| /* |
| * 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.hh" |
| |
| #ifndef HB_NO_OT_SHAPE |
| |
| #include "hb-ot-shaper.hh" |
| |
| |
| /* Thai / Lao shaper */ |
| |
| |
| /* PUA shaping */ |
| |
| |
| enum thai_consonant_type_t |
| { |
| NC, |
| AC, |
| RC, |
| DC, |
| NOT_CONSONANT, |
| NUM_CONSONANT_TYPES = NOT_CONSONANT |
| }; |
| |
| static thai_consonant_type_t |
| get_consonant_type (hb_codepoint_t u) |
| { |
| if (u == 0x0E1Bu || u == 0x0E1Du || u == 0x0E1Fu/* || u == 0x0E2Cu*/) |
| return AC; |
| if (u == 0x0E0Du || u == 0x0E10u) |
| return RC; |
| if (u == 0x0E0Eu || u == 0x0E0Fu) |
| return DC; |
| if (hb_in_range<hb_codepoint_t> (u, 0x0E01u, 0x0E2Eu)) |
| return NC; |
| return NOT_CONSONANT; |
| } |
| |
| |
| enum thai_mark_type_t |
| { |
| AV, |
| BV, |
| T, |
| NOT_MARK, |
| NUM_MARK_TYPES = NOT_MARK |
| }; |
| |
| static thai_mark_type_t |
| get_mark_type (hb_codepoint_t u) |
| { |
| if (u == 0x0E31u || hb_in_range<hb_codepoint_t> (u, 0x0E34u, 0x0E37u) || |
| u == 0x0E47u || hb_in_range<hb_codepoint_t> (u, 0x0E4Du, 0x0E4Eu)) |
| return AV; |
| if (hb_in_range<hb_codepoint_t> (u, 0x0E38u, 0x0E3Au)) |
| return BV; |
| if (hb_in_range<hb_codepoint_t> (u, 0x0E48u, 0x0E4Cu)) |
| return T; |
| return NOT_MARK; |
| } |
| |
| |
| enum thai_action_t |
| { |
| NOP, |
| SD, /* Shift combining-mark down */ |
| SL, /* Shift combining-mark left */ |
| SDL, /* Shift combining-mark down-left */ |
| RD /* Remove descender from base */ |
| }; |
| |
| static hb_codepoint_t |
| thai_pua_shape (hb_codepoint_t u, thai_action_t action, hb_font_t *font) |
| { |
| struct thai_pua_mapping_t { |
| hb_codepoint_t u; |
| hb_codepoint_t win_pua; |
| hb_codepoint_t mac_pua; |
| } const *pua_mappings = nullptr; |
| static const thai_pua_mapping_t SD_mappings[] = { |
| {0x0E48u, 0xF70Au, 0xF88Bu}, /* MAI EK */ |
| {0x0E49u, 0xF70Bu, 0xF88Eu}, /* MAI THO */ |
| {0x0E4Au, 0xF70Cu, 0xF891u}, /* MAI TRI */ |
| {0x0E4Bu, 0xF70Du, 0xF894u}, /* MAI CHATTAWA */ |
| {0x0E4Cu, 0xF70Eu, 0xF897u}, /* THANTHAKHAT */ |
| {0x0E38u, 0xF718u, 0xF89Bu}, /* SARA U */ |
| {0x0E39u, 0xF719u, 0xF89Cu}, /* SARA UU */ |
| {0x0E3Au, 0xF71Au, 0xF89Du}, /* PHINTHU */ |
| {0x0000u, 0x0000u, 0x0000u} |
| }; |
| static const thai_pua_mapping_t SDL_mappings[] = { |
| {0x0E48u, 0xF705u, 0xF88Cu}, /* MAI EK */ |
| {0x0E49u, 0xF706u, 0xF88Fu}, /* MAI THO */ |
| {0x0E4Au, 0xF707u, 0xF892u}, /* MAI TRI */ |
| {0x0E4Bu, 0xF708u, 0xF895u}, /* MAI CHATTAWA */ |
| {0x0E4Cu, 0xF709u, 0xF898u}, /* THANTHAKHAT */ |
| {0x0000u, 0x0000u, 0x0000u} |
| }; |
| static const thai_pua_mapping_t SL_mappings[] = { |
| {0x0E48u, 0xF713u, 0xF88Au}, /* MAI EK */ |
| {0x0E49u, 0xF714u, 0xF88Du}, /* MAI THO */ |
| {0x0E4Au, 0xF715u, 0xF890u}, /* MAI TRI */ |
| {0x0E4Bu, 0xF716u, 0xF893u}, /* MAI CHATTAWA */ |
| {0x0E4Cu, 0xF717u, 0xF896u}, /* THANTHAKHAT */ |
| {0x0E31u, 0xF710u, 0xF884u}, /* MAI HAN-AKAT */ |
