_positions_indic (const hb_ot_shape_plan_t *plan, hb_font_t *font, hb_buffer_t *buffer) { const indic_shape_plan_t *indic_plan = (const indic_shape_plan_t *) plan->data; hb_codepoint_t virama; if (indic_plan->load_virama_glyph (font, &virama)) { hb_face_t *face = font->face; unsigned int count = buffer->len; hb_glyph_info_t *info = buffer->info; for (unsigned int i = 0; i < count; i++) if (info[i].indic_position() == POS_BASE_C) { hb_codepoint_t consonant = info[i].codepoint; info[i].indic_position() = consonant_position_from_face (indic_plan, consonant, virama, face); } } } /* Rules from: * https://docs.microsqoft.com/en-us/typography/script-development/devanagari */ static void initial_reordering_consonant_syllable (const hb_ot_shape_plan_t *plan, hb_face_t *face, hb_buffer_t *buffer, unsigned int start, unsigned int end) { const indic_shape_plan_t *indic_plan = (const indic_shape_plan_t *) plan->data; hb_glyph_info_t *info = buffer->info; /* https://github.com/harfbuzz/harfbuzz/issues/435#issuecomment-335560167 * // For compatibility with legacy usage in Kannada, * // Ra+h+ZWJ must behave like Ra+ZWJ+h... */ if (buffer->props.script == HB_SCRIPT_KANNADA && start + 3 <= end && is_one_of (info[start ], FLAG (I_Cat(Ra))) && is_one_of (info[start+1], FLAG (I_Cat(H))) && is_one_of (info[start+2], FLAG (I_Cat(ZWJ)))) { buffer->merge_clusters (start+1, start+3); hb_swap (info[start+1], info[start+2]); } /* 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; bool has_reph = false; { /* -> 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 limit = start; if (indic_plan->mask_array[INDIC_RPHF] && start + 3 <= end && ( (indic_plan->config->reph_mode == REPH_MODE_IMPLICIT && !is_joiner (info[start + 2])) || (indic_plan->config->reph_mode == REPH_MODE_EXPLICIT && info[start + 2].indic_category() == I_Cat(ZWJ)) )) { /* See if it matches the 'rphf' feature. */ hb_codepoint_t glyphs[3] = {info[start].codepoint, info[start + 1].codepoint, indic_plan->config->reph_mode == REPH_MODE_EXPLICIT ? info[start + 2].codepoint : 0}; if (indic_plan->rphf.would_substitute (glyphs, 2, face) || (indic_plan->config->reph_mode == REPH_MODE_EXPLICIT && indic_plan->rphf.would_substitute (glyphs, 3, face))) { limit += 2; while (limit < end && is_joiner (info[limit])) limit++; base = start; has_reph = true; } } else if (indic_plan->config->reph_mode == REPH_MODE_LOG_REPHA && info[start].indic_category() == I_Cat(Repha)) { limit += 1; while (limit < end && is_joiner (info[limit])) limit++; base = start; has_reph = true; } { /* -> starting from the end of the syllable, move backwards */ unsigned int i = end; bool seen_below = false; 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_C && (info[i].indic_position() != POS_POST_C || seen_below)) { base = i; break; } if (info[i].indic_position() == POS_BELOW_C) seen_below = true; /* -> or that is not a pre-base-reordering Ra, * * IMPLEMENTATION NOTES: * * Our pre-base-reordering Ra's are marked POS_POST_C, so will be skipped * by the logic above already. */ /* -> or arrive at the first consonant. The consonant stopped at will * be the base. */ base = i; } else { /* A ZWJ after a Halant stops the base search, and requests an explicit * half form. * A ZWJ before a Halant, requests a subjoined form instead, and hence * search continues. This is particularly important for Bengali * sequence Ra,H,Ya that should form Ya-Phalaa by subjoining Ya. */ if (start < i && info[i].indic_category() == I_Cat(ZWJ) && info[i - 1].indic_category() == I_Cat(H)) break; } } while (i > limit); } /* -> 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. * * Only do this for unforced Reph. (ie. not for Ra,H,ZWJ. */ if (has_reph && base == start && limit - base <= 2) { /* Have no other consonant, so Reph is not formed and Ra becomes base. */ has_reph = false; } } /* 2. Decompose and reorder Matras: * * Each matra and any syllable modifier sign in the syllable are moved to the * appropriate position relative to the consonant(s) in the syllable. 