943 lines
30 KiB
C++
943 lines
30 KiB
C++
/*
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* Copyright © 2011,2012 Google, Inc.
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*
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* This is part of HarfBuzz, a text shaping library.
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*
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* Permission is hereby granted, without written agreement and without
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* license or royalty fees, to use, copy, modify, and distribute this
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* software and its documentation for any purpose, provided that the
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* above copyright notice and the following two paragraphs appear in
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* all copies of this software.
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*
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* IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
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* DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
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* ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
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* IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
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* DAMAGE.
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*
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* THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
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* BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
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* FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
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* ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
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* PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
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*
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* Google Author(s): Behdad Esfahbod
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*/
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#include "hb-ot-shape-complex-indic-private.hh"
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#include "hb-ot-shape-private.hh"
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#define OLD_INDIC_TAG(script) (((hb_tag_t) script) | 0x20000000)
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#define IS_OLD_INDIC_TAG(tag) ( \
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(tag) == OLD_INDIC_TAG (HB_SCRIPT_BENGALI) || \
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(tag) == OLD_INDIC_TAG (HB_SCRIPT_DEVANAGARI) || \
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(tag) == OLD_INDIC_TAG (HB_SCRIPT_GUJARATI) || \
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(tag) == OLD_INDIC_TAG (HB_SCRIPT_GURMUKHI) || \
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(tag) == OLD_INDIC_TAG (HB_SCRIPT_KANNADA) || \
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(tag) == OLD_INDIC_TAG (HB_SCRIPT_MALAYALAM) || \
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(tag) == OLD_INDIC_TAG (HB_SCRIPT_ORIYA) || \
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(tag) == OLD_INDIC_TAG (HB_SCRIPT_TAMIL) || \
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(tag) == OLD_INDIC_TAG (HB_SCRIPT_TELUGU) \
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)
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struct indic_options_t
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{
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int initialized : 1;
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int uniscribe_bug_compatible : 1;
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};
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union indic_options_union_t {
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int i;
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indic_options_t opts;
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};
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ASSERT_STATIC (sizeof (int) == sizeof (indic_options_union_t));
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static indic_options_union_t
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indic_options_init (void)
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{
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indic_options_union_t u;
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u.i = 0;
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u.opts.initialized = 1;
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char *c = getenv ("HB_OT_INDIC_OPTIONS");
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u.opts.uniscribe_bug_compatible = c && strstr (c, "uniscribe-bug-compatible");
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return u;
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}
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inline indic_options_t
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indic_options (void)
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{
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static indic_options_union_t options;
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if (unlikely (!options.i)) {
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/* This is idempotent and threadsafe. */
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options = indic_options_init ();
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}
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return options.opts;
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}
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static int
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compare_codepoint (const void *pa, const void *pb)
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{
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hb_codepoint_t a = * (hb_codepoint_t *) pa;
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hb_codepoint_t b = * (hb_codepoint_t *) pb;
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return a < b ? -1 : a == b ? 0 : +1;
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}
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static indic_position_t
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consonant_position (hb_codepoint_t u)
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{
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consonant_position_t *record;
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/* Khmer does not have pre-base half forms. */
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if (0x1780 <= u && u <= 0x17FF)
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return POS_BELOW_C;
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record = (consonant_position_t *) bsearch (&u, consonant_positions,
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ARRAY_LENGTH (consonant_positions),
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sizeof (consonant_positions[0]),
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compare_codepoint);
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return record ? record->position : POS_BASE_C;
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}
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static bool
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is_ra (hb_codepoint_t u)
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{
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return !!bsearch (&u, ra_chars,
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ARRAY_LENGTH (ra_chars),
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sizeof (ra_chars[0]),
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compare_codepoint);
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}
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static bool
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is_joiner (const hb_glyph_info_t &info)
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{
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return !!(FLAG (info.indic_category()) & (FLAG (OT_ZWJ) | FLAG (OT_ZWNJ)));
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}
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static bool
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is_consonant (const hb_glyph_info_t &info)
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{
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/* Note:
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*
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* We treat Vowels and placeholders as if they were consonants. This is safe because Vowels
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* cannot happen in a consonant syllable. The plus side however is, we can call the
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* consonant syllable logic from the vowel syllable function and get it all right! */