| {0x0E34u, 0xF701u, 0xF885u}, /* SARA I */ |
| {0x0E35u, 0xF702u, 0xF886u}, /* SARA II */ |
| {0x0E36u, 0xF703u, 0xF887u}, /* SARA UE */ |
| {0x0E37u, 0xF704u, 0xF888u}, /* SARA UEE */ |
| {0x0E47u, 0xF712u, 0xF889u}, /* MAITAIKHU */ |
| {0x0E4Du, 0xF711u, 0xF899u}, /* NIKHAHIT */ |
| {0x0000u, 0x0000u, 0x0000u} |
| }; |
| static const thai_pua_mapping_t RD_mappings[] = { |
| {0x0E0Du, 0xF70Fu, 0xF89Au}, /* YO YING */ |
| {0x0E10u, 0xF700u, 0xF89Eu}, /* THO THAN */ |
| {0x0000u, 0x0000u, 0x0000u} |
| }; |
| |
| switch (action) { |
| case NOP: return u; |
| case SD: pua_mappings = SD_mappings; break; |
| case SDL: pua_mappings = SDL_mappings; break; |
| case SL: pua_mappings = SL_mappings; break; |
| case RD: pua_mappings = RD_mappings; break; |
| } |
| for (; pua_mappings->u; pua_mappings++) |
| if (pua_mappings->u == u) |
| { |
| hb_codepoint_t glyph; |
| if (hb_font_get_glyph (font, pua_mappings->win_pua, 0, &glyph)) |
| return pua_mappings->win_pua; |
| if (hb_font_get_glyph (font, pua_mappings->mac_pua, 0, &glyph)) |
| return pua_mappings->mac_pua; |
| break; |
| } |
| return u; |
| } |
| |
| |
| static enum thai_above_state_t |
| { /* Cluster above looks like: */ |
| T0, /* ⣤ */ |
| T1, /* ⣼ */ |
| T2, /* ⣾ */ |
| T3, /* ⣿ */ |
| NUM_ABOVE_STATES |
| } thai_above_start_state[NUM_CONSONANT_TYPES + 1/* For NOT_CONSONANT */] = |
| { |
| T0, /* NC */ |
| T1, /* AC */ |
| T0, /* RC */ |
| T0, /* DC */ |
| T3, /* NOT_CONSONANT */ |
| }; |
| |
| static const struct thai_above_state_machine_edge_t { |
| thai_action_t action; |
| thai_above_state_t next_state; |
| } thai_above_state_machine[NUM_ABOVE_STATES][NUM_MARK_TYPES] = |
| { /*AV*/ /*BV*/ /*T*/ |
| /*T0*/ {{NOP,T3}, {NOP,T0}, {SD, T3}}, |
| /*T1*/ {{SL, T2}, {NOP,T1}, {SDL,T2}}, |
| /*T2*/ {{NOP,T3}, {NOP,T2}, {SL, T3}}, |
| /*T3*/ {{NOP,T3}, {NOP,T3}, {NOP,T3}}, |
| }; |
| |
| |
| static enum thai_below_state_t |
| { |
| B0, /* No descender */ |
| B1, /* Removable descender */ |
| B2, /* Strict descender */ |
| NUM_BELOW_STATES |
| } thai_below_start_state[NUM_CONSONANT_TYPES + 1/* For NOT_CONSONANT */] = |
| { |
| B0, /* NC */ |
| B0, /* AC */ |
| B1, /* RC */ |
| B2, /* DC */ |
| B2, /* NOT_CONSONANT */ |
| }; |
| |
| static const struct thai_below_state_machine_edge_t { |
| thai_action_t action; |
| thai_below_state_t next_state; |
| } thai_below_state_machine[NUM_BELOW_STATES][NUM_MARK_TYPES] = |
| { /*AV*/ /*BV*/ /*T*/ |
| /*B0*/ {{NOP,B0}, {NOP,B2}, {NOP, B0}}, |
| /*B1*/ {{NOP,B1}, {RD, B2}, {NOP, B1}}, |
| /*B2*/ {{NOP,B2}, {SD, B2}, {NOP, B2}}, |
| }; |
| |
| |
| static void |
| do_thai_pua_shaping (const hb_ot_shape_plan_t *plan HB_UNUSED, |
| hb_buffer_t *buffer, |
| hb_font_t *font) |
| { |
| #ifdef HB_NO_OT_SHAPER_THAI_FALLBACK |
| return; |
| #endif |
| |
| thai_above_state_t above_state = thai_above_start_state[NOT_CONSONANT]; |
