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Diffstat (limited to '')
-rw-r--r-- | gfx/harfbuzz/src/hb-ot-shaper-use.cc | 511 |
1 files changed, 511 insertions, 0 deletions
diff --git a/gfx/harfbuzz/src/hb-ot-shaper-use.cc b/gfx/harfbuzz/src/hb-ot-shaper-use.cc new file mode 100644 index 0000000000..342aba1235 --- /dev/null +++ b/gfx/harfbuzz/src/hb-ot-shaper-use.cc @@ -0,0 +1,511 @@ +/* + * Copyright © 2015 Mozilla Foundation. + * Copyright © 2015 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. + * + * Mozilla Author(s): Jonathan Kew + * Google Author(s): Behdad Esfahbod + */ + +#include "hb.hh" + +#ifndef HB_NO_OT_SHAPE + +#include "hb-ot-shaper-use-machine.hh" +#include "hb-ot-shaper-use-table.hh" +#include "hb-ot-shaper-arabic.hh" +#include "hb-ot-shaper-arabic-joining-list.hh" +#include "hb-ot-shaper-vowel-constraints.hh" + + +/* + * Universal Shaping Engine. + * https://docs.microsoft.com/en-us/typography/script-development/use + */ + +static const hb_tag_t +use_basic_features[] = +{ + /* + * Basic features. + * These features are applied all at once, before reordering, constrained + * to the syllable. + */ + HB_TAG('r','k','r','f'), + HB_TAG('a','b','v','f'), + HB_TAG('b','l','w','f'), + HB_TAG('h','a','l','f'), + HB_TAG('p','s','t','f'), + HB_TAG('v','a','t','u'), + HB_TAG('c','j','c','t'), +}; +static const hb_tag_t +use_topographical_features[] = +{ + HB_TAG('i','s','o','l'), + HB_TAG('i','n','i','t'), + HB_TAG('m','e','d','i'), + HB_TAG('f','i','n','a'), +}; +/* Same order as use_topographical_features. */ +enum joining_form_t { + JOINING_FORM_ISOL, + JOINING_FORM_INIT, + JOINING_FORM_MEDI, + JOINING_FORM_FINA, + _JOINING_FORM_NONE +}; +static const hb_tag_t +use_other_features[] = +{ + /* + * Other features. + * These features are applied all at once, after reordering and + * clearing syllables. + */ + HB_TAG('a','b','v','s'), + HB_TAG('b','l','w','s'), + HB_TAG('h','a','l','n'), + HB_TAG('p','r','e','s'), + HB_TAG('p','s','t','s'), +}; + +static bool +setup_syllables_use (const hb_ot_shape_plan_t *plan, + hb_font_t *font, + hb_buffer_t *buffer); +static bool +record_rphf_use (const hb_ot_shape_plan_t *plan, + hb_font_t *font, + hb_buffer_t *buffer); +static bool +record_pref_use (const hb_ot_shape_plan_t *plan, + hb_font_t *font, + hb_buffer_t *buffer); +static bool +reorder_use (const hb_ot_shape_plan_t *plan, + hb_font_t *font, + hb_buffer_t *buffer); + +static void +collect_features_use (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_use); + + /* "Default glyph pre-processing group" */ + map->enable_feature (HB_TAG('l','o','c','l'), F_PER_SYLLABLE); + map->enable_feature (HB_TAG('c','c','m','p'), F_PER_SYLLABLE); + map->enable_feature (HB_TAG('n','u','k','t'), F_PER_SYLLABLE); + map->enable_feature (HB_TAG('a','k','h','n'), F_MANUAL_ZWJ | F_PER_SYLLABLE); + + /* "Reordering group" */ + map->add_gsub_pause (_hb_clear_substitution_flags); + map->add_feature (HB_TAG('r','p','h','f'), F_MANUAL_ZWJ | F_PER_SYLLABLE); + map->add_gsub_pause (record_rphf_use); + map->add_gsub_pause (_hb_clear_substitution_flags); + map->enable_feature (HB_TAG('p','r','e','f'), F_MANUAL_ZWJ | F_PER_SYLLABLE); + map->add_gsub_pause (record_pref_use); + + /* "Orthographic unit shaping group" */ + for (unsigned int i = 0; i < ARRAY_LENGTH (use_basic_features); i++) + map->enable_feature (use_basic_features[i], F_MANUAL_ZWJ | F_PER_SYLLABLE); + + map->add_gsub_pause (reorder_use); + map->add_gsub_pause (hb_syllabic_clear_var); // Don't need syllables anymore, use stop to free buffer var + + /* "Topographical features" */ + for (unsigned int i = 0; i < ARRAY_LENGTH (use_topographical_features); i++) + map->add_feature (use_topographical_features[i]); + map->add_gsub_pause (nullptr); + + /* "Standard typographic presentation" */ + for (unsigned int i = 0; i < ARRAY_LENGTH (use_other_features); i++) + map->enable_feature (use_other_features[i], F_MANUAL_ZWJ); +} + +struct use_shape_plan_t +{ + hb_mask_t rphf_mask; + + arabic_shape_plan_t *arabic_plan; +}; + +static void * +data_create_use (const hb_ot_shape_plan_t *plan) +{ + use_shape_plan_t *use_plan = (use_shape_plan_t *) hb_calloc (1, sizeof (use_shape_plan_t)); + if (unlikely (!use_plan)) + return nullptr; + + use_plan->rphf_mask = plan->map.get_1_mask (HB_TAG('r','p','h','f')); + + if (has_arabic_joining (plan->props.script)) + { + use_plan->arabic_plan = (arabic_shape_plan_t *) data_create_arabic (plan); + if (unlikely (!use_plan->arabic_plan)) + { + hb_free (use_plan); + return nullptr; + } + } + + return use_plan; +} + +static void +data_destroy_use (void *data) +{ + use_shape_plan_t *use_plan = (use_shape_plan_t *) data; + + if (use_plan->arabic_plan) + data_destroy_arabic (use_plan->arabic_plan); + + hb_free (data); +} + +static void +setup_masks_use (const hb_ot_shape_plan_t *plan, + hb_buffer_t *buffer, + hb_font_t *font HB_UNUSED) +{ + const use_shape_plan_t *use_plan = (const use_shape_plan_t *) plan->data; + + /* Do this before allocating use_category(). */ + if (use_plan->arabic_plan) + { + setup_masks_arabic_plan (use_plan->arabic_plan, buffer, plan->props.script); + } + + HB_BUFFER_ALLOCATE_VAR (buffer, use_category); + + /* 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++) + info[i].use_category() = hb_use_get_category (info[i].codepoint); +} + +static void +setup_rphf_mask (const hb_ot_shape_plan_t *plan, + hb_buffer_t *buffer) +{ + const use_shape_plan_t *use_plan = (const use_shape_plan_t *) plan->data; + + hb_mask_t mask = use_plan->rphf_mask; + if (!mask) return; + + hb_glyph_info_t *info = buffer->info; + + foreach_syllable (buffer, start, end) + { + unsigned int limit = info[start].use_category() == USE(R) ? 1 : hb_min (3u, end - start); + for (unsigned int i = start; i < start + limit; i++) + info[i].mask |= mask; + } +} + +static void +setup_topographical_masks (const hb_ot_shape_plan_t *plan, + hb_buffer_t *buffer) +{ + const use_shape_plan_t *use_plan = (const use_shape_plan_t *) plan->data; + if (use_plan->arabic_plan) + return; + + static_assert ((JOINING_FORM_INIT < 4 && JOINING_FORM_ISOL < 4 && JOINING_FORM_MEDI < 4 && JOINING_FORM_FINA < 4), ""); + hb_mask_t masks[4], all_masks = 0; + for (unsigned int i = 0; i < 4; i++) + { + masks[i] = plan->map.get_1_mask (use_topographical_features[i]); + if (masks[i] == plan->map.get_global_mask ()) + masks[i] = 0; + all_masks |= masks[i]; + } + if (!all_masks) + return; + hb_mask_t other_masks = ~all_masks; + + unsigned int last_start = 0; + joining_form_t last_form = _JOINING_FORM_NONE; + hb_glyph_info_t *info = buffer->info; + foreach_syllable (buffer, start, end) + { + use_syllable_type_t syllable_type = (use_syllable_type_t) (info[start].syllable() & 0x0F); + switch (syllable_type) + { + case use_hieroglyph_cluster: + case use_non_cluster: + /* These don't join. Nothing to do. */ + last_form = _JOINING_FORM_NONE; + break; + + case use_virama_terminated_cluster: + case use_sakot_terminated_cluster: + case use_standard_cluster: + case use_number_joiner_terminated_cluster: + case use_numeral_cluster: + case use_symbol_cluster: + case use_broken_cluster: + + bool join = last_form == JOINING_FORM_FINA || last_form == JOINING_FORM_ISOL; + + if (join) + { + /* Fixup previous syllable's form. */ + last_form = last_form == JOINING_FORM_FINA ? JOINING_FORM_MEDI : JOINING_FORM_INIT; + for (unsigned int i = last_start; i < start; i++) + info[i].mask = (info[i].mask & other_masks) | masks[last_form]; + } + + /* Form for this syllable. */ + last_form = join ? JOINING_FORM_FINA : JOINING_FORM_ISOL; + for (unsigned int i = start; i < end; i++) + info[i].mask = (info[i].mask & other_masks) | masks[last_form]; + + break; + } + + last_start = start; + } +} + +static bool +setup_syllables_use (const hb_ot_shape_plan_t *plan, + hb_font_t *font HB_UNUSED, + hb_buffer_t *buffer) +{ + HB_BUFFER_ALLOCATE_VAR (buffer, syllable); + find_syllables_use (buffer); + foreach_syllable (buffer, start, end) + buffer->unsafe_to_break (start, end); + setup_rphf_mask (plan, buffer); + setup_topographical_masks (plan, buffer); + return false; +} + +static bool +record_rphf_use (const hb_ot_shape_plan_t *plan, + hb_font_t *font HB_UNUSED, + hb_buffer_t *buffer) +{ + const use_shape_plan_t *use_plan = (const use_shape_plan_t *) plan->data; + + hb_mask_t mask = use_plan->rphf_mask; + if (!mask) return false; + hb_glyph_info_t *info = buffer->info; + + foreach_syllable (buffer, start, end) + { + /* Mark a substituted repha as USE(R). */ + for (unsigned int i = start; i < end && (info[i].mask & mask); i++) + if (_hb_glyph_info_substituted (&info[i])) + { + info[i].use_category() = USE(R); + break; + } + } + return false; +} + +static bool +record_pref_use (const hb_ot_shape_plan_t *plan HB_UNUSED, + hb_font_t *font HB_UNUSED, + hb_buffer_t *buffer) +{ + hb_glyph_info_t *info = buffer->info; + + foreach_syllable (buffer, start, end) + { + /* Mark a substituted pref as VPre, as they behave the same way. */ + for (unsigned int i = start; i < end; i++) + if (_hb_glyph_info_substituted (&info[i])) + { + info[i].use_category() = USE(VPre); + break; + } + } + return false; +} + +static inline bool +is_halant_use (const hb_glyph_info_t &info) +{ + return (info.use_category() == USE(H) || info.use_category() == USE(HVM) || info.use_category() == USE(IS)) && + !_hb_glyph_info_ligated (&info); +} + +static void +reorder_syllable_use (hb_buffer_t *buffer, unsigned int start, unsigned int end) +{ + use_syllable_type_t syllable_type = (use_syllable_type_t) (buffer->info[start].syllable() & 0x0F); + /* Only a few syllable types need reordering. */ + if (unlikely (!