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return !!(FLAG (info.indic_category()) & (FLAG (OT_C) | FLAG (OT_Ra) | FLAG (OT_V) | FLAG (OT_NBSP) | FLAG (OT_DOTTEDCIRCLE)));
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}
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struct feature_list_t {
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hb_tag_t tag;
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hb_bool_t is_global;
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};
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static const feature_list_t
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indic_basic_features[] =
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{
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{HB_TAG('n','u','k','t'), true},
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{HB_TAG('a','k','h','n'), false},
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{HB_TAG('r','p','h','f'), false},
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{HB_TAG('r','k','r','f'), true},
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{HB_TAG('p','r','e','f'), false},
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{HB_TAG('b','l','w','f'), false},
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{HB_TAG('h','a','l','f'), false},
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{HB_TAG('a','b','v','f'), false},
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{HB_TAG('p','s','t','f'), false},
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{HB_TAG('c','j','c','t'), false},
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{HB_TAG('v','a','t','u'), true},
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};
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/* Same order as the indic_basic_features array */
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enum {
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_NUKT,
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AKHN,
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RPHF,
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_RKRF,
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PREF,
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BLWF,
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HALF,
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ABVF,
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PSTF,
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CJCT,
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VATU
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};
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static const feature_list_t
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indic_other_features[] =
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{
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{HB_TAG('i','n','i','t'), false},
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{HB_TAG('p','r','e','s'), true},
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{HB_TAG('a','b','v','s'), true},
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{HB_TAG('b','l','w','s'), true},
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{HB_TAG('p','s','t','s'), true},
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{HB_TAG('h','a','l','n'), true},
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{HB_TAG('d','i','s','t'), true},
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{HB_TAG('a','b','v','m'), true},
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{HB_TAG('b','l','w','m'), true},
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};
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static void
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initial_reordering (const hb_ot_map_t *map,
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hb_face_t *face,
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hb_buffer_t *buffer,
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void *user_data HB_UNUSED);
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static void
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final_reordering (const hb_ot_map_t *map,
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hb_face_t *face,
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hb_buffer_t *buffer,
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void *user_data HB_UNUSED);
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void
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_hb_ot_shape_complex_collect_features_indic (hb_ot_map_builder_t *map,
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const hb_segment_properties_t *props HB_UNUSED)
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{
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map->add_bool_feature (HB_TAG('l','o','c','l'));
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/* The Indic specs do not require ccmp, but we apply it here since if
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* there is a use of it, it's typically at the beginning. */
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map->add_bool_feature (HB_TAG('c','c','m','p'));
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map->add_gsub_pause (initial_reordering, NULL);
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for (unsigned int i = 0; i < ARRAY_LENGTH (indic_basic_features); i++) {
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map->add_bool_feature (indic_basic_features[i].tag, indic_basic_features[i].is_global);
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map->add_gsub_pause (NULL, NULL);
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}
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map->add_gsub_pause (final_reordering, NULL);
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for (unsigned int i = 0; i < ARRAY_LENGTH (indic_other_features); i++) {
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map->add_bool_feature (indic_other_features[i].tag, indic_other_features[i].is_global);
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map->add_gsub_pause (NULL, NULL);
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}
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}
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void
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_hb_ot_shape_complex_override_features_indic (hb_ot_map_builder_t *map,
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const hb_segment_properties_t *props HB_UNUSED)
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{
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/* Uniscribe does not apply 'kern'. */
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if (indic_options ().uniscribe_bug_compatible)
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map->add_feature (HB_TAG('k','e','r','n'), 0, true);
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}
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hb_ot_shape_normalization_mode_t
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_hb_ot_shape_complex_normalization_preference_indic (void)
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{
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/* We want split matras decomposed by the common shaping logic. */
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return HB_OT_SHAPE_NORMALIZATION_MODE_DECOMPOSED;
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}
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void
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_hb_ot_shape_complex_setup_masks_indic (hb_ot_map_t *map HB_UNUSED,
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hb_buffer_t *buffer,
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hb_font_t *font HB_UNUSED)
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{
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HB_BUFFER_ALLOCATE_VAR (buffer, indic_category);
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HB_BUFFER_ALLOCATE_VAR (buffer, indic_position);
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/* We cannot setup masks here. We save information about characters
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* and setup masks later on in a pause-callback. */
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unsigned int count = buffer->len;
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for (unsigned int i = 0; i < count; i++)
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{
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hb_glyph_info_t &info = buffer->info[i];
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unsigned int type = get_indic_categories (info.codepoint);
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info.indic_category() = type & 0x0F;
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info.indic_position() = type >> 4;
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/* The spec says U+0952 is OT_A. However, testing shows that Uniscribe
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* treats U+0951..U+0952 all as OT_VD.