| thai_below_state_t below_state = thai_below_start_state[NOT_CONSONANT]; |
| unsigned int base = 0; |
| |
| hb_glyph_info_t *info = buffer->info; |
| unsigned int count = buffer->len; |
| for (unsigned int i = 0; i < count; i++) |
| { |
| thai_mark_type_t mt = get_mark_type (info[i].codepoint); |
| |
| if (mt == NOT_MARK) { |
| thai_consonant_type_t ct = get_consonant_type (info[i].codepoint); |
| above_state = thai_above_start_state[ct]; |
| below_state = thai_below_start_state[ct]; |
| base = i; |
| continue; |
| } |
| |
| const thai_above_state_machine_edge_t &above_edge = thai_above_state_machine[above_state][mt]; |
| const thai_below_state_machine_edge_t &below_edge = thai_below_state_machine[below_state][mt]; |
| above_state = above_edge.next_state; |
| below_state = below_edge.next_state; |
| |
| /* At least one of the above/below actions is NOP. */ |
| thai_action_t action = above_edge.action != NOP ? above_edge.action : below_edge.action; |
| |
| buffer->unsafe_to_break (base, i); |
| if (action == RD) |
| info[base].codepoint = thai_pua_shape (info[base].codepoint, action, font); |
| else |
| info[i].codepoint = thai_pua_shape (info[i].codepoint, action, font); |
| } |
| } |
| |
| |
| static void |
| preprocess_text_thai (const hb_ot_shape_plan_t *plan, |
| hb_buffer_t *buffer, |
| hb_font_t *font) |
| { |
| /* This function implements the shaping logic documented here: |
| * |
| * https://linux.thai.net/~thep/th-otf/shaping.html |
| * |
| * The first shaping rule listed there is needed even if the font has Thai |
| * OpenType tables. The rest do fallback positioning based on PUA codepoints. |
| * We implement that only if there exist no Thai GSUB in the font. |
| */ |
| |
| /* The following is NOT specified in the MS OT Thai spec, however, it seems |
| * to be what Uniscribe and other engines implement. According to Eric Muller: |
| * |
| * When you have a SARA AM, decompose it in NIKHAHIT + SARA AA, *and* move the |
| * NIKHAHIT backwards over any above-base marks. |
| * |
| * <0E14, 0E4B, 0E33> -> <0E14, 0E4D, 0E4B, 0E32> |
| * |
| * This reordering is legit only when the NIKHAHIT comes from a SARA AM, not |
| * when it's there to start with. The string <0E14, 0E4B, 0E4D> is probably |
| * not what a user wanted, but the rendering is nevertheless nikhahit above |
| * chattawa. |
| * |
| * Same for Lao. |
| * |
| * Note: |
| * |
| * Uniscribe also does some below-marks reordering. Namely, it positions U+0E3A |
| * after U+0E38 and U+0E39. We do that by modifying the ccc for U+0E3A. |
| * See unicode->modified_combining_class (). Lao does NOT have a U+0E3A |
| * equivalent. |
| */ |
| |
| |
| /* |
| * Here are the characters of significance: |
| * |
| * Thai Lao |
| * SARA AM: U+0E33 U+0EB3 |
| * SARA AA: U+0E32 U+0EB2 |
| * Nikhahit: U+0E4D U+0ECD |
| * |
| * Testing shows that Uniscribe reorder the following marks: |
| * Thai: <0E31,0E34..0E37, 0E47..0E4E> |
