/* * Copyright © 2010,2012 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-ot-shape-complex-arabic-private.hh" #include "hb-ot-shape-private.hh" #ifndef HB_DEBUG_ARABIC #define HB_DEBUG_ARABIC (HB_DEBUG+0) #endif /* buffer var allocations */ #define arabic_shaping_action() complex_var_u8_0() /* arabic shaping action */ #define HB_BUFFER_SCRATCH_FLAG_ARABIC_HAS_STCH HB_BUFFER_SCRATCH_FLAG_COMPLEX0 /* See: * https://github.com/behdad/harfbuzz/commit/6e6f82b6f3dde0fc6c3c7d991d9ec6cfff57823d#commitcomment-14248516 */ #define HB_ARABIC_GENERAL_CATEGORY_IS_WORD(gen_cat) \ (FLAG_SAFE (gen_cat) & \ (FLAG (HB_UNICODE_GENERAL_CATEGORY_UNASSIGNED) | \ FLAG (HB_UNICODE_GENERAL_CATEGORY_PRIVATE_USE) | \ /*FLAG (HB_UNICODE_GENERAL_CATEGORY_LOWERCASE_LETTER) |*/ \ FLAG (HB_UNICODE_GENERAL_CATEGORY_MODIFIER_LETTER) | \ FLAG (HB_UNICODE_GENERAL_CATEGORY_OTHER_LETTER) | \ /*FLAG (HB_UNICODE_GENERAL_CATEGORY_TITLECASE_LETTER) |*/ \ /*FLAG (HB_UNICODE_GENERAL_CATEGORY_UPPERCASE_LETTER) |*/ \ FLAG (HB_UNICODE_GENERAL_CATEGORY_SPACING_MARK) | \ FLAG (HB_UNICODE_GENERAL_CATEGORY_ENCLOSING_MARK) | \ FLAG (HB_UNICODE_GENERAL_CATEGORY_NON_SPACING_MARK) | \ FLAG (HB_UNICODE_GENERAL_CATEGORY_DECIMAL_NUMBER) | \ FLAG (HB_UNICODE_GENERAL_CATEGORY_LETTER_NUMBER) | \ FLAG (HB_UNICODE_GENERAL_CATEGORY_OTHER_NUMBER) | \ FLAG (HB_UNICODE_GENERAL_CATEGORY_CURRENCY_SYMBOL) | \ FLAG (HB_UNICODE_GENERAL_CATEGORY_MODIFIER_SYMBOL) | \ FLAG (HB_UNICODE_GENERAL_CATEGORY_MATH_SYMBOL) | \ FLAG (HB_UNICODE_GENERAL_CATEGORY_OTHER_SYMBOL))) /* * Joining types: */ /* * Bits used in the joining tables */ enum hb_arabic_joining_type_t { JOINING_TYPE_U = 0, JOINING_TYPE_L = 1, JOINING_TYPE_R = 2, JOINING_TYPE_D = 3, JOINING_TYPE_C = JOINING_TYPE_D, JOINING_GROUP_ALAPH = 4, JOINING_GROUP_DALATH_RISH = 5, NUM_STATE_MACHINE_COLS = 6, JOINING_TYPE_T = 7, JOINING_TYPE_X = 8 /* means: use general-category to choose between U or T. */ }; #include "hb-ot-shape-complex-arabic-table.hh" static unsigned int get_joining_type (hb_codepoint_t u, hb_unicode_general_category_t gen_cat) { unsigned int j_type = joining_type(u); if (likely (j_type != JOINING_TYPE_X)) return j_type; return (FLAG_SAFE(gen_cat) & (FLAG(HB_UNICODE_GENERAL_CATEGORY_NON_SPACING_MARK) | FLAG(HB_UNICODE_GENERAL_CATEGORY_ENCLOSING_MARK) | FLAG(HB_UNICODE_GENERAL_CATEGORY_FORMAT)) ) ? JOINING_TYPE_T : JOINING_TYPE_U; } #define FEATURE_IS_SYRIAC(tag) hb_in_range ((unsigned char) (tag), '2', '3') static const hb_tag_t arabic_features[] = { HB_TAG('i','s','o','l'), HB_TAG('f','i','n','a'), HB_TAG('f','i','n','2'), HB_TAG('f','i','n','3'), HB_TAG('m','e','d','i'), HB_TAG('m','e','d','2'), HB_TAG('i','n','i','t'), HB_TAG_NONE }; /* Same order as the feature array */ enum arabic_action_t { ISOL, FINA, FIN2, FIN3, MEDI, MED2, INIT, NONE, ARABIC_NUM_FEATURES = NONE, /* We abuse the same byte for other things... */ STCH_FIXED, STCH_REPEATING, }; static const struct arabic_state_table_entry { uint8_t prev_action; uint8_t curr_action; uint16_t next_state; } arabic_state_table[][NUM_STATE_MACHINE_COLS] = { /* jt_U, jt_L, jt_R, jt_D, jg_ALAPH, jg_DALATH_RISH */ /* State 0: prev was U, not willing to join. */ { {NONE,NONE,0}, {NONE,ISOL,2}, {NONE,ISOL,1}, {NONE,ISOL,2}, {NONE,ISOL,1}, {NONE,ISOL,6}, }, /* State 1: prev was R or ISOL/ALAPH, not willing to join. */ { {NONE,NONE,0}, {NONE,ISOL,2}, {NONE,ISOL,1}, {NONE,ISOL,2}, {NONE,FIN2,5}, {NONE,ISOL,6}, }, /* State 2: prev was D/L in ISOL form, willing to join. */ { {NONE,NONE,0}, {NONE,ISOL,2}, {INIT,FINA,1}, {INIT,FINA,3}, {INIT,FINA,4}, {INIT,FINA,6}, }, /* State 