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* TESTS:
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* U+092E,U+0947,U+0952
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* U+092E,U+0952,U+0947
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* U+092E,U+0947,U+0951
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* U+092E,U+0951,U+0947
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* */
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if (unlikely (hb_in_range<hb_codepoint_t> (info.codepoint, 0x0951, 0x0954)))
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info.indic_category() = OT_VD;
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if (info.indic_category() == OT_X &&
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unlikely (hb_in_range<hb_codepoint_t> (info.codepoint, 0x17CB, 0x17D0)))
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info.indic_category() = OT_RS;
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if (info.indic_category() == OT_C) {
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info.indic_position() = consonant_position (info.codepoint);
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if (is_ra (info.codepoint))
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info.indic_category() = OT_Ra;
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} else if (info.indic_category() == OT_RS) {
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info.indic_position() = POS_ABOVE_M;
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} else if (info.indic_category() == OT_SM ||
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info.indic_category() == OT_VD) {
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info.indic_position() = POS_SMVD;
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} else if (unlikely (info.codepoint == 0x200C))
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info.indic_category() = OT_ZWNJ;
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else if (unlikely (info.codepoint == 0x200D))
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info.indic_category() = OT_ZWJ;
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else if (unlikely (info.codepoint == 0x25CC))
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info.indic_category() = OT_DOTTEDCIRCLE;
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}
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}
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static int
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compare_indic_order (const hb_glyph_info_t *pa, const hb_glyph_info_t *pb)
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{
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int a = pa->indic_position();
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int b = pb->indic_position();
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return a < b ? -1 : a == b ? 0 : +1;
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}
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/* Rules from:
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* https://www.microsoft.com/typography/otfntdev/devanot/shaping.aspx */
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static void
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initial_reordering_consonant_syllable (const hb_ot_map_t *map, hb_buffer_t *buffer, hb_mask_t *basic_mask_array,
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unsigned int start, unsigned int end)
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{
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hb_glyph_info_t *info = buffer->info;
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/* 1. Find base consonant:
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*
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* The shaping engine finds the base consonant of the syllable, using the
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* following algorithm: starting from the end of the syllable, move backwards
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* until a consonant is found that does not have a below-base or post-base
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* form (post-base forms have to follow below-base forms), or that is not a
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* pre-base reordering Ra, or arrive at the first consonant. The consonant
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* stopped at will be the base.
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*
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* o If the syllable starts with Ra + Halant (in a script that has Reph)
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* and has more than one consonant, Ra is excluded from candidates for
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* base consonants.
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*/
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unsigned int base = end;
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bool has_reph = false;
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{
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/* -> If the syllable starts with Ra + Halant (in a script that has Reph)
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* and has more than one consonant, Ra is excluded from candidates for
|
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* base consonants. */
|
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unsigned int limit = start;
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if (basic_mask_array[RPHF] &&
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start + 3 <= end &&
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info[start].indic_category() == OT_Ra &&
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info[start + 1].indic_category() == OT_H &&
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!is_joiner (info[start + 2]))
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{
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limit += 2;
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base = start;
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has_reph = true;
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};
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/* -> starting from the end of the syllable, move backwards */
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unsigned int i = end;
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do {
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i--;
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/* -> until a consonant is found */
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if (is_consonant (info[i]))
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{
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/* -> that does not have a below-base or post-base form
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* (post-base forms have to follow below-base forms), */
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if (info[i].indic_position() != POS_BELOW_C &&
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info[i].indic_position() != POS_POST_C)
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{
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base = i;
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break;
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}
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/* -> or that is not a pre-base reordering Ra,
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*
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* TODO
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*/
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||
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/* -> or arrive at the first consonant. The consonant stopped at will
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* be the base. */
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base = i;
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}
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else
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if (is_joiner (info[i]))
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break;
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} while (i > limit);
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if (base < start)
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base = start; /* Just in case... */
|
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|
||
|
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/* -> If the syllable starts with Ra + Halant (in a script that has Reph)
|
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* and has more than one consonant, Ra is excluded from candidates for
|
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* base consonants. */
|
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if (has_reph && base == start) {
|
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/* Have no other consonant, so Reph is not formed and Ra becomes base. */
|
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has_reph = false;
|
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}
|
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}
|
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|
||
|
||
/* 2. Decompose and reorder Matras:
|
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*
|
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* Each matra and any syllable modifier sign in the cluster are moved to the
|
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* appropriate position relative to the consonant(s) in the cluster. The
|
||
* shaping engine decomposes two- or three-part matras into their constituent
|
||
* parts before any repositioning. Matra characters are classified by which
|
||
* consonant in a conjunct they have affinity for and are reordered to the
|
||
* following positions:
|
||
*
|
||
* o Before first half form in the syllable
|
||
* o After subjoined consonants
|
||
* o After post-form consonant
|
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* o After main consonant (for above marks)
|
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*
|
||
* IMPLEMENTATION NOTES:
|
||
*
|
||
* The normalize() routine has already decomposed matras for us, so we don't
|
||
* need to worry about that.
|
||
*/
|
||
|
||
|
||
/* 3. Reorder marks to canonical order:
|
||
*
|
||
* Adjacent nukta and halant or nukta and vedic sign are always repositioned
|
||
* if necessary, so that the nukta is first.