| * Lao: <0EB1,0EB4..0EB7,0EBB,0EC8..0ECD> |
| * |
| * Note how the Lao versions are the same as Thai + 0x80. |
| */ |
| |
| /* We only get one script at a time, so a script-agnostic implementation |
| * is adequate here. */ |
| #define IS_SARA_AM(x) (((x) & ~0x0080u) == 0x0E33u) |
| #define NIKHAHIT_FROM_SARA_AM(x) ((x) - 0x0E33u + 0x0E4Du) |
| #define SARA_AA_FROM_SARA_AM(x) ((x) - 1) |
| #define IS_ABOVE_BASE_MARK(x) (hb_in_ranges<hb_codepoint_t> ((x) & ~0x0080u, 0x0E34u, 0x0E37u, 0x0E47u, 0x0E4Eu, 0x0E31u, 0x0E31u, 0x0E3Bu, 0x0E3Bu)) |
| |
| buffer->clear_output (); |
| unsigned int count = buffer->len; |
| for (buffer->idx = 0; buffer->idx < count /* No need for: && buffer->successful */;) |
| { |
| hb_codepoint_t u = buffer->cur().codepoint; |
| if (likely (!IS_SARA_AM (u))) |
| { |
| if (unlikely (!buffer->next_glyph ())) break; |
| continue; |
| } |
| |
| /* Is SARA AM. Decompose and reorder. */ |
| (void) buffer->output_glyph (NIKHAHIT_FROM_SARA_AM (u)); |
| _hb_glyph_info_set_continuation (&buffer->prev()); |
| if (unlikely (!buffer->replace_glyph (SARA_AA_FROM_SARA_AM (u)))) break; |
| |
| /* Make Nikhahit be recognized as a ccc=0 mark when zeroing widths. */ |
| unsigned int end = buffer->out_len; |
| _hb_glyph_info_set_general_category (&buffer->out_info[end - 2], HB_UNICODE_GENERAL_CATEGORY_NON_SPACING_MARK); |
| |
| /* Ok, let's see... */ |
| unsigned int start = end - 2; |
| while (start > 0 && IS_ABOVE_BASE_MARK (buffer->out_info[start - 1].codepoint)) |
| start--; |
| |
| if (start + 2 < end) |
| { |
| /* Move Nikhahit (end-2) to the beginning */ |
| buffer->merge_out_clusters (start, end); |
| hb_glyph_info_t t = buffer->out_info[end - 2]; |
| memmove (buffer->out_info + start + 1, |
| buffer->out_info + start, |
| sizeof (buffer->out_info[0]) * (end - start - 2)); |
| buffer->out_info[start] = t; |
| } |
| else |
| { |
| /* Since we decomposed, and NIKHAHIT is combining, merge clusters with the |
| * previous cluster. */ |
| if (start && buffer->cluster_level == HB_BUFFER_CLUSTER_LEVEL_MONOTONE_GRAPHEMES) |
| buffer->merge_out_clusters (start - 1, end); |
| } |
| } |
| buffer->sync (); |
| |
| /* If font has Thai GSUB, we are done. */ |
| if (plan->props.script == HB_SCRIPT_THAI && !plan->map.found_script[0]) |
| do_thai_pua_shaping (plan, buffer, font); |
| } |
| |
| const hb_ot_shaper_t _hb_ot_shaper_thai = |
| { |
| nullptr, /* collect_features */ |
| nullptr, /* override_features */ |
| nullptr, /* data_create */ |
| nullptr, /* data_destroy */ |
| preprocess_text_thai, |
| nullptr, /* postprocess_glyphs */ |
| nullptr, /* decompose */ |
| nullptr, /* compose */ |
| nullptr, /* setup_masks */ |
| nullptr, /* reorder_marks */ |
| HB_TAG_NONE, /* gpos_tag */ |
| HB_OT_SHAPE_NORMALIZATION_MODE_DEFAULT, |
| HB_OT_SHAPE_ZERO_WIDTH_MARKS_BY_GDEF_LATE, |
| false,/* fallback_position */ |
| }; |
| |
| |
| #endif |