3: prev was D in FINA form, willing to join. */ { {NONE,NONE,0}, {NONE,ISOL,2}, {MEDI,FINA,1}, {MEDI,FINA,3}, {MEDI,FINA,4}, {MEDI,FINA,6}, }, /* State 4: prev was FINA ALAPH, not willing to join. */ { {NONE,NONE,0}, {NONE,ISOL,2}, {MED2,ISOL,1}, {MED2,ISOL,2}, {MED2,FIN2,5}, {MED2,ISOL,6}, }, /* State 5: prev was FIN2/FIN3 ALAPH, not willing to join. */ { {NONE,NONE,0}, {NONE,ISOL,2}, {ISOL,ISOL,1}, {ISOL,ISOL,2}, {ISOL,FIN2,5}, {ISOL,ISOL,6}, }, /* State 6: prev was DALATH/RISH, not willing to join. */ { {NONE,NONE,0}, {NONE,ISOL,2}, {NONE,ISOL,1}, {NONE,ISOL,2}, {NONE,FIN3,5}, {NONE,ISOL,6}, } }; static void nuke_joiners (const hb_ot_shape_plan_t *plan, hb_font_t *font, hb_buffer_t *buffer); static void arabic_fallback_shape (const hb_ot_shape_plan_t *plan, hb_font_t *font, hb_buffer_t *buffer); static void record_stch (const hb_ot_shape_plan_t *plan, hb_font_t *font, hb_buffer_t *buffer); static void collect_features_arabic (hb_ot_shape_planner_t *plan) { hb_ot_map_builder_t *map = &plan->map; /* We apply features according to the Arabic spec, with pauses * in between most. * * The pause between init/medi/... and rlig is required. See eg: * https://bugzilla.mozilla.org/show_bug.cgi?id=644184 * * The pauses between init/medi/... themselves are not necessarily * needed as only one of those features is applied to any character. * The only difference it makes is when fonts have contextual * substitutions. We now follow the order of the spec, which makes * for better experience if that's what Uniscribe is doing. * * At least for Arabic, looks like Uniscribe has a pause between * rlig and calt. Otherwise the IranNastaliq's ALLAH ligature won't * work. However, testing shows that rlig and calt are applied * together for Mongolian in Uniscribe. As such, we only add a * pause for Arabic, not other scripts. * * A pause after calt is required to make KFGQPC Uthmanic Script HAFS * work correctly. See https://github.com/behdad/harfbuzz/issues/505 */ map->add_gsub_pause (nuke_joiners); map->add_global_bool_feature (HB_TAG('s','t','c','h')); map->add_gsub_pause (record_stch); map->add_global_bool_feature (HB_TAG('c','c','m','p')); map->add_global_bool_feature (HB_TAG('l','o','c','l')); map->add_gsub_pause (NULL); for (unsigned int i = 0; i < ARABIC_NUM_FEATURES; i++) { bool has_fallback = plan->props.script == HB_SCRIPT_ARABIC && !FEATURE_IS_SYRIAC (arabic_features[i]); map->add_feature (arabic_features[i], 1, has_fallback ? F_HAS_FALLBACK : F_NONE); map->add_gsub_pause (NULL); } map->add_feature (HB_TAG('r','l','i','g'), 1, F_GLOBAL|F_HAS_FALLBACK); if (plan->props.script == HB_SCRIPT_ARABIC) map->add_gsub_pause (arabic_fallback_shape); /* No pause after rclt. See 98460779bae19e4d64d29461ff154b3527bf8420. */ map->add_global_bool_feature (HB_TAG('r','c','l','t')); map->add_global_bool_feature (HB_TAG('c','a','l','t')); map->add_gsub_pause (NULL); /* The spec includes 'cswh'. Earlier versions of Windows * used to enable this by default, but testing suggests * that Windows 8 and later do not enable it by default, * and spec now says 'Off by default'. * We disabled this in ae23c24c32. * Note that IranNastaliq uses this feature extensively * to fixup broken glyph sequences. Oh well... * Test case: U+0643,U+0640,U+0631. */ //map->add_global_bool_feature (HB_TAG('c','s','w','h')); map->add_global_bool_feature (HB_TAG('m','s','e','t')); } #include "hb-ot-shape-complex-arabic-fallback.hh" struct arabic_shape_plan_t { ASSERT_POD (); /* The "+ 1" in the next array is to accommodate