jdk

Форк
0
/
hb-ot-shaper-hangul.cc 
436 строк · 14.0 Кб
1
/*
2
 * Copyright © 2013  Google, Inc.
3
 *
4
 *  This is part of HarfBuzz, a text shaping library.
5
 *
6
 * Permission is hereby granted, without written agreement and without
7
 * license or royalty fees, to use, copy, modify, and distribute this
8
 * software and its documentation for any purpose, provided that the
9
 * above copyright notice and the following two paragraphs appear in
10
 * all copies of this software.
11
 *
12
 * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
13
 * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
14
 * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
15
 * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
16
 * DAMAGE.
17
 *
18
 * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
19
 * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
20
 * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
21
 * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
22
 * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
23
 *
24
 * Google Author(s): Behdad Esfahbod
25
 */
26

27
#include "hb.hh"
28

29
#ifndef HB_NO_OT_SHAPE
30

31
#include "hb-ot-shaper.hh"
32

33

34
/* Hangul shaper */
35

36

37
/* Same order as the feature array below */
38
enum {
39
  _JMO,
40

41
  LJMO,
42
  VJMO,
43
  TJMO,
44

45
  FIRST_HANGUL_FEATURE = LJMO,
46
  HANGUL_FEATURE_COUNT = TJMO + 1
47
};
48

49
static const hb_tag_t hangul_features[HANGUL_FEATURE_COUNT] =
50
{
51
  HB_TAG_NONE,
52
  HB_TAG('l','j','m','o'),
53
  HB_TAG('v','j','m','o'),
54
  HB_TAG('t','j','m','o')
55
};
56

57
static void
58
collect_features_hangul (hb_ot_shape_planner_t *plan)
59
{
60
  hb_ot_map_builder_t *map = &plan->map;
61

62
  for (unsigned int i = FIRST_HANGUL_FEATURE; i < HANGUL_FEATURE_COUNT; i++)
63
    map->add_feature (hangul_features[i]);
64
}
65

66
static void
67
override_features_hangul (hb_ot_shape_planner_t *plan)
68
{
69
  /* Uniscribe does not apply 'calt' for Hangul, and certain fonts
70
   * (Noto Sans CJK, Source Sans Han, etc) apply all of jamo lookups
71
   * in calt, which is not desirable. */
72
  plan->map.disable_feature (HB_TAG('c','a','l','t'));
73
}
74

75
struct hangul_shape_plan_t
76
{
77
  hb_mask_t mask_array[HANGUL_FEATURE_COUNT];
78
};
79

80
static void *
81
data_create_hangul (const hb_ot_shape_plan_t *plan)
82
{
83
  hangul_shape_plan_t *hangul_plan = (hangul_shape_plan_t *) hb_calloc (1, sizeof (hangul_shape_plan_t));
84
  if (unlikely (!hangul_plan))
85
    return nullptr;
86

87
  for (unsigned int i = 0; i < HANGUL_FEATURE_COUNT; i++)
88
    hangul_plan->mask_array[i] = plan->map.get_1_mask (hangul_features[i]);
89

90
  return hangul_plan;
91
}
92

93
static void
94
data_destroy_hangul (void *data)
95
{
96
  hb_free (data);
97
}
98

99
/* Constants for algorithmic hangul syllable [de]composition. */
100
#define LBase 0x1100u
101
#define VBase 0x1161u
102
#define TBase 0x11A7u
103
#define LCount 19u
104
#define VCount 21u
105
#define TCount 28u
106
#define SBase 0xAC00u
107
#define NCount (VCount * TCount)
108
#define SCount (LCount * NCount)
109

110
#define isCombiningL(u) (hb_in_range<hb_codepoint_t> ((u), LBase, LBase+LCount-1))
111
#define isCombiningV(u) (hb_in_range<hb_codepoint_t> ((u), VBase, VBase+VCount-1))
112
#define isCombiningT(u) (hb_in_range<hb_codepoint_t> ((u), TBase+1, TBase+TCount-1))
113
#define isCombinedS(u) (hb_in_range<hb_codepoint_t> ((u), SBase, SBase+SCount-1))
114

115
#define isL(u) (hb_in_ranges<hb_codepoint_t> ((u), 0x1100u, 0x115Fu, 0xA960u, 0xA97Cu))
116
#define isV(u) (hb_in_ranges<hb_codepoint_t> ((u), 0x1160u, 0x11A7u, 0xD7B0u, 0xD7C6u))
117
#define isT(u) (hb_in_ranges<hb_codepoint_t> ((u), 0x11A8u, 0x11FFu, 0xD7CBu, 0xD7FBu))
118