|
||
*
|
||
* IMPLEMENTATION NOTES:
|
||
*
|
||
* We don't need to do this: the normalize() routine already did this for us.
|
||
*/
|
||
|
||
|
||
/* Reorder characters */
|
||
|
||
for (unsigned int i = start; i < base; i++)
|
||
info[i].indic_position() = POS_PRE_C;
|
||
info[base].indic_position() = POS_BASE_C;
|
||
|
||
/* Handle beginning Ra */
|
||
if (has_reph)
|
||
info[start].indic_position() = POS_RA_TO_BECOME_REPH;
|
||
|
||
/* For old-style Indic script tags, move the first post-base Halant after
|
||
* last consonant. */
|
||
if (IS_OLD_INDIC_TAG (map->get_chosen_script (0))) {
|
||
for (unsigned int i = base + 1; i < end; i++)
|
||
if (info[i].indic_category() == OT_H) {
|
||
unsigned int j;
|
||
for (j = end - 1; j > i; j--)
|
||
if (is_consonant (info[j]))
|
||
break;
|
||
if (j > i) {
|
||
/* Move Halant to after last consonant. */
|
||
hb_glyph_info_t t = info[i];
|
||
memmove (&info[i], &info[i + 1], (j - i) * sizeof (info[0]));
|
||
info[j] = t;
|
||
}
|
||
break;
|
||
}
|
||
}
|
||
|
||
/* Attach ZWJ, ZWNJ, nukta, and halant to previous char to move with them. */
|
||
if (!indic_options ().uniscribe_bug_compatible)
|
||
{
|
||
/* Please update the Uniscribe branch when touching this! */
|
||
for (unsigned int i = start + 1; i < end; i++)
|
||
if ((FLAG (info[i].indic_category()) & (FLAG (OT_ZWNJ) | FLAG (OT_ZWJ) | FLAG (OT_N) | FLAG (OT_H))))
|
||
info[i].indic_position() = info[i - 1].indic_position();
|
||
} else {
|
||
/*
|
||
* Uniscribe doesn't move the Halant with Left Matra.
|
||
* TEST: U+092B,U+093F,U+094DE
|
||
*/
|
||
/* Please update the non-Uniscribe branch when touching this! */
|
||
for (unsigned int i = start + 1; i < end; i++)
|
||
if ((FLAG (info[i].indic_category()) & (FLAG (OT_ZWNJ) | FLAG (OT_ZWJ) | FLAG (OT_N) | FLAG (OT_H)))) {
|
||
info[i].indic_position() = info[i - 1].indic_position();
|
||
if (info[i].indic_category() == OT_H && info[i].indic_position() == POS_PRE_M)
|
||
for (unsigned int j = i; j > start; j--)
|
||
if (info[j - 1].indic_position() != POS_PRE_M) {
|
||
info[i].indic_position() = info[j - 1].indic_position();
|
||
break;
|
||
}
|
||
}
|
||
}
|
||
|
||
/* We do bubble-sort, skip malicious clusters attempts */
|
||
if (end - start < 64)
|
||
{
|
||
/* Sit tight, rock 'n roll! */
|
||
hb_bubble_sort (info + start, end - start, compare_indic_order);
|
||
/* Find base again */
|
||
base = end;
|
||
for (unsigned int i = start; i < end; i++)
|
||
if (info[i].indic_position() == POS_BASE_C) {
|
||
base = i;
|
||
break;
|
||
}
|
||
}
|
||
|
||
/* Setup masks now */
|
||
|
||
{
|
||
hb_mask_t mask;
|
||
|
||
/* Reph */
|
||
for (unsigned int i = start; i < end && info[i].indic_position() == POS_RA_TO_BECOME_REPH; i++)
|
||
info[i].mask |= basic_mask_array[RPHF];
|
||
|
||
/* Pre-base */
|
||
mask = basic_mask_array[HALF] | basic_mask_array[AKHN] | basic_mask_array[CJCT];
|
||
for (unsigned int i = start; i < base; i++)
|
||
info[i].mask |= mask;
|
||
/* Base */
|
||
mask = basic_mask_array[AKHN] | basic_mask_array[CJCT];
|
||
info[base].mask |= mask;
|
||
/* Post-base */
|
||
mask = basic_mask_array[BLWF] | basic_mask_array[ABVF] | basic_mask_array[PSTF] | basic_mask_array[CJCT];
|
||
for (unsigned int i = base + 1; i < end; i++)
|
||
info[i].mask |= mask;
|
||
}
|
||
|
||
/* XXX This will not match for old-Indic spec since the Halant-Ra order is reversed already. */
|
||