(FLAG_UNSAFE (syllable_type) & + (FLAG (use_virama_terminated_cluster) | + FLAG (use_sakot_terminated_cluster) | + FLAG (use_standard_cluster) | + FLAG (use_symbol_cluster) | + FLAG (use_broken_cluster) | + 0)))) + return; + + hb_glyph_info_t *info = buffer->info; + +#define POST_BASE_FLAGS64 (FLAG64 (USE(FAbv)) | \ + FLAG64 (USE(FBlw)) | \ + FLAG64 (USE(FPst)) | \ + FLAG64 (USE(MAbv)) | \ + FLAG64 (USE(MBlw)) | \ + FLAG64 (USE(MPst)) | \ + FLAG64 (USE(MPre)) | \ + FLAG64 (USE(VAbv)) | \ + FLAG64 (USE(VBlw)) | \ + FLAG64 (USE(VPst)) | \ + FLAG64 (USE(VPre)) | \ + FLAG64 (USE(VMAbv)) | \ + FLAG64 (USE(VMBlw)) | \ + FLAG64 (USE(VMPst)) | \ + FLAG64 (USE(VMPre))) + + /* Move things forward. */ + if (info[start].use_category() == USE(R) && end - start > 1) + { + /* Got a repha. Reorder it towards the end, but before the first post-base + * glyph. */ + for (unsigned int i = start + 1; i < end; i++) + { + bool is_post_base_glyph = (FLAG64_UNSAFE (info[i].use_category()) & POST_BASE_FLAGS64) || + is_halant_use (info[i]); + if (is_post_base_glyph || i == end - 1) + { + /* If we hit a post-base glyph, move before it; otherwise move to the + * end. Shift things in between backward. */ + + if (is_post_base_glyph) + i--; + + buffer->merge_clusters (start, i + 1); + hb_glyph_info_t t = info[start]; + memmove (&info[start], &info[start + 1], (i - start) * sizeof (info[0])); + info[i] = t; + + break; + } + } + } + + /* Move things back. */ + unsigned int j = start; + for (unsigned int i = start; i < end; i++) + { + uint32_t flag = FLAG_UNSAFE (info[i].use_category()); + if (is_halant_use (info[i])) + { + /* If we hit a halant, move after it; otherwise move to the beginning, and + * shift things in between forward. */ + j = i + 1; + } + else if (((flag) & (FLAG (USE(VPre)) | FLAG (USE(VMPre)))) && + /* Only move the first component of a MultipleSubst. */ + 0 == _hb_glyph_info_get_lig_comp (&info[i]) && + j < i) + { + buffer->merge_clusters (j, i + 1); + hb_glyph_info_t t = info[i]; + memmove (&info[j + 1], &info[j], (i - j) * sizeof (info[0])); + info[j] = t; + } + } +} + +static bool +reorder_use (const hb_ot_shape_plan_t *plan, + hb_font_t *font, + hb_buffer_t *buffer) +{ + bool ret = false; + if (buffer->message (font, "start reordering USE")) + { + if (hb_syllabic_insert_dotted_circles (font, buffer, + use_broken_cluster, + USE(B), + USE(R))) + ret = true; + + foreach_syllable (buffer, start, end) + reorder_syllable_use (buffer, start, end); + + (void) buffer->message (font, "end reordering USE"); + } + + HB_BUFFER_DEALLOCATE_VAR (buffer, use_category); + + return ret; +} + + +static void +preprocess_text_use (const hb_ot_shape_plan_t *plan, + hb_buffer_t *buffer, + hb_font_t *font) +{ + _hb_preprocess_text_vowel_constraints (plan, buffer, font); +} + +static bool +compose_use (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; + + return (bool)c->unicode->compose (a, b, ab); +} + + +const hb_ot_shaper_t _hb_ot_shaper_use = +{ + collect_features_use, + nullptr, /* override_features */ + data_create_use, + data_destroy_use, + preprocess_text_use, + nullptr, /* postprocess_glyphs */ + nullptr, /* decompose */ + compose_use, + setup_masks_use, + nullptr, /* reorder_marks */ + HB_TAG_NONE, /* gpos_tag */ + HB_OT_SHAPE_NORMALIZATION_MODE_COMPOSED_DIACRITICS_NO_SHORT_CIRCUIT, + HB_OT_SHAPE_ZERO_WIDTH_MARKS_BY_GDEF_EARLY, + false, /* fallback_position */ +}; + + +#endif |