119
#define isHangulTone(u) (hb_in_range<hb_codepoint_t> ((u), 0x302Eu, 0x302Fu))
120

121
/* buffer var allocations */
122
#define hangul_shaping_feature() ot_shaper_var_u8_auxiliary() /* hangul jamo shaping feature */
123

124
static bool
125
is_zero_width_char (hb_font_t *font,
126
                    hb_codepoint_t unicode)
127
{
128
  hb_codepoint_t glyph;
129
  return hb_font_get_glyph (font, unicode, 0, &glyph) && hb_font_get_glyph_h_advance (font, glyph) == 0;
130
}
131

132
static void
133
preprocess_text_hangul (const hb_ot_shape_plan_t *plan HB_UNUSED,
134
                        hb_buffer_t              *buffer,
135
                        hb_font_t                *font)
136
{
137
  HB_BUFFER_ALLOCATE_VAR (buffer, hangul_shaping_feature);
138

139
  /* Hangul syllables come in two shapes: LV, and LVT.  Of those:
140
   *
141
   *   - LV can be precomposed, or decomposed.  Lets call those
142
   *     <LV> and <L,V>,
143
   *   - LVT can be fully precomposed, partially precomposed, or
144
   *     fully decomposed.  Ie. <LVT>, <LV,T>, or <L,V,T>.
145
   *
146
   * The composition / decomposition is mechanical.  However, not
147
   * all <L,V> sequences compose, and not all <LV,T> sequences
148
   * compose.
149
   *
150
   * Here are the specifics:
151
   *
152
   *   - <L>: U+1100..115F, U+A960..A97F
153
   *   - <V>: U+1160..11A7, U+D7B0..D7C7
154
   *   - <T>: U+11A8..11FF, U+D7CB..D7FB
155
   *
156
   *   - Only the <L,V> sequences for some of the U+11xx ranges combine.
157
   *   - Only <LV,T> sequences for some of the Ts in U+11xx range combine.
158
   *
159
   * Here is what we want to accomplish in this shaper:
160
   *
161
   *   - If the whole syllable can be precomposed, do that,
162
   *   - Otherwise, fully decompose and apply ljmo/vjmo/tjmo features.
163
   *   - If a valid syllable is followed by a Hangul tone mark, reorder the tone
164
   *     mark to precede the whole syllable - unless it is a zero-width glyph, in
165
   *     which case we leave it untouched, assuming it's designed to overstrike.
166
   *
167
   * That is, of the different possible syllables:
168
   *
169
   *   <L>
170
   *   <L,V>
171
   *   <L,V,T>
172
   *   <LV>
173
   *   <LVT>
174
   *   <LV, T>
175
   *
176
   * - <L> needs no work.
177
   *
178
   * - <LV> and <LVT> can stay the way they are if the font supports them, otherwise we
179
   *   should fully decompose them if font supports.
180
   *
181
   * - <L,V> and <L,V,T> we should compose if the whole thing can be composed.
182
   *
183
   * - <LV,T> we should compose if the whole thing can be composed, otherwise we should
184
   *   decompose.
185
   */
186

187
  buffer->clear_output ();
188
  unsigned int start = 0, end = 0; /* Extent of most recently seen syllable;
189
                                    * valid only if start < end
190
                                    */
191
  unsigned int count = buffer->len;
192

193
  for (buffer->idx = 0; buffer->idx < count && buffer->successful;)
194
  {
195
    hb_codepoint_t u = buffer->cur().codepoint;
196

197
    if (isHangulTone (u))
198
    {
199
      /*
200
       * We could cache the width of the tone marks and the existence of dotted-circle,
201
       * but the use of the Hangul tone mark characters seems to be rare enough that
202
       * I didn't bother for now.
203
       */
204
      if (start < end && end == buffer->out_len)
205
      {
206
        /* Tone mark follows a valid syllable; move it in front, unless it's zero width. */
207
        buffer->unsafe_to_break_from_outbuffer (start, buffer->idx);
208
        if (unlikely (!buffer->next_glyph ())) break;
209
        if (!is_zero_width_char (font, u))
210
        {
211
          buffer->merge_out_clusters (start, end + 1);
212
          hb_glyph_info_t *info = buffer->out_info;
213
          hb_glyph_info_t tone = info[end];
214
          memmove (&info[start + 1], &info[start], (end - start) * sizeof (hb_glyph_info_t));
215
          info[start] = tone;
216
        }
217
      }
218
      else
219
      {
220
        /* No valid syllable as base for tone mark; try to insert dotted circle. */
221
        if (!(buffer->flags & HB_BUFFER_FLAG_DO_NOT_INSERT_DOTTED_CIRCLE) &&
222
            font->has_glyph (0x25CCu))
223
        {
224
          hb_codepoint_t chars[2];
225
          if (!is_zero_width_char (font, u))
226
          {
227
            chars[0] = u;
228
            chars[1] = 0x25CCu;
229
          } else
230
          {
231
            chars[0] = 0x25CCu;
232
            chars[1] = u;
233
          }
234
          (void) buffer->replace_glyphs (1, 2, chars);
235
        }
236
        else
237
        {
238
          /* No dotted circle available in the font; just leave tone mark untouched. */
239
          (void) buffer->next_glyph ();
240
        }
241
      }
242
      start = end = buffer->out_len;
243
      continue;
244
    }
245