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 (unsigned int i = start; i < base; i++) info[i].indic_position() = hb_min (POS_PRE_C, (indic_position_t) info[i].indic_position()); if (base < end) info[base].indic_position() = POS_BASE_C; /* Handle beginning Ra */ if (has_reph) info[start].indic_position() = POS_RA_TO_BECOME_REPH; /* For old-style Indic script tags, move the first post-base Halant after * last consonant. * * Reports suggest that in some scripts Uniscribe does this only if there * is *not* a Halant after last consonant already. We know that is the * case for Kannada, while it reorders unconditionally in other scripts, * eg. Malayalam, Bengali, and Devanagari. We don't currently know about * other scripts, so we block Kannada. * * Kannada test case: * U+0C9A,U+0CCD,U+0C9A,U+0CCD * With some versions of Lohit Kannada. * https://bugs.freedesktop.org/show_bug.cgi?id=59118 * * Malayalam test case: * U+0D38,U+0D4D,U+0D31,U+0D4D,U+0D31,U+0D4D * With lohit-ttf-20121122/Lohit-Malayalam.ttf * * Bengali test case: * U+0998,U+09CD,U+09AF,U+09CD * With Windows XP vrinda.ttf * https://github.com/harfbuzz/harfbuzz/issues/1073 * * Devanagari test case: * U+091F,U+094D,U+0930,U+094D * With chandas.ttf * https://github.com/harfbuzz/harfbuzz/issues/1071 */ if (indic_plan->is_old_spec) { bool disallow_double_halants = buffer->props.script == HB_SCRIPT_KANNADA; for (unsigned int i = base + 1; i < end; i++) if (info[i].indic_category() == I_Cat(H)) { unsigned int j; for (j = end - 1; j > i; j--) if (is_consonant (info[j]) || (disallow_double_halants && info[j].indic_category() == I_Cat(H))) break; if (info[j].indic_category() != I_Cat(H) && 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 misc marks to previous char to move with them. */ { indic_position_t last_pos = POS_START; for (unsigned int i = start; i < end; i++) { if ((FLAG_UNSAFE (info[i].indic_category()) & (JOINER_FLAGS | FLAG (I_Cat(N)) | FLAG (I_Cat(RS)) | FLAG (I_Cat(CM)) | FLAG (I_Cat(H))))) { info[i].indic_position() = last_pos; if (unlikely (info[i].indic_category() == I_Cat(H) && info[i].indic_position() == POS_PRE_M)) { /* * Uniscribe doesn't move the Halant with Left Matra. * TEST: U+092B,U+093F,U+094D * We follow. */ for (unsigned int j = i; j > start; j--) if (info[j - 1].indic_position() != POS_PRE_M) { info[i].indic_position() = info[j - 1].indic_position(); break; } } } else if (info[i].indic_position() != POS_SMVD) { if (info[i].indic_category() == I_Cat(MPst) && i > start && info[i - 1].indic_category() == I_Cat(SM)) info[i - 1].indic_position() = info[i].indic_position(); last_pos = (indic_position_t) info[i].indic_position(); } } } /* For post-base consonants let them own anything before them * since the last consonant or matra. */ { unsigned int last = base; for (unsigned int i = base + 1; i < end; i++) if (is_consonant (info[i])) { for (unsigned int j = last + 1; j < i; j++) if (info[j].indic_position() < POS_SMVD) info[j].indic_position() = info[i].indic_position(); last = i; } else if (FLAG_UNSAFE (info[i].indic_category()) & (FLAG (I_Cat(M)) | FLAG (I_Cat(MPst)))) last = i; } { /* Use syllable() for sort accounting temporarily. */ unsigned int syllable = info[start].syllable(); for (unsigned int i = start; i < end; i++) info[i].syllable() = i - start; /* Sit