/* * Copyright © 2010 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" /* TODO Add kana, and other small shapers here */ /* The default shaper *only* adds additional per-script features.*/ static const hb_tag_t hangul_features[] = { HB_TAG('l','j','m','o'), HB_TAG('v','j','m','o'), HB_TAG('t','j','m','o'), HB_TAG_NONE }; static const hb_tag_t tibetan_features[] = { HB_TAG('a','b','v','s'), HB_TAG('b','l','w','s'), HB_TAG('a','b','v','m'), HB_TAG('b','l','w','m'), HB_TAG_NONE }; static void collect_features_default (const hb_ot_complex_shaper_t *shaper, hb_ot_map_builder_t *map, const hb_segment_properties_t *props) { const hb_tag_t *script_features = NULL; switch ((hb_tag_t) props->script) { /* Unicode-1.1 additions */ case HB_SCRIPT_HANGUL: script_features = hangul_features; break; /* Unicode-2.0 additions */ case HB_SCRIPT_TIBETAN: script_features = tibetan_features; break; } for (; script_features && *script_features; script_features++) map->add_bool_feature (*script_features); } static hb_ot_shape_normalization_mode_t normalization_preference_default (const hb_ot_complex_shaper_t *shaper, const hb_segment_properties_t *props) { switch ((hb_tag_t) props->script) { /* Unicode-1.1 additions */ case HB_SCRIPT_HANGUL: return HB_OT_SHAPE_NORMALIZATION_MODE_COMPOSED_FULL; } return HB_OT_SHAPE_NORMALIZATION_MODE_COMPOSED_DIACRITICS; } const hb_ot_complex_shaper_t _hb_ot_complex_shaper_default = { "default", collect_features_default, NULL, /* override_features */ normalization_preference_default, NULL, /* setup_masks */ true, /* zero_width_attached_marks */ }; /* Thai / Lao shaper */ static void setup_masks_thai (const hb_ot_complex_shaper_t *shaper, const hb_ot_map_t *map, hb_buffer_t *buffer, hb_font_t *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 so 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 _hb_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) & ~0x0080) == 0x0E33) #define NIKHAHIT_FROM_SARA_AM(x) ((x) - 0xE33 + 0xE4D) #define SARA_AA_FROM_SARA_AM(x) ((x) - 1) #define IS_TONE_MARK(x) (hb_in_ranges ((x) & ~0x0080, 0x0E34, 0x0E37, 0x0E47, 0x0E4E, 0x0E31, 0x0E31)) buffer->clear_output (); unsigned int count = buffer->len; for (buffer->idx = 0; buffer->idx < count;) { 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; /* Ok, let's see... */ unsigned int end = buffer->out_len; 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->merge_out_clusters (start - 1, end); } } buffer->swap_buffers (); } const hb_ot_complex_shaper_t _hb_ot_complex_shaper_thai = { "thai", NULL, /* collect_features */ NULL, /* override_features */ NULL, /* normalization_preference */ setup_masks_thai, true, /* zero_width_attached_marks */ };