third_party/harfbuzz-ng/src/hb-graphite2.cc

   1 /*
   2  * Copyright © 2011  Martin Hosken
   3  * Copyright © 2011  SIL International
   4  * Copyright © 2011,2012  Google, Inc.
   5  *
   6  *  This is part of HarfBuzz, a text shaping library.
   7  *
   8  * Permission is hereby granted, without written agreement and without
   9  * license or royalty fees, to use, copy, modify, and distribute this
  10  * software and its documentation for any purpose, provided that the
  11  * above copyright notice and the following two paragraphs appear in
  12  * all copies of this software.
  13  *
  14  * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
  15  * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
  16  * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
  17  * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
  18  * DAMAGE.
  19  *
  20  * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
  21  * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
  22  * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
  23  * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
  24  * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
  25  *
  26  * Google Author(s): Behdad Esfahbod
  27  */
  28
  29 #define HB_SHAPER graphite2
  30 #define hb_graphite2_shaper_font_data_t gr_font
  31 #include "hb-shaper-impl-private.hh"
  32
  33 #include <graphite2/Font.h>
  34 #include <graphite2/Segment.h>
  35
  36 #include "hb-graphite2.h"
  37
  38 #include "hb-ot-tag.h"
  39
  40
  41 HB_SHAPER_DATA_ENSURE_DECLARE(graphite2, face)
  42 HB_SHAPER_DATA_ENSURE_DECLARE(graphite2, font)
  43
  44
  45 /*
  46  * shaper face data
  47  */
  48
  49 typedef struct hb_graphite2_tablelist_t {
  50   struct hb_graphite2_tablelist_t *next;
  51   hb_blob_t *blob;
  52   unsigned int tag;
  53 } hb_graphite2_tablelist_t;
  54
  55 struct hb_graphite2_shaper_face_data_t {
  56   hb_face_t *face;
  57   gr_face   *grface;
  58   hb_graphite2_tablelist_t *tlist;
  59 };
  60
  61 static const void *hb_graphite2_get_table (const void *data, unsigned int tag, size_t *len)
  62 {
  63   hb_graphite2_shaper_face_data_t *face_data = (hb_graphite2_shaper_face_data_t *) data;
  64   hb_graphite2_tablelist_t *tlist = face_data->tlist;
  65
  66   hb_blob_t *blob = NULL;
  67
  68   for (hb_graphite2_tablelist_t *p = tlist; p; p = p->next)
  69     if (p->tag == tag) {
  70       blob = p->blob;
  71       break;
  72     }
  73
  74   if (unlikely (!blob))
  75   {
  76     blob = face_data->face->reference_table (tag);
  77
  78     hb_graphite2_tablelist_t *p = (hb_graphite2_tablelist_t *) calloc (1, sizeof (hb_graphite2_tablelist_t));
  79     if (unlikely (!p)) {
  80       hb_blob_destroy (blob);
  81       return NULL;
  82     }
  83     p->blob = blob;
  84     p->tag = tag;
  85
  86     /* TODO Not thread-safe, but fairly harmless.
  87      * We can do the double-chcked pointer cmpexch thing here. */
  88     p->next = face_data->tlist;
  89     face_data->tlist = p;
  90   }
  91
  92   unsigned int tlen;
  93   const char *d = hb_blob_get_data (blob, &tlen);
  94   *len = tlen;
  95   return d;
  96 }
  97
  98 hb_graphite2_shaper_face_data_t *
  99 _hb_graphite2_shaper_face_data_create (hb_face_t *face)
 100 {
 101   hb_blob_t *silf_blob = face->reference_table (HB_GRAPHITE2_TAG_SILF);
 102   /* Umm, we just reference the table to check whether it exists.