for the "NONE" command, * which is not an OpenType feature, but this simplifies the code by not * having to do a "if (... < NONE) ..." and just rely on the fact that * mask_array[NONE] == 0. */ hb_mask_t mask_array[ARABIC_NUM_FEATURES + 1]; arabic_fallback_plan_t *fallback_plan; unsigned int do_fallback : 1; unsigned int has_stch : 1; }; void * data_create_arabic (const hb_ot_shape_plan_t *plan) { arabic_shape_plan_t *arabic_plan = (arabic_shape_plan_t *) calloc (1, sizeof (arabic_shape_plan_t)); if (unlikely (!arabic_plan)) return NULL; arabic_plan->do_fallback = plan->props.script == HB_SCRIPT_ARABIC; arabic_plan->has_stch = !!plan->map.get_1_mask (HB_TAG ('s','t','c','h')); for (unsigned int i = 0; i < ARABIC_NUM_FEATURES; i++) { arabic_plan->mask_array[i] = plan->map.get_1_mask (arabic_features[i]); arabic_plan->do_fallback = arabic_plan->do_fallback && (FEATURE_IS_SYRIAC (arabic_features[i]) || plan->map.needs_fallback (arabic_features[i])); } return arabic_plan; } void data_destroy_arabic (void *data) { arabic_shape_plan_t *arabic_plan = (arabic_shape_plan_t *) data; arabic_fallback_plan_destroy (arabic_plan->fallback_plan); free (data); } static void arabic_joining (hb_buffer_t *buffer) { unsigned int count = buffer->len; hb_glyph_info_t *info = buffer->info; unsigned int prev = (unsigned int) -1, state = 0; /* Check pre-context */ for (unsigned int i = 0; i < buffer->context_len[0]; i++) { unsigned int this_type = get_joining_type (buffer->context[0][i], buffer->unicode->general_category (buffer->context[0][i])); if (unlikely (this_type == JOINING_TYPE_T)) continue; const arabic_state_table_entry *entry = &arabic_state_table[state][this_type]; state = entry->next_state; break; } for (unsigned int i = 0; i < count; i++) { unsigned int this_type = get_joining_type (info[i].codepoint, _hb_glyph_info_get_general_category (&info[i])); if (unlikely (this_type == JOINING_TYPE_T)) { info[i].arabic_shaping_action() = NONE; continue; } const arabic_state_table_entry *entry = &arabic_state_table[state][this_type]; if (entry->prev_action != NONE && prev != (unsigned int) -1) info[prev].arabic_shaping_action() = entry->prev_action; info[i].arabic_shaping_action() = entry->curr_action; prev = i; state = entry->next_state; } for (unsigned int i = 0; i < buffer->context_len[1]; i++) { unsigned int this_type = get_joining_type (buffer->context[1][i], buffer->unicode->general_category (buffer->context[1][i])); if (unlikely (this_type == JOINING_TYPE_T)) continue; const arabic_state_table_entry *entry = &arabic_state_table[state][this_type]; if (entry->prev_action != NONE && prev != (unsigned int) -1) info[prev].arabic_shaping_action() = entry->prev_action; break; } } static void mongolian_variation_selectors (hb_buffer_t *buffer) { /* Copy arabic_shaping_action() from base to Mongolian variation selectors. */ unsigned int count = buffer->len; hb_glyph_info_t *info = buffer->info; for (unsigned int i = 1; i < count; i++) if (unlikely (hb_in_range (info[i].codepoint, 0x180Bu, 0x180Du))) info[i].arabic_shaping_action() = info[i - 1].arabic_shaping_action(); } void setup_masks_arabic_plan (const arabic_shape_plan_t *arabic_plan, hb_buffer_t *buffer, hb_script_t script) { HB_BUFFER_ALLOCATE_VAR (buffer, arabic_shaping_action); arabic_joining (buffer); if (script == HB_SCRIPT_MONGOLIAN) mongolian_variation_selectors (buffer); unsigned int count = buffer->len; hb_glyph_info_t *info = buffer->info; for (unsigned int i = 0; i < count; i++) info[i].mask |= arabic_plan->mask_array[info[i].arabic_shaping_action()]; } static