tight, rock 'n roll! */ hb_stable_sort (info + start, end - start, compare_indic_order); /* Find base again; also flip left-matra sequence. */ unsigned first_left_matra = end; unsigned last_left_matra = end; base = end; for (unsigned int i = start; i < end; i++) { if (info[i].indic_position() == POS_BASE_C) { base = i; break; } else if (info[i].indic_position() == POS_PRE_M) { if (first_left_matra == end) first_left_matra = i; last_left_matra = i; } } /* https://github.com/harfbuzz/harfbuzz/issues/3863 */ if (first_left_matra < last_left_matra) { /* No need to merge clusters, handled later. */ buffer->reverse_range (first_left_matra, last_left_matra + 1); /* Reverse back nuktas, etc. */ unsigned i = first_left_matra; for (unsigned j = i; j <= last_left_matra; j++) if (FLAG_UNSAFE (info[j].indic_category()) & (FLAG (I_Cat(M)) | FLAG (I_Cat(MPst)))) { buffer->reverse_range (i, j + 1); i = j + 1; } } /* Things are out-of-control for post base positions, they may shuffle * around like crazy. In old-spec mode, we move halants around, so in * that case merge all clusters after base. Otherwise, check the sort * order and merge as needed. * For pre-base stuff, we handle cluster issues in final reordering. * * We could use buffer->sort() for this, if there was no special * reordering of pre-base stuff happening later... * We don't want to merge_clusters all of that, which buffer->sort() * would. Here's a concrete example: * * Assume there's a pre-base consonant and explicit Halant before base, * followed by a prebase-reordering (left) Matra: * * C,H,ZWNJ,B,M * * At this point in reordering we would have: * * M,C,H,ZWNJ,B * * whereas in final reordering we will bring the Matra closer to Base: * * C,H,ZWNJ,M,B * * That's why we don't want to merge-clusters anything before the Base * at this point. But if something moved from after Base to before it, * we should merge clusters from base to them. In final-reordering, we * only move things around before base, and merge-clusters up to base. * These two merge-clusters from the two sides of base will interlock * to merge things correctly. See: * https://github.com/harfbuzz/harfbuzz/issues/2272 */ if (indic_plan->is_old_spec || end - start > 127) buffer->merge_clusters (base, end); else { /* Note! syllable() is a one-byte field. */ for (unsigned int i = base; i < end; i++) if (info[i].syllable() != 255) { unsigned int min = i; unsigned int max = i; unsigned int j = start + info[i].syllable(); while (j != i) { min = hb_min (min, j); max = hb_max (max, j); unsigned int next = start + info[j].syllable(); info[j].syllable() = 255; /* So we don't process j later again. */ j = next; } buffer->merge_clusters (hb_max (base, min), max + 1); } } /* Put syllable back in. */ for (unsigned int i = start; i < end; i++) info[i].syllable() = syllable; } /* Setup masks now */ { hb_mask_t mask; /* Reph */ for (unsigned int i = start; i < end && info[i].indic_position() == POS_RA_TO_BECOME_REPH; i++) info[i].mask |= indic_plan->mask_array[INDIC_RPHF]; /* Pre-base */ mask = indic_plan->mask_array[INDIC_HALF]; if (!indic_plan->is_old_spec && indic_plan->config->blwf_mode == BLWF_MODE_PRE_AND_POST) mask |= indic_plan->mask_array[INDIC_BLWF]; for (unsigned int i = start; i < base; i++) info[i].mask |= mask; /* Base */ mask = 0; if (base < end) info[base].mask |= mask; /* Post-base */ mask = indic_plan->mask_array[INDIC_BLWF] | indic_plan->mask_array[INDIC_ABVF] | indic_plan->mask_array[INDIC_PSTF]; for (unsigned int i = base + 1; i < end; i++) info[i].mask |= mask; } if (indic_plan->is_old_spec && buffer->props.script == HB_SCRIPT_DEVANAGARI) { /* Old-spec eye-lash Ra needs special