 103    * Maybe add better API for this? */
 104   if (!hb_blob_get_length (silf_blob))
 105   {
 106     hb_blob_destroy (silf_blob);
 107     return NULL;
 108   }
 109   hb_blob_destroy (silf_blob);
 110
 111   hb_graphite2_shaper_face_data_t *data = (hb_graphite2_shaper_face_data_t *) calloc (1, sizeof (hb_graphite2_shaper_face_data_t));
 112   if (unlikely (!data))
 113     hb_blob_destroy (silf_blob);
 114
 115   data->face = face;
 116   data->grface = gr_make_face (data, &hb_graphite2_get_table, gr_face_default);
 117
 118   if (unlikely (!data->grface)) {
 119     free (data);
 120     return NULL;
 121   }
 122
 123   return data;
 124 }
 125
 126 void
 127 _hb_graphite2_shaper_face_data_destroy (hb_graphite2_shaper_face_data_t *data)
 128 {
 129   hb_graphite2_tablelist_t *tlist = data->tlist;
 130
 131   while (tlist)
 132   {
 133     hb_graphite2_tablelist_t *old = tlist;
 134     hb_blob_destroy (tlist->blob);
 135     tlist = tlist->next;
 136     free (old);
 137   }
 138
 139   gr_face_destroy (data->grface);
 140
 141   free (data);
 142 }
 143
 144
 145 /*
 146  * shaper font data
 147  */
 148
 149 static float hb_graphite2_get_advance (const void *hb_font, unsigned short gid)
 150 {
 151   return ((hb_font_t *) hb_font)->get_glyph_h_advance (gid);
 152 }
 153
 154 hb_graphite2_shaper_font_data_t *
 155 _hb_graphite2_shaper_font_data_create (hb_font_t *font)
 156 {
 157   if (unlikely (!hb_graphite2_shaper_face_data_ensure (font->face))) return NULL;
 158
 159   hb_face_t *face = font->face;
 160   hb_graphite2_shaper_face_data_t *face_data = HB_SHAPER_DATA_GET (face);
 161
 162   return gr_make_font_with_advance_fn (font->x_scale, font, &hb_graphite2_get_advance, face_data->grface);
 163 }
 164
 165 void
 166 _hb_graphite2_shaper_font_data_destroy (hb_graphite2_shaper_font_data_t *data)
 167 {
 168   gr_font_destroy (data);
 169 }
 170
 171
 172 /*
 173  * shaper shape_plan data
 174  */
 175
 176 struct hb_graphite2_shaper_shape_plan_data_t {};
 177
 178 hb_graphite2_shaper_shape_plan_data_t *
 179 _hb_graphite2_shaper_shape_plan_data_create (hb_shape_plan_t    *shape_plan HB_UNUSED,
 180                                              const hb_feature_t *user_features HB_UNUSED,
 181                                              unsigned int        num_user_features HB_UNUSED)
 182 {
 183   return (hb_graphite2_shaper_shape_plan_data_t *) HB_SHAPER_DATA_SUCCEEDED;
 184 }
 185
 186 void
 187 _hb_graphite2_shaper_shape_plan_data_destroy (hb_graphite2_shaper_shape_plan_data_t *data HB_UNUSED)
 188 {
 189 }
 190
 191
 192 /*
 193  * shaper
 194  */
 195
 196 struct hb_graphite2_cluster_t {
 197   unsigned int base_char;
 198   unsigned int num_chars;
 199   unsigned int base_glyph;
 200   unsigned int num_glyphs;
 201 };
 202
 203 hb_bool_t
 204 _hb_graphite2_shape (hb_shape_plan_t    *shape_plan,
 205                      hb_font_t          *font,
 206                      hb_buffer_t        *buffer,
 207                      const hb_feature_t *features,
 208                      unsigned int        num_features)
 209 {
 210   hb_face_t *face = font->face;
 211   gr_face *grface = HB_SHAPER_DATA_GET (face)->grface;
 212   gr_font *grfont = HB_SHAPER_DATA_GET (font);
 213
 214   const char *lang = hb_language_to_string (hb_buffer_get_language (buffer));
 215   const char *lang_end = strchr (lang, '-');
 216   int lang_len = lang_end ? lang_end - lang : -1;
 217   gr_feature_val *feats = gr_face_featureval_for_lang (grface, lang ? hb_tag_from_string (lang, lang_len) : 0);
 218
 219   while (num_features--)
 220   {
 221     const gr_feature_ref *fref = gr_face_find_fref (grface, features->tag);
 222     if (fref)
 223       gr_fref_set_feature_value (fref, features->value, feats);
 224     features++;
 225   }
 226
 227   gr_segment *seg = NULL;
 228   const gr_slot *is;
 229   unsigned int ci = 0, ic = 0;
 230   float curradvx = 0., curradvy = 0.;
 231
 232   unsigned int scratch_size;
 233   char *scratch = (char *) buffer->get_scratch_buffer (&scratch_size);
 234
 235 #define ALLOCATE_ARRAY(Type, name, len) \
 236   Type *name = (Type *) scratch; \
 237   scratch += (len) * sizeof ((name)[0]); \
 238   scratch_size -= (len) * sizeof ((name)[0]);
 239
 240   ALLOCATE_ARRAY (uint32_t, chars, buffer->len);