if (basic_mask_array[PREF] && base + 3 <= end)
|
||
{
|
||
/* Find a Halant,Ra sequence and mark it fore pre-base reordering processing. */
|
||
for (unsigned int i = base + 1; i + 1 < end; i++)
|
||
if (info[i].indic_category() == OT_H &&
|
||
info[i + 1].indic_category() == OT_Ra)
|
||
{
|
||
info[i].mask |= basic_mask_array[PREF];
|
||
info[i + 1].mask |= basic_mask_array[PREF];
|
||
break;
|
||
}
|
||
}
|
||
|
||
/* Apply ZWJ/ZWNJ effects */
|
||
for (unsigned int i = start + 1; i < end; i++)
|
||
if (is_joiner (info[i])) {
|
||
bool non_joiner = info[i].indic_category() == OT_ZWNJ;
|
||
unsigned int j = i;
|
||
|
||
do {
|
||
j--;
|
||
|
||
info[j].mask &= ~basic_mask_array[CJCT];
|
||
if (non_joiner)
|
||
info[j].mask &= ~basic_mask_array[HALF];
|
||
|
||
} while (j > start && !is_consonant (info[j]));
|
||
}
|
||
}
|
||
|
||
|
||
static void
|
||
initial_reordering_vowel_syllable (const hb_ot_map_t *map,
|
||
hb_buffer_t *buffer,
|
||
hb_mask_t *basic_mask_array,
|
||
unsigned int start, unsigned int end)
|
||
{
|
||
/* We made the vowels look like consonants. So let's call the consonant logic! */
|
||
initial_reordering_consonant_syllable (map, buffer, basic_mask_array, start, end);
|
||
}
|
||
|
||
static void
|
||
initial_reordering_standalone_cluster (const hb_ot_map_t *map,
|
||
hb_buffer_t *buffer,
|
||
hb_mask_t *basic_mask_array,
|
||
unsigned int start, unsigned int end)
|
||
{
|
||
/* We treat NBSP/dotted-circle as if they are consonants, so we should just chain.
|
||
* Only if not in compatibility mode that is... */
|
||
|
||
if (indic_options ().uniscribe_bug_compatible)
|
||
{
|
||
/* For dotted-circle, this is what Uniscribe does:
|
||
* If dotted-circle is the last glyph, it just does nothing.
|
||
* Ie. It doesn't form Reph. */
|
||
if (buffer->info[end - 1].indic_category() == OT_DOTTEDCIRCLE)
|
||
return;
|
||
}
|
||
|
||
initial_reordering_consonant_syllable (map, buffer, basic_mask_array, start, end);
|
||
}
|
||
|
||
static void
|
||
initial_reordering_non_indic (const hb_ot_map_t *map HB_UNUSED,
|
||
hb_buffer_t *buffer HB_UNUSED,
|
||
hb_mask_t *basic_mask_array HB_UNUSED,
|
||
unsigned int start HB_UNUSED, unsigned int end HB_UNUSED)
|
||
{
|
||
/* Nothing to do right now. If we ever switch to using the output
|
||
* buffer in the reordering process, we'd need to next_glyph() here. */
|
||
}
|
||
|
||
#include "hb-ot-shape-complex-indic-machine.hh"
|
||
|
||
static void
|
||
initial_reordering (const hb_ot_map_t *map,
|
||
hb_face_t *face HB_UNUSED,
|
||
hb_buffer_t *buffer,
|
||
void *user_data HB_UNUSED)
|
||
{
|
||
hb_mask_t basic_mask_array[ARRAY_LENGTH (indic_basic_features)] = {0};
|
||
unsigned int num_masks = ARRAY_LENGTH (indic_basic_features);
|
||
for (unsigned int i = 0; i < num_masks; i++)
|
||
basic_mask_array[i] = map->get_1_mask (indic_basic_features[i].tag);
|
||
|
||
find_syllables (map, buffer, basic_mask_array);
|
||
}
|
||
|
||
static void
|
||
final_reordering_syllable (hb_buffer_t *buffer,
|
||
hb_mask_t init_mask, hb_mask_t pref_mask,
|
||
unsigned int start, unsigned int end)
|
||
{
|
||
hb_glyph_info_t *info = buffer->info;
|
||
|
||
/* 4. Final reordering:
|
||
*
|
||
* After the localized forms and basic shaping forms GSUB features have been
|
||
* applied (see below), the shaping engine performs some final glyph
|
||
* reordering before applying all the remaining font features to the entire
|
||
* cluster.