handling. From the * spec: * * "The feature 'below-base form' is applied to consonants * having below-base forms and following the base consonant. * The exception is vattu, which may appear below half forms * as well as below the base glyph. The feature 'below-base * form' will be applied to all such occurrences of Ra as well." * * Test case: U+0924,U+094D,U+0930,U+094d,U+0915 * with Sanskrit 2003 font. * * However, note that Ra,Halant,ZWJ is the correct way to * request eyelash form of Ra, so we wouldbn't inhibit it * in that sequence. * * Test case: U+0924,U+094D,U+0930,U+094d,U+200D,U+0915 */ for (unsigned int i = start; i + 1 < base; i++) if (info[i ].indic_category() == I_Cat(Ra) && info[i+1].indic_category() == I_Cat(H) && (i + 2 == base || info[i+2].indic_category() != I_Cat(ZWJ))) { info[i ].mask |= indic_plan->mask_array[INDIC_BLWF]; info[i+1].mask |= indic_plan->mask_array[INDIC_BLWF]; } } unsigned int pref_len = 2; if (indic_plan->mask_array[INDIC_PREF] && base + pref_len < end) { /* Find a Halant,Ra sequence and mark it for pre-base-reordering processing. */ for (unsigned int i = base + 1; i + pref_len - 1 < end; i++) { hb_codepoint_t glyphs[2]; for (unsigned int j = 0; j < pref_len; j++) glyphs[j] = info[i + j].codepoint; if (indic_plan->pref.would_substitute (glyphs, pref_len, face)) { for (unsigned int j = 0; j < pref_len; j++) info[i++].mask |= indic_plan->mask_array[INDIC_PREF]; break; } } } /* Apply ZWJ/ZWNJ effects */ for (unsigned int i = start + 1; i < end; i++) if (is_joiner (info[i])) { bool non_joiner = info[i].indic_category() == I_Cat(ZWNJ); unsigned int j = i; do { j--; /* ZWJ/ZWNJ should disable CJCT. They do that by simply * being there, since we don't skip them for the CJCT * feature (ie. F_MANUAL_ZWJ) */ /* A ZWNJ disables HALF. */ if (non_joiner) info[j].mask &= ~indic_plan->mask_array[INDIC_HALF]; } while (j > start && !is_consonant (info[j])); } } static void initial_reordering_standalone_cluster (const hb_ot_shape_plan_t *plan, hb_face_t *face, hb_buffer_t *buffer, unsigned int start, unsigned int end) { /* We treat placeholder/dotted-circle as if they are consonants, so we * should just chain. Only if not in compatibility mode that is... */ const indic_shape_plan_t *indic_plan = (const indic_shape_plan_t *) plan->data; if (indic_plan->uniscribe_bug_compatible) { /* For dotted-circle, this is what Uniscribe does: * If dotted-circle is the last glyph, it just does nothing. * Ie. It doesn't form Reph. */ if (buffer->info[end - 1].indic_category() == I_Cat(DOTTEDCIRCLE)) return; } initial_reordering_consonant_syllable (plan, face, buffer, start, end); } static void initial_reordering_syllable_indic (const hb_ot_shape_plan_t *plan, hb_face_t *face, hb_buffer_t *buffer, unsigned int start, unsigned int end) { indic_syllable_type_t syllable_type = (indic_syllable_type_t) (buffer->info[start].syllable() & 0x0F); switch (syllable_type) { case indic_vowel_syllable: /* We made the vowels look like consonants. So let's call the consonant logic! */ case indic_consonant_syllable: initial_reordering_consonant_syllable (plan, face, buffer, start, end); break; case indic_broken_cluster: /* We already inserted dotted-circles, so just call the standalone_cluster. */ case indic_standalone_cluster: initial_reordering_standalone_cluster (plan, face, buffer, start, end); break; case indic_symbol_cluster: case indic_non_indic_cluster: break; } } static bool initial_reordering_indic (const hb_ot_shape_plan_t *plan, hb_font_t *font, hb_buffer_t *buffer) { bool ret = false; if (!buffer->message (font, "start reordering indic initial")) return ret; update_consonant_positions_indic (plan, font, buffer); if (hb_syllabic_insert_dotted_circles (font, buffer, indic_broken_cluster, I_Cat(DOTTEDCIRCLE), I_Cat(Repha), POS_END)) ret = true; foreach_syllable (buffer, start, end) initial_reordering_syllable_indic (plan, font->face, buffer, start, end); (void) buffer->message (font, "end reordering indic initial"); return ret; } static void final_reordering_syllable_indic (const hb_ot_shape_plan_t *plan, hb_buffer_t *buffer, unsigned int start, unsigned int end) { const indic_shape_plan_t *indic_plan = (const indic_shape_plan_t *) plan->data; hb_glyph_info_t *info = buffer->info; /* This function relies heavily on halant glyphs. Lots of ligation * and possibly multiple substitutions happened prior to this * phase, and that might have messed up our properties. Recover * from a particular case of that where we're fairly sure that a * class of I_Cat(H) is desired but has been lost. */ /* We don't call load_virama_glyph(), since we know it's already * loaded. */ hb_codepoint_t virama_glyph = indic_plan->virama_glyph; if (virama_glyph) { for (unsigned int i = start; i < end; i++) if (info[i].codepoint == virama_glyph && _hb_glyph_info_ligated (&info[i]) && _hb_glyph_info_multiplied (&info[i])) { /* This will make sure that this glyph passes is_halant() test. */ info[i].indic_category() = I_Cat(H); _hb_glyph_info_clear_ligated_and_multiplied (&info[i]); } } /* 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 * syllable. */ bool try_pref = !!indic_plan->mask_array[INDIC_PREF]; /* Find base again */ unsigned int base; for (base = start; base < end; base++) if (info[base].indic_position() >= POS_BASE_C) { if (try_pref && base + 1 < end) { for (unsigned int i = base + 1; i < end; i++) if ((info[i].mask & indic_plan->mask_array[INDIC_PREF]) != 0) { if (!(_hb_glyph_info_substituted (&info[i]) && _hb_glyph_info_ligated_and_didnt_multiply (&info[i]))) { /* Ok, this was a 'pref' candidate but didn't form any. * Base is around here... */ base = i; while (base < end && is_halant (info[base])) base++; if (base < end) info[base].indic_position() = POS_BASE_C; try_pref = false; } break; } if (base == end) break; } /* For Malayalam, skip over unformed below- (but NOT post-) forms. */ if (buffer->props.script == HB_SCRIPT_MALAYALAM) { for (unsigned int i = base + 1; i < end; i++) { while (i < end && is_joiner (info[i])) i++; if (i == end || !is_halant (info[i])) break; i++; /* Skip halant. */ while (i < end && is_joiner (info[i])) i++; if (i < end && is_consonant (info[i]) && info[i].indic_position() == POS_BELOW_C) { base = i; info[base].indic_position() = POS_BASE_C; } } } if (start < base && info[base].indic_position() > POS_BASE_C) base--; break; } if (base == end && start < base && is_one_of (info[base - 1], FLAG (I_Cat(ZWJ)))) base--; if (base < end) while (start < base && is_one_of (info[base], (FLAG (I_Cat(N)) | FLAG (I_Cat(H))))) base--; /* 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. * * IMPLEMENTATION NOTES: * * It looks like the last sentence is wrong. Testing, with Windows 7 Uniscribe * and Devanagari shows that the behavior is best described as: * * "If ZWJ follows this halant, matra is NOT repositioned after this halant. * If ZWNJ follows this halant, position is moved after it." * * Test case, with Adobe Devanagari or Nirmala UI: * * U+091F,U+094D,U+200C,U+092F,U+093F * (Matra moves to the middle, after ZWNJ.) * * U+091F,U+094D,U+200D,U+092F,U+093F * (Matra does NOT move, stays to the left.) * * https://github.com/harfbuzz/harfbuzz/issues/1070 */ if (start + 1 < end && start < base) /* Otherwise there can't be any pre-base matra characters. */ { /* If we lost track of base, alas, position before last thingy. */ unsigned int new_pos = base == end ? base - 2 : base - 1; /* Malayalam / Tamil do not have "half" forms or explicit virama forms. * The glyphs formed by 'half' are Chillus or ligated explicit viramas. * We want to position matra after them. */ if (buffer->props.script != HB_SCRIPT_MALAYALAM && buffer->props.script != HB_SCRIPT_TAMIL) { search: while (new_pos > start && !