246
    start = buffer->out_len; /* Remember current position as a potential syllable start;
247
                              * will only be used if we set end to a later position.
248
                              */
249

250
    if (isL (u) && buffer->idx + 1 < count)
251
    {
252
      hb_codepoint_t l = u;
253
      hb_codepoint_t v = buffer->cur(+1).codepoint;
254
      if (isV (v))
255
      {
256
        /* Have <L,V> or <L,V,T>. */
257
        hb_codepoint_t t = 0;
258
        unsigned int tindex = 0;
259
        if (buffer->idx + 2 < count)
260
        {
261
          t = buffer->cur(+2).codepoint;
262
          if (isT (t))
263
            tindex = t - TBase; /* Only used if isCombiningT (t); otherwise invalid. */
264
          else
265
            t = 0; /* The next character was not a trailing jamo. */
266
        }
267
        buffer->unsafe_to_break (buffer->idx, buffer->idx + (t ? 3 : 2));
268

269
        /* We've got a syllable <L,V,T?>; see if it can potentially be composed. */
270
        if (isCombiningL (l) && isCombiningV (v) && (t == 0 || isCombiningT (t)))
271
        {
272
          /* Try to compose; if this succeeds, end is set to start+1. */
273
          hb_codepoint_t s = SBase + (l - LBase) * NCount + (v - VBase) * TCount + tindex;
274
          if (font->has_glyph (s))
275
          {
276
            (void) buffer->replace_glyphs (t ? 3 : 2, 1, &s);
277
            end = start + 1;
278
            continue;
279
          }
280
        }
281

282
        /* We didn't compose, either because it's an Old Hangul syllable without a
283
         * precomposed character in Unicode, or because the font didn't support the
284
         * necessary precomposed glyph.
285
         * Set jamo features on the individual glyphs, and advance past them.
286
         */
287
        buffer->cur().hangul_shaping_feature() = LJMO;
288
        (void) buffer->next_glyph ();
289
        buffer->cur().hangul_shaping_feature() = VJMO;
290
        (void) buffer->next_glyph ();
291
        if (t)
292
        {
293
          buffer->cur().hangul_shaping_feature() = TJMO;
294
          (void) buffer->next_glyph ();
295
          end = start + 3;
296
        }
297
        else
298
          end = start + 2;
299
        if (unlikely (!buffer->successful))
300
          break;
301
        if (buffer->cluster_level == HB_BUFFER_CLUSTER_LEVEL_MONOTONE_GRAPHEMES)
302
          buffer->merge_out_clusters (start, end);
303
        continue;
304
      }
305
    }
306

307
    else if (isCombinedS (u))
308
    {
309
      /* Have <LV>, <LVT>, or <LV,T> */
310
      hb_codepoint_t s = u;
311
      bool has_glyph = font->has_glyph (s);
312
      unsigned int lindex = (s - SBase) / NCount;
313
      unsigned int nindex = (s - SBase) % NCount;
314
      unsigned int vindex = nindex / TCount;
315
      unsigned int tindex = nindex % TCount;
316

317
      if (!tindex &&
318
          buffer->idx + 1 < count &&
319
          isCombiningT (buffer->cur(+1).codepoint))
320
      {
321
        /* <LV,T>, try to combine. */
322
        unsigned int new_tindex = buffer->cur(+1).codepoint - TBase;
323
        hb_codepoint_t new_s = s + new_tindex;
324
        if (font->has_glyph (new_s))
325
        {
326
          (void) buffer->replace_glyphs (2, 1, &new_s);
327
          end = start + 1;
328
          continue;
329
        }
330
        else
331
          buffer->unsafe_to_break (buffer->idx, buffer->idx + 2); /* Mark unsafe between LV and T. */
332
      }
333