|
||
*/
|
||
|
||
/* Find base again */
|
||
unsigned int base = end;
|
||
for (unsigned int i = start; i < end; i++)
|
||
if (info[i].indic_position() == POS_BASE_C) {
|
||
base = i;
|
||
break;
|
||
}
|
||
|
||
unsigned int start_of_last_cluster = base;
|
||
|
||
/* o Reorder matras:
|
||
*
|
||
* If a pre-base matra character had been reordered before applying basic
|
||
* features, the glyph can be moved closer to the main consonant based on
|
||
* whether half-forms had been formed. Actual position for the matra is
|
||
* defined as “after last standalone halant glyph, after initial matra
|
||
* position and before the main consonant”. If ZWJ or ZWNJ follow this
|
||
* halant, position is moved after it.
|
||
*/
|
||
|
||
if (start < base) /* Otherwise there can't be any pre-base matra characters. */
|
||
{
|
||
unsigned int new_pos = base - 1;
|
||
while (new_pos > start &&
|
||
!(FLAG (info[new_pos].indic_category()) & (FLAG (OT_M) | FLAG (OT_H))))
|
||
new_pos--;
|
||
/* If we found no Halant we are done. Otherwise only proceed if the Halant does
|
||
* not belong to the Matra itself! */
|
||
if (info[new_pos].indic_category() == OT_H &&
|
||
info[new_pos].indic_position() != POS_PRE_M) {
|
||
/* -> If ZWJ or ZWNJ follow this halant, position is moved after it. */
|
||
if (new_pos + 1 < end && is_joiner (info[new_pos + 1]))
|
||
new_pos++;
|
||
|
||
/* Now go see if there's actually any matras... */
|
||
for (unsigned int i = new_pos; i > start; i--)
|
||
if (info[i - 1].indic_position () == POS_PRE_M)
|
||
{
|
||
unsigned int old_pos = i - 1;
|
||
hb_glyph_info_t tmp = info[old_pos];
|
||
memmove (&info[old_pos], &info[old_pos + 1], (new_pos - old_pos) * sizeof (info[0]));
|
||
info[new_pos] = tmp;
|
||
start_of_last_cluster = MIN (new_pos, start_of_last_cluster);
|
||
new_pos--;
|
||
}
|
||
}
|
||
}
|
||
|
||
|
||
/* o Reorder reph:
|
||
*
|
||
* Reph’s original position is always at the beginning of the syllable,
|
||
* (i.e. it is not reordered at the character reordering stage). However,
|
||
* it will be reordered according to the basic-forms shaping results.
|
||
* Possible positions for reph, depending on the script, are; after main,
|
||
* before post-base consonant forms, and after post-base consonant forms.
|
||
*/
|
||
|
||
/* If there's anything after the Ra that has the REPH pos, it ought to be halant.
|
||
* Which means that the font has failed to ligate the Reph. In which case, we
|
||
* shouldn't move. */
|
||
if (start + 1 < end &&
|
||
info[start].indic_position() == POS_RA_TO_BECOME_REPH &&
|
||
info[start + 1].indic_position() != POS_RA_TO_BECOME_REPH)
|
||
{
|
||
unsigned int new_reph_pos;
|
||
|
||
enum reph_position_t {
|
||
REPH_AFTER_MAIN,
|
||
REPH_BEFORE_SUBSCRIPT,
|
||
REPH_AFTER_SUBSCRIPT,
|
||
REPH_BEFORE_POSTSCRIPT,
|
||
REPH_AFTER_POSTSCRIPT
|
||
} reph_pos;
|
||
|
||
/* XXX Figure out old behavior too */
|
||
switch ((hb_tag_t) buffer->props.script)
|
||
{
|
||
case HB_SCRIPT_MALAYALAM:
|
||
case HB_SCRIPT_ORIYA:
|
||
reph_pos = REPH_AFTER_MAIN;
|
||
break;
|
||
|
||
case HB_SCRIPT_GURMUKHI:
|
||
reph_pos = REPH_BEFORE_SUBSCRIPT;
|
||
break;
|
||
|
||
case HB_SCRIPT_BENGALI:
|
||
reph_pos = REPH_AFTER_SUBSCRIPT;
|
||
break;
|
||
|
||
default:
|
||
case HB_SCRIPT_DEVANAGARI:
|
||
case HB_SCRIPT_GUJARATI:
|
||
reph_pos = REPH_BEFORE_POSTSCRIPT;
|
||
break;
|
||
|
||
case HB_SCRIPT_KANNADA:
|
||
case HB_SCRIPT_TAMIL:
|
||
case HB_SCRIPT_TELUGU:
|
||
reph_pos = REPH_AFTER_POSTSCRIPT;
|
||
break;
|
||
}
|
||
|
||
/* 1. If reph should be positioned after post-base consonant forms,
|
||
* proceed to step 5.