(is_one_of (info[new_pos], (FLAG (I_Cat(M)) | FLAG (I_Cat(MPst)) | FLAG (I_Cat(H)))))) new_pos--; /* If we found no Halant we are done. * Otherwise only proceed if the Halant does * not belong to the Matra itself! */ if (is_halant (info[new_pos]) && info[new_pos].indic_position() != POS_PRE_M) { #if 0 // See comment above /* -> If ZWJ or ZWNJ follow this halant, position is moved after it. */ if (new_pos + 1 < end && is_joiner (info[new_pos + 1])) new_pos++; #endif if (new_pos + 1 < end) { /* -> If ZWJ follows this halant, matra is NOT repositioned after this halant. */ if (info[new_pos + 1].indic_category() == I_Cat(ZWJ)) { /* Keep searching. */ if (new_pos > start) { new_pos--; goto search; } } /* -> If ZWNJ follows this halant, position is moved after it. * * IMPLEMENTATION NOTES: * * This is taken care of by the state-machine. A Halant,ZWNJ is a terminating * sequence for a consonant syllable; any pre-base matras occurring after it * will belong to the subsequent syllable. */ } } else new_pos = start; /* No move. */ } if (start < new_pos && info[new_pos].indic_position () != POS_PRE_M) { /* Now go see if there's actually any matras... */ for (unsigned int i = new_pos; i > start; i--) if (info[i - 1].indic_position () == POS_PRE_M) { unsigned int old_pos = i - 1; if (old_pos < base && base <= new_pos) /* Shouldn't actually happen. */ base--; hb_glyph_info_t tmp = info[old_pos]; memmove (&info[old_pos], &info[old_pos + 1], (new_pos - old_pos) * sizeof (info[0])); info[new_pos] = tmp; /* Note: this merge_clusters() is intentionally *after* the reordering. * Indic matra reordering is special and tricky... */ buffer->merge_clusters (new_pos, hb_min (end, base + 1)); new_pos--; } } else { for (unsigned int i = start; i < base; i++) if (info[i].indic_position () == POS_PRE_M) { buffer->merge_clusters (i, hb_min (end, base + 1)); break; } } } /* 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. */ /* Two cases: * * - If repha is encoded as a sequence of characters (Ra,H or Ra,H,ZWJ), then * we should only move it if the sequence ligated to the repha form. * * - If repha is encoded separately and in the logical position, we should only * move it if it did NOT ligate. If it ligated, it's probably the font trying * to make it work without the reordering. */ if (start + 1 < end && info[start].indic_position() == POS_RA_TO_BECOME_REPH && ((info[start].indic_category() == I_Cat(Repha)) ^ _hb_glyph_info_ligated_and_didnt_multiply (&info[start]))) { unsigned int new_reph_pos; reph_position_t reph_pos = indic_plan->config->reph_pos; /* 1. If reph should be positioned after post-base consonant forms, * proceed to step 5. */ if (reph_pos == REPH_POS_AFTER_POST) { goto reph_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. */ { new_reph_pos = start + 1; while (new_reph_pos < base && !is_halant (info[new_reph_pos])) new_reph_pos++; if (new_reph_pos < base && is_halant (info[new_reph_pos])) { /* ->If ZWJ or ZWNJ are following this halant, position is moved after it. */ if (new_reph_pos + 1 < base && is_joiner (info[new_reph_pos + 1])) new_reph_pos++; goto reph_move; } } /* 3. If reph should be repositioned after the main consonant: find the * first consonant not ligated with main, or find the first * consonant that is not a potential pre-base-reordering Ra. */ if (reph_pos == REPH_POS_AFTER_MAIN) { new_reph_pos = base; while (new_reph_pos + 1 < end && info[new_reph_pos + 1].indic_position() <= POS_AFTER_MAIN) new_reph_pos++; if (new_reph_pos < end) goto reph_move; } /* 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. */ /* This is our take on what step 4 is trying to say (and failing, BADLY). */ if (reph_pos == REPH_POS_AFTER_SUB) { new_reph_pos = base; while (new_reph_pos + 1 < end && !