void setup_masks_arabic (const hb_ot_shape_plan_t *plan, hb_buffer_t *buffer, hb_font_t *font HB_UNUSED) { const arabic_shape_plan_t *arabic_plan = (const arabic_shape_plan_t *) plan->data; setup_masks_arabic_plan (arabic_plan, buffer, plan->props.script); } static void nuke_joiners (const hb_ot_shape_plan_t *plan HB_UNUSED, hb_font_t *font HB_UNUSED, hb_buffer_t *buffer) { unsigned int count = buffer->len; hb_glyph_info_t *info = buffer->info; for (unsigned int i = 0; i < count; i++) if (_hb_glyph_info_is_zwj (&info[i])) _hb_glyph_info_flip_joiners (&info[i]); } static void arabic_fallback_shape (const hb_ot_shape_plan_t *plan, hb_font_t *font, hb_buffer_t *buffer) { const arabic_shape_plan_t *arabic_plan = (const arabic_shape_plan_t *) plan->data; if (!arabic_plan->do_fallback) return; retry: arabic_fallback_plan_t *fallback_plan = (arabic_fallback_plan_t *) hb_atomic_ptr_get (&arabic_plan->fallback_plan); if (unlikely (!fallback_plan)) { /* This sucks. We need a font to build the fallback plan... */ fallback_plan = arabic_fallback_plan_create (plan, font); if (unlikely (!hb_atomic_ptr_cmpexch (&(const_cast (arabic_plan))->fallback_plan, NULL, fallback_plan))) { arabic_fallback_plan_destroy (fallback_plan); goto retry; } } arabic_fallback_plan_shape (fallback_plan, font, buffer); } /* * Stretch feature: "stch". * See example here: * https://www.microsoft.com/typography/OpenTypeDev/syriac/intro.htm * We implement this in a generic way, such that the Arabic subtending * marks can use it as well. */ static void record_stch (const hb_ot_shape_plan_t *plan, hb_font_t *font, hb_buffer_t *buffer) { const arabic_shape_plan_t *arabic_plan = (const arabic_shape_plan_t *) plan->data; if (!arabic_plan->has_stch) return; /* 'stch' feature was just applied. Look for anything that multiplied, * and record it for stch treatment later. Note that rtlm, frac, etc * are applied before stch, but we assume that they didn't result in * anything multiplying into 5 pieces, so it's safe-ish... */ unsigned int count = buffer->len; hb_glyph_info_t *info = buffer->info; for (unsigned int i = 0; i < count; i++) if (unlikely (_hb_glyph_info_multiplied (&info[i]))) { unsigned int comp = _hb_glyph_info_get_lig_comp (&info[i]); info[i].arabic_shaping_action() = comp % 2 ? STCH_REPEATING : STCH_FIXED; buffer->scratch_flags |= HB_BUFFER_SCRATCH_FLAG_ARABIC_HAS_STCH; } } static void apply_stch (const hb_ot_shape_plan_t *plan, hb_buffer_t *buffer, hb_font_t *font) { if (likely (!(buffer->scratch_flags & HB_BUFFER_SCRATCH_FLAG_ARABIC_HAS_STCH))) return; /* The Arabic shaper currently always processes in RTL mode, so we should * stretch / position the stretched pieces to the left / preceding glyphs. */ /* We do a two pass implementation: * First pass calculates the exact number of extra glyphs we need, * We then enlarge buffer to have that much room, * Second pass applies the stretch, copying things to the end of buffer. */ int sign = font->x_scale < 0 ? -1 : +1; unsigned int extra_glyphs_needed = 0; // Set during MEASURE, used during CUT typedef enum { MEASURE, CUT } step_t; for (step_t step = MEASURE; step <= CUT; step = (step_t) (step + 1)) { unsigned int count = buffer->len; hb_glyph_info_t *info = buffer->info; hb_glyph_position_t *pos = buffer->pos; unsigned int new_len = count + extra_glyphs_needed; // write head during CUT unsigned int j = new_len; for (unsigned int i = count; i; i--) { if (!hb_in_range (info[i - 1].arabic_shaping_action(), STCH_FIXED, STCH_REPEATING)) { if (step == CUT) { --j; info[j] = info[i - 1]; pos[j] = pos[i - 1]; } continue; } /* Yay, justification! */ hb_position_t w_total = 0; // Total to be filled hb_position_t w_fixed = 0; // Sum of fixed tiles hb_position_t w_repeating = 0; // Sum of repeating tiles int n_fixed = 0; int n_repeating = 0; unsigned int end = i; while (i && hb_in_range (info[i - 1].arabic_shaping_action(), STCH_FIXED, STCH_REPEATING)) { i--; hb_position_t width = font->get_glyph_h_advance (info[i].codepoint); if (info[i].arabic_shaping_action() == STCH_FIXED) { w_fixed += width; n_fixed++; } else { w_repeating += width; n_repeating++; } } unsigned int start = i; unsigned int context = i; while (context && !hb_in_range (info[context - 1].arabic_shaping_action(), STCH_FIXED, STCH_REPEATING) && (_hb_glyph_info_is_default_ignorable (&info[context - 1]) || HB_ARABIC_GENERAL_CATEGORY_IS_WORD (_hb_glyph_info_get_general_category (&info[context - 1])))) { context--; w_total += pos[context].x_advance; } i++; // Don't touch i again. DEBUG_MSG (ARABIC, NULL, "%s stretch at (%d,%d,%d)", step == MEASURE ? "measuring" : "cutting", context, start, end); DEBUG_MSG (ARABIC, NULL, "rest of word: count=%d width %d", start - context, w_total); DEBUG_MSG (ARABIC, NULL, "fixed tiles: count=%d width=%d", n_fixed, w_fixed); DEBUG_MSG (ARABIC, NULL, "repeating tiles: count=%d width=%d", n_repeating, w_repeating); /* Number of additional times to repeat each repeating tile. */ int n_copies = 0; hb_position_t w_remaining = w_total - w_fixed; if (sign * w_remaining > sign * w_repeating && sign * w_repeating > 0) n_copies = (sign * w_remaining) / (sign * w_repeating) - 1; /* See if we can improve the fit by adding an extra repeat and squeezing them together a bit. */ hb_position_t extra_repeat_overlap = 0; hb_position_t shortfall = sign * w_remaining - sign * w_repeating * (n_copies + 1); if (shortfall > 0 && n_repeating > 0) { ++n_copies; hb_position_t excess = (n_copies + 1) * sign * w_repeating - sign * w_remaining; if (excess > 0) extra_repeat_overlap = excess / (n_copies * n_repeating); } if (step == MEASURE) { extra_glyphs_needed += n_copies * n_repeating; DEBUG_MSG (ARABIC, NULL, "will add extra %d copies of repeating tiles", n_copies); } else { hb_position_t x_offset = 0; for (unsigned int k = end; k > start; k--) { hb_position_t width = font->get_glyph_h_advance (info[k - 1].codepoint); unsigned int repeat = 1; if (info[k - 1].arabic_shaping_action() == STCH_REPEATING) repeat += n_copies; DEBUG_MSG (ARABIC, NULL, "appending %d copies of glyph %d; j=%d", repeat, info[k - 1].codepoint, j); for (unsigned int n = 0; n < repeat; n++) { x_offset -= width; if (n > 0) x_offset += extra_repeat_overlap; pos[k - 1].x_offset = x_offset; /* Append copy. */ --j; info[j] = info[k - 1]; pos[j] = pos[k - 1]; } } } } if (step == MEASURE) { if (unlikely (!buffer->ensure (count + extra_glyphs_needed))) break; } else { assert (j == 0); buffer->len = new_len; } } } static void postprocess_glyphs_arabic (const hb_ot_shape_plan_t *plan, hb_buffer_t *buffer, hb_font_t *font) { apply_stch (plan, buffer, font); HB_BUFFER_DEALLOCATE_VAR (buffer, arabic_shaping_action); } const hb_ot_complex_shaper_t _hb_ot_complex_shaper_arabic = { "arabic", collect_features_arabic, NULL, /* override_features */ data_create_arabic, data_destroy_arabic, NULL, /* preprocess_text */ postprocess_glyphs_arabic, HB_OT_SHAPE_NORMALIZATION_MODE_DEFAULT, NULL, /* decompose */ NULL, /* compose */ setup_masks_arabic, NULL, /* disable_otl */ HB_OT_SHAPE_ZERO_WIDTH_MARKS_BY_GDEF_LATE, true, /* fallback_position */ };