|
||
*/
|
||
if (reph_pos == REPH_AFTER_POSTSCRIPT)
|
||
{
|
||
goto reph_step_5;
|
||
}
|
||
|
||
/* 2. If the reph repositioning class is not after post-base: target
|
||
* position is after the first explicit halant glyph between the
|
||
* first post-reph consonant and last main consonant. If ZWJ or ZWNJ
|
||
* are following this halant, position is moved after it. If such
|
||
* position is found, this is the target position. Otherwise,
|
||
* proceed to the next step.
|
||
*
|
||
* Note: in old-implementation fonts, where classifications were
|
||
* fixed in shaping engine, there was no case where reph position
|
||
* will be found on this step.
|
||
*/
|
||
{
|
||
new_reph_pos = start + 1;
|
||
while (new_reph_pos < base && info[new_reph_pos].indic_category() != OT_H)
|
||
new_reph_pos++;
|
||
|
||
if (new_reph_pos < base && info[new_reph_pos].indic_category() == OT_H) {
|
||
/* ->If ZWJ or ZWNJ are following this halant, position is moved after it. */
|
||
if (new_reph_pos + 1 < base && is_joiner (info[new_reph_pos + 1]))
|
||
new_reph_pos++;
|
||
goto reph_move;
|
||
}
|
||
}
|
||
|
||
/* 3. If reph should be repositioned after the main consonant: find the
|
||
* first consonant not ligated with main, or find the first
|
||
* consonant that is not a potential pre-base reordering Ra.
|
||
*/
|
||
if (reph_pos == REPH_AFTER_MAIN)
|
||
{
|
||
new_reph_pos = base;
|
||
/* XXX Skip potential pre-base reordering Ra. */
|
||
while (new_reph_pos < end &&
|
||
!( FLAG (info[new_reph_pos + 1].indic_position()) & (FLAG (POS_BELOW_C) | FLAG (POS_POST_C) | FLAG (POS_POST_M) | FLAG (POS_SMVD))))
|
||
new_reph_pos++;
|
||
if (new_reph_pos < end)
|
||
goto reph_move;
|
||
}
|
||
|
||
/* 4. If reph should be positioned before post-base consonant, find
|
||
* first post-base classified consonant not ligated with main. If no
|
||
* consonant is found, the target position should be before the
|
||
* first matra, syllable modifier sign or vedic sign.
|
||
*/
|
||
/* This is our take on what step 4 is trying to say (and failing, BADLY). */
|
||
if (reph_pos == REPH_AFTER_SUBSCRIPT)
|
||
{
|
||
new_reph_pos = base;
|
||
while (new_reph_pos < end &&
|
||
!( FLAG (info[new_reph_pos + 1].indic_position()) & (FLAG (POS_POST_C) | FLAG (POS_POST_M) | FLAG (POS_SMVD))))
|
||
new_reph_pos++;
|
||
if (new_reph_pos < end)
|
||
goto reph_move;
|
||
}
|
||
|
||
/* 5. If no consonant is found in steps 3 or 4, move reph to a position
|
||
* immediately before the first post-base matra, syllable modifier
|
||
* sign or vedic sign that has a reordering class after the intended
|
||
* reph position. For example, if the reordering position for reph
|
||
* is post-main, it will skip above-base matras that also have a
|
||
* post-main position.
|
||
*/
|
||
reph_step_5:
|
||
{
|
||
/* XXX */
|
||
}
|
||
|
||
/* 6. Otherwise, reorder reph to the end of the syllable.
|
||
*/
|
||
{
|
||
new_reph_pos = end - 1;
|
||
while (new_reph_pos > start && info[new_reph_pos].indic_position() == POS_SMVD)
|
||
new_reph_pos--;
|
||
|
||
/*
|
||
* If the Reph is to be ending up after a Matra,Halant sequence,
|
||
* position it before that Halant so it can interact with the Matra.
|
||
* However, if it's a plain Consonant,Halant we shouldn't do that.
|
||
* Uniscribe doesn't do this.
|
||
* TEST: U+0930,U+094D,U+0915,U+094B,U+094D
|
||
*/
|
||
if (!indic_options ().uniscribe_bug_compatible &&
|
||
unlikely (info[new_reph_pos].indic_category() == OT_H)) {
|
||
for (unsigned int i = base + 1; i < new_reph_pos; i++)
|
||
if (info[i].indic_category() == OT_M) {
|
||
/* Ok, got it. */
|
||
new_reph_pos--;
|
||
}
|
||
}
|
||
goto reph_move;
|
||
}
|
||
|
||
reph_move:
|
||
{
|
||
/* Move */
|
||
hb_glyph_info_t reph = info[start];
|
||
memmove (&info[start], &info[start + 1], (new_reph_pos - start) * sizeof (info[0]));
|
||
info[new_reph_pos] = reph;
|
||
start_of_last_cluster = start; /* Yay, one big cluster! */
|
||
}
|
||
}
|
||
|
||
|
||
/* o Reorder pre-base reordering consonants:
|
||
*
|
||
* If a pre-base reordering consonant is found, reorder it according to
|
||
* the following rules:
|
||
*/
|
||
|
||
if (pref_mask && base + 1 < end) /* Otherwise there can't be any pre-base reordering Ra. */
|
||
{
|
||
for (unsigned int i = base + 1; i < end; i++)
|
||
if ((info[i].mask & pref_mask) != 0)
|
||
{
|
||
/* 1. Only reorder a glyph produced by substitution during application
|
||
* of the <pref> feature. (Note that a font may shape a Ra consonant with
|
||
* the feature generally but block it in certain contexts.)