( FLAG_UNSAFE (info[new_reph_pos + 1].indic_position()) & (FLAG (POS_POST_C) | FLAG (POS_AFTER_POST) | FLAG (POS_SMVD)))) new_reph_pos++; if (new_reph_pos < end) goto reph_move; } /* 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. */ reph_step_5: { /* Copied from step 2. */ new_reph_pos = start + 1; while (new_reph_pos < base && !is_halant (info[new_reph_pos])) new_reph_pos++; if (new_reph_pos < base && is_halant (info[new_reph_pos])) { /* ->If ZWJ or ZWNJ are following this halant, position is moved after it. */ if (new_reph_pos + 1 < base && is_joiner (info[new_reph_pos + 1])) new_reph_pos++; goto reph_move; } } /* See https://github.com/harfbuzz/harfbuzz/issues/2298#issuecomment-615318654 */ /* 6. Otherwise, reorder reph to the end of the syllable. */ { new_reph_pos = end - 1; while (new_reph_pos > start && info[new_reph_pos].indic_position() == POS_SMVD) new_reph_pos--; /* * If the Reph is to be ending up after a Matra,Halant sequence, * position it before that Halant so it can interact with the Matra. * However, if it's a plain Consonant,Halant we shouldn't do that. * Uniscribe doesn't do this. * TEST: U+0930,U+094D,U+0915,U+094B,U+094D */ if (!indic_plan->uniscribe_bug_compatible && unlikely (is_halant (info[new_reph_pos]))) { for (unsigned int i = base + 1; i < new_reph_pos; i++) if (FLAG_UNSAFE (info[i].indic_category()) & (FLAG (I_Cat(M)) | FLAG (I_Cat(MPst)))) { /* Ok, got it. */ new_reph_pos--; } } goto reph_move; } reph_move: { /* Move */ buffer->merge_clusters (start, new_reph_pos + 1); hb_glyph_info_t reph = info[start]; memmove (&info[start], &info[start + 1], (new_reph_pos - start) * sizeof (info[0])); info[new_reph_pos] = reph; if (start < base && base <= new_reph_pos) base--; } } /* o Reorder pre-base-reordering consonants: * * If a pre-base-reordering consonant is found, reorder it according to * the following rules: */ if (try_pref && base + 1 < end) /* Otherwise there can't be any pre-base-reordering Ra. */ { for (unsigned int i = base + 1; i < end; i++) if ((info[i].mask & indic_plan->mask_array[INDIC_PREF]) != 0) { /* 1. Only reorder a glyph produced by substitution during application * of the <pref> feature. (Note that a font may shape a Ra consonant with * the feature generally but block it in certain contexts.) */ /* Note: We just check that something got substituted. We don't check that * the <pref> feature actually did it... * * Reorder pref only if it ligated. */ if (_hb_glyph_info_ligated_and_didnt_multiply (&info[i])) { /* * 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. */ unsigned int new_pos = base; /* Malayalam / Tamil do not have "half" forms or explicit virama forms. * The glyphs formed by 'half' are Chillus or ligated explicit viramas. * We want to position matra after them. */ if (buffer->props.script != HB_SCRIPT_MALAYALAM && buffer->props.script != HB_SCRIPT_TAMIL) { while (new_pos > start && !