334
      /* Otherwise, decompose if font doesn't support <LV> or <LVT>,
335
       * or if having non-combining <LV,T>.  Note that we already handled
336
       * combining <LV,T> above. */
337
      if (!has_glyph ||
338
          (!tindex &&
339
           buffer->idx + 1 < count &&
340
           isT (buffer->cur(+1).codepoint)))
341
      {
342
        hb_codepoint_t decomposed[3] = {LBase + lindex,
343
                                        VBase + vindex,
344
                                        TBase + tindex};
345
        if (font->has_glyph (decomposed[0]) &&
346
            font->has_glyph (decomposed[1]) &&
347
            (!tindex || font->has_glyph (decomposed[2])))
348
        {
349
          unsigned int s_len = tindex ? 3 : 2;
350
          (void) buffer->replace_glyphs (1, s_len, decomposed);
351

352
          /* If we decomposed an LV because of a non-combining T following,
353
           * we want to include this T in the syllable.
354
           */
355
          if (has_glyph && !tindex)
356
          {
357
            (void) buffer->next_glyph ();
358
            s_len++;
359
          }
360
          if (unlikely (!buffer->successful))
361
            break;
362

363
          /* We decomposed S: apply jamo features to the individual glyphs
364
           * that are now in buffer->out_info.
365
           */
366
          hb_glyph_info_t *info = buffer->out_info;
367
          end = start + s_len;
368

369
          unsigned int i = start;
370
          info[i++].hangul_shaping_feature() = LJMO;
371
          info[i++].hangul_shaping_feature() = VJMO;
372
          if (i < end)
373
            info[i++].hangul_shaping_feature() = TJMO;
374

375
          if (buffer->cluster_level == HB_BUFFER_CLUSTER_LEVEL_MONOTONE_GRAPHEMES)
376
            buffer->merge_out_clusters (start, end);
377
          continue;
378
        }
379
        else if ((!tindex && buffer->idx + 1 < count && isT (buffer->cur(+1).codepoint)))
380
          buffer->unsafe_to_break (buffer->idx, buffer->idx + 2); /* Mark unsafe between LV and T. */
381
      }
382

383
      if (has_glyph)
384
      {
385
        /* We didn't decompose the S, so just advance past it and fall through. */
386
        end = start + 1;
387
      }
388
    }
389

390
    /* Didn't find a recognizable syllable, so we leave end <= start;
391
     * this will prevent tone-mark reordering happening.
392
     */
393
    (void) buffer->next_glyph ();
394
  }
395
  buffer->sync ();
396
}
397

398
static void
399
setup_masks_hangul (const hb_ot_shape_plan_t *plan,
400
                    hb_buffer_t              *buffer,
401
                    hb_font_t                *font HB_UNUSED)
402
{
403
  const hangul_shape_plan_t *hangul_plan = (const hangul_shape_plan_t *) plan->data;
404

405
  if (likely (hangul_plan))
406
  {
407
    unsigned int count = buffer->len;
408
    hb_glyph_info_t *info = buffer->info;
409
    for (unsigned int i = 0; i < count; i++, info++)
410
      info->mask |= hangul_plan->mask_array[info->hangul_shaping_feature()];
411
  }
412

413
  HB_BUFFER_DEALLOCATE_VAR (buffer, hangul_shaping_feature);
414
}
415

416

417
const hb_ot_shaper_t _hb_ot_shaper_hangul =
418
{
419
  collect_features_hangul,
420
  override_features_hangul,
421
  data_create_hangul,
422
  data_destroy_hangul,
423
  preprocess_text_hangul,
424
  nullptr, /* postprocess_glyphs */
425
  nullptr, /* decompose */
426
  nullptr, /* compose */
427
  setup_masks_hangul,
428
  nullptr, /* reorder_marks */
429
  HB_TAG_NONE, /* gpos_tag */
430
  HB_OT_SHAPE_NORMALIZATION_MODE_NONE,
431
  HB_OT_SHAPE_ZERO_WIDTH_MARKS_NONE,
432
  false, /* fallback_position */
433
};
434

435

436
#endif
437

Использование cookies

Мы используем файлы cookie в соответствии с Политикой конфиденциальности и Политикой использования cookies.

Нажимая кнопку «Принимаю», Вы даете АО «СберТех» согласие на обработку Ваших персональных данных в целях совершенствования нашего веб-сайта и Сервиса GitVerse, а также повышения удобства их использования.

Запретить использование cookies Вы можете самостоятельно в настройках Вашего браузера.