|
||
*/
|
||
if (i + 1 == end || (info[i + 1].mask & pref_mask) == 0)
|
||
{
|
||
/*
|
||
* 2. Try to find a target position the same way as for pre-base matra.
|
||
* If it is found, reorder pre-base consonant glyph.
|
||
*
|
||
* 3. If position is not found, reorder immediately before main
|
||
* consonant.
|
||
*/
|
||
|
||
unsigned int new_pos = base;
|
||
while (new_pos > start + 1 &&
|
||
!(FLAG (info[new_pos - 1].indic_category()) & (FLAG (OT_M) | FLAG (OT_H))))
|
||
new_pos--;
|
||
|
||
if (new_pos > start && info[new_pos - 1].indic_category() == OT_H)
|
||
/* -> If ZWJ or ZWNJ follow this halant, position is moved after it. */
|
||
if (new_pos < end && is_joiner (info[new_pos]))
|
||
new_pos++;
|
||
|
||
{
|
||
unsigned int old_pos = i;
|
||
hb_glyph_info_t tmp = info[old_pos];
|
||
memmove (&info[new_pos + 1], &info[new_pos], (old_pos - new_pos) * sizeof (info[0]));
|
||
info[new_pos] = tmp;
|
||
start_of_last_cluster = MIN (new_pos, start_of_last_cluster);
|
||
}
|
||
}
|
||
|
||
break;
|
||
}
|
||
}
|
||
|
||
|
||
/* Apply 'init' to the Left Matra if it's a word start. */
|
||
if (info[start].indic_position () == POS_PRE_M &&
|
||
(!start ||
|
||
!(FLAG (_hb_glyph_info_get_general_category (&info[start - 1])) &
|
||
(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)))))
|
||
info[start].mask |= init_mask;
|
||
|
||
|
||
|
||
/* Finish off the clusters and go home! */
|
||
|
||
if (!indic_options ().uniscribe_bug_compatible)
|
||
{
|
||
/* This is what Uniscribe does. Ie. add cluster boundaries after Halant,ZWNJ.
|
||
* This means, half forms are submerged into the main consonants cluster.
|
||
* This is unnecessary, and makes cursor positioning harder, but that's what
|
||
* Uniscribe does. */
|
||
unsigned int cluster_start = start;
|
||
for (unsigned int i = start + 1; i < start_of_last_cluster; i++)
|
||
if (info[i - 1].indic_category() == OT_H && info[i].indic_category() == OT_ZWNJ) {
|
||
i++;
|
||
buffer->merge_clusters (cluster_start, i);
|
||
cluster_start = i;
|
||
}
|
||
start_of_last_cluster = cluster_start;
|
||
}
|
||
|
||
buffer->merge_clusters (start_of_last_cluster, end);
|
||
}
|
||
|
||
|
||
static void
|
||
final_reordering (const hb_ot_map_t *map,
|
||
hb_face_t *face HB_UNUSED,
|
||
hb_buffer_t *buffer,
|
||
void *user_data HB_UNUSED)
|
||
{
|
||
unsigned int count = buffer->len;
|
||
if (!count) return;
|
||
|
||
hb_mask_t init_mask = map->get_1_mask (HB_TAG('i','n','i','t'));
|
||
hb_mask_t pref_mask = map->get_1_mask (HB_TAG('p','r','e','f'));
|
||
|
||
hb_glyph_info_t *info = buffer->info;
|
||
unsigned int last = 0;
|
||
unsigned int last_syllable = info[0].syllable();
|
||
for (unsigned int i = 1; i < count; i++)
|
||
if (last_syllable != info[i].syllable()) {
|
||
final_reordering_syllable (buffer, init_mask, pref_mask, last, i);
|
||
last = i;
|
||
last_syllable = info[last].syllable();
|
||
}
|
||
final_reordering_syllable (buffer, init_mask, pref_mask, last, count);
|
||
|
||
HB_BUFFER_DEALLOCATE_VAR (buffer, indic_category);
|
||
HB_BUFFER_DEALLOCATE_VAR (buffer, indic_position);
|
||
}
|
||
|
||
|
||
|