(is_one_of (info[new_pos - 1], FLAG (I_Cat(M)) | FLAG (I_Cat(MPst)) | FLAG (I_Cat(H))))) new_pos--; } if (new_pos > start && is_halant (info[new_pos - 1])) { /* -> If ZWJ or ZWNJ follow this halant, position is moved after it. */ if (new_pos < end && is_joiner (info[new_pos])) new_pos++; } { unsigned int old_pos = i; buffer->merge_clusters (new_pos, old_pos + 1); hb_glyph_info_t tmp = info[old_pos]; memmove (&info[new_pos + 1], &info[new_pos], (old_pos - new_pos) * sizeof (info[0])); info[new_pos] = tmp; if (new_pos <= base && base < old_pos) base++; } } break; } } /* Apply 'init' to the Left Matra if it's a word start. */ if (info[start].indic_position () == POS_PRE_M) { if (!start || !(FLAG_UNSAFE (_hb_glyph_info_get_general_category (&info[start - 1])) & FLAG_RANGE (HB_UNICODE_GENERAL_CATEGORY_FORMAT, HB_UNICODE_GENERAL_CATEGORY_NON_SPACING_MARK))) info[start].mask |= indic_plan->mask_array[INDIC_INIT]; else buffer->unsafe_to_break (start - 1, start + 1); } /* * Finish off the clusters and go home! */ if (indic_plan->uniscribe_bug_compatible) { switch ((hb_tag_t) plan->props.script) { case HB_SCRIPT_TAMIL: break; default: /* Uniscribe merges the entire syllable into a single cluster... Except for Tamil. * This means, half forms are submerged into the main consonant's cluster. * This is unnecessary, and makes cursor positioning harder, but that's what * Uniscribe does. */ buffer->merge_clusters (start, end); break; } } } static bool final_reordering_indic (const hb_ot_shape_plan_t *plan, hb_font_t *font HB_UNUSED, hb_buffer_t *buffer) { unsigned int count = buffer->len; if (unlikely (!count)) return false; if (buffer->message (font, "start reordering indic final")) { foreach_syllable (buffer, start, end) final_reordering_syllable_indic (plan, buffer, start, end); (void) buffer->message (font, "end reordering indic final"); } HB_BUFFER_DEALLOCATE_VAR (buffer, indic_category); HB_BUFFER_DEALLOCATE_VAR (buffer, indic_position); return false; } static void preprocess_text_indic (const hb_ot_shape_plan_t *plan, hb_buffer_t *buffer, hb_font_t *font) { const indic_shape_plan_t *indic_plan = (const indic_shape_plan_t *) plan->data; if (!indic_plan->uniscribe_bug_compatible) _hb_preprocess_text_vowel_constraints (plan, buffer, font); } static bool decompose_indic (const hb_ot_shape_normalize_context_t *c, hb_codepoint_t ab, hb_codepoint_t *a, hb_codepoint_t *b) { switch (ab) { /* Don't decompose these. */ case 0x0931u : return false; /* DEVANAGARI LETTER RRA */ // https://github.com/harfbuzz/harfbuzz/issues/779 case 0x09DCu : return false; /* BENGALI LETTER RRA */ case 0x09DDu : return false; /* BENGALI LETTER RHA */ case 0x0B94u : return false; /* TAMIL LETTER AU */ /* * Decompose split matras that don't have Unicode decompositions. */ #if 0 /* Gujarati */ /* This one has no decomposition in Unicode, but needs no decomposition either. */ /* case 0x0AC9u : return false; */ /* Oriya */ case 0x0B57u : *a = no decomp, -> RIGHT; return true; #endif } return (bool) c->unicode->decompose (ab, a, b); } static bool compose_indic (const hb_ot_shape_normalize_context_t *c, hb_codepoint_t a, hb_codepoint_t b, hb_codepoint_t *ab) { /* Avoid recomposing split matras. */ if (HB_UNICODE_GENERAL_CATEGORY_IS_MARK (c->unicode->general_category (a))) return false; /* Composition-exclusion exceptions that we want to recompose. */ if (a == 0x09AFu && b == 0x09BCu) { *ab = 0x09DFu; return true; } return (bool) c->unicode->compose (a, b, ab); } const hb_ot_shaper_t _hb_ot_shaper_indic = { collect_features_indic, override_features_indic, data_create_indic, data_destroy_indic, preprocess_text_indic, nullptr, /* postprocess_glyphs */ decompose_indic, compose_indic, setup_masks_indic, nullptr, /* reorder_marks */ HB_TAG_NONE, /* gpos_tag */ HB_OT_SHAPE_NORMALIZATION_MODE_COMPOSED_DIACRITICS_NO_SHORT_CIRCUIT, HB_OT_SHAPE_ZERO_WIDTH_MARKS_NONE, false, /* fallback_position */ }; #endif