/* * 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-private.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 (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 (u, 0x0E34u, 0x0E37u) || u == 0x0E47u || hb_in_range (u, 0x0E4Du, 0x0E4Eu)) return AV; if (hb_in_range (u, 0x0E38u, 0x0E3Au)) return BV; if (hb_in_range (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 = NULL; 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) { 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; 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: * * http://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 tone mark (0E48-0E4B). * * <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..0EB7,0EC7..0ECE> * * 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_TONE_MARK(x) (hb_in_ranges ((x) & ~0x0080u, 0x0E34u, 0x0E37u, 0x0E47u, 0x0E4Eu, 0x0E31u, 0x0E31u)) buffer->clear_output (); unsigned int count = buffer->len; for (buffer->idx = 0; buffer->idx < count && !buffer->in_error;) { hb_codepoint_t u = buffer->cur().codepoint; if (likely (!IS_SARA_AM (u))) { buffer->next_glyph (); continue; } /* Is SARA AM. Decompose and reorder. */ hb_codepoint_t decomposed[2] = {hb_codepoint_t (NIKHAHIT_FROM_SARA_AM (u)), hb_codepoint_t (SARA_AA_FROM_SARA_AM (u))}; buffer->replace_glyphs (1, 2, decomposed); if (unlikely (buffer->in_error)) return; /* 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_TONE_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->swap_buffers (); /* 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_complex_shaper_t _hb_ot_complex_shaper_thai = { "thai", NULL, /* collect_features */ NULL, /* override_features */ NULL, /* data_create */ NULL, /* data_destroy */ preprocess_text_thai, NULL, /* postprocess_glyphs */ HB_OT_SHAPE_NORMALIZATION_MODE_DEFAULT, NULL, /* decompose */ NULL, /* compose */ NULL, /* setup_masks */ NULL, /* disable_otl */ HB_OT_SHAPE_ZERO_WIDTH_MARKS_BY_GDEF_LATE, false,/* fallback_position */ };