 241
 242   for (unsigned int i = 0; i < buffer->len; ++i)
 243     chars[i] = buffer->info[i].codepoint;
 244
 245   hb_tag_t script_tag[2];
 246   hb_ot_tags_from_script (hb_buffer_get_script (buffer), &script_tag[0], &script_tag[1]);
 247
 248   seg = gr_make_seg (grfont, grface,
 249                      script_tag[1] == HB_TAG_NONE ? script_tag[0] : script_tag[1],
 250                      feats,
 251                      gr_utf32, chars, buffer->len,
 252                      2 | (hb_buffer_get_direction (buffer) == HB_DIRECTION_RTL ? 1 : 0));
 253
 254   if (unlikely (!seg)) {
 255     if (feats) gr_featureval_destroy (feats);
 256     return false;
 257   }
 258
 259   unsigned int glyph_count = gr_seg_n_slots (seg);
 260   if (unlikely (!glyph_count)) {
 261     if (feats) gr_featureval_destroy (feats);
 262     gr_seg_destroy (seg);
 263     return false;
 264   }
 265
 266   scratch = (char *) buffer->get_scratch_buffer (&scratch_size);
 267   while ((sizeof (hb_graphite2_cluster_t) * buffer->len +
 268           sizeof (hb_codepoint_t) * glyph_count) > scratch_size)
 269   {
 270     buffer->ensure (buffer->allocated * 2);
 271     if (unlikely (buffer->in_error)) {
 272       if (feats) gr_featureval_destroy (feats);
 273       gr_seg_destroy (seg);
 274       return false;
 275     }
 276     scratch = (char *) buffer->get_scratch_buffer (&scratch_size);
 277   }
 278
 279   ALLOCATE_ARRAY (hb_graphite2_cluster_t, clusters, buffer->len);
 280   ALLOCATE_ARRAY (hb_codepoint_t, gids, glyph_count);
 281
 282   memset (clusters, 0, sizeof (clusters[0]) * buffer->len);
 283
 284   hb_codepoint_t *pg = gids;
 285   for (is = gr_seg_first_slot (seg), ic = 0; is; is = gr_slot_next_in_segment (is), ic++)
 286   {
 287     unsigned int before = gr_slot_before (is);
 288     unsigned int after = gr_slot_after (is);
 289     *pg = gr_slot_gid (is);
 290     pg++;
 291     while (clusters[ci].base_char > before && ci)
 292     {
 293       clusters[ci-1].num_chars += clusters[ci].num_chars;
 294       clusters[ci-1].num_glyphs += clusters[ci].num_glyphs;
 295       ci--;
 296     }
 297
 298     if (gr_slot_can_insert_before (is) && clusters[ci].num_chars && before >= clusters[ci].base_char + clusters[ci].num_chars)
 299     {
 300       hb_graphite2_cluster_t *c = clusters + ci + 1;
 301       c->base_char = clusters[ci].base_char + clusters[ci].num_chars;
 302       c->num_chars = before - c->base_char;
 303       c->base_glyph = ic;
 304       c->num_glyphs = 0;
 305       ci++;
 306     }
 307     clusters[ci].num_glyphs++;
 308
 309     if (clusters[ci].base_char + clusters[ci].num_chars < after + 1)
 310         clusters[ci].num_chars = after + 1 - clusters[ci].base_char;
 311   }
 312   ci++;
 313
 314   buffer->clear_output ();
 315   for (unsigned int i = 0; i < ci; ++i)
 316     buffer->replace_glyphs (clusters[i].num_chars, clusters[i].num_glyphs, gids + clusters[i].base_glyph);
 317   buffer->swap_buffers ();
 318
 319   if (HB_DIRECTION_IS_BACKWARD(buffer->props.direction))
 320     curradvx = gr_seg_advance_X(seg);
 321
 322   hb_glyph_position_t *pPos;
 323   for (pPos = hb_buffer_get_glyph_positions (buffer, NULL), is = gr_seg_first_slot (seg);
 324        is; pPos++, is = gr_slot_next_in_segment (is))
 325   {
 326     pPos->x_offset = gr_slot_origin_X (is) - curradvx;
 327     pPos->y_offset = gr_slot_origin_Y (is) - curradvy;
 328     pPos->x_advance = gr_slot_advance_X (is, grface, grfont);
 329     pPos->y_advance = gr_slot_advance_Y (is, grface, grfont);
 330     if (HB_DIRECTION_IS_BACKWARD (buffer->props.direction))
 331       curradvx -= pPos->x_advance;
 332     pPos->x_offset = gr_slot_origin_X (is) - curradvx;
 333     if (!HB_DIRECTION_IS_BACKWARD (buffer->props.direction))
 334       curradvx += pPos->x_advance;
 335     pPos->y_offset = gr_slot_origin_Y (is) - curradvy;
 336     curradvy += pPos->y_advance;
 337   }
 338   if (!HB_DIRECTION_IS_BACKWARD (buffer->props.direction))
 339     pPos[-1].x_advance += gr_seg_advance_X(seg) - curradvx;
 340
 341   if (HB_DIRECTION_IS_BACKWARD (buffer->props.direction))
 342     hb_buffer_reverse_clusters (buffer);
 343
 344   if (feats) gr_featureval_destroy (feats);
 345   gr_seg_destroy (seg);
 346
 347   return true;
 348 }