src/hb-subset-plan.cc

   1 /*
   2  * Copyright © 2018  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): Garret Rieger, Roderick Sheeter
  25  */
  26
  27 #include "hb-subset-plan.hh"
  28 #include "hb-map.hh"
  29 #include "hb-set.hh"
  30
  31 #include "hb-ot-cmap-table.hh"
  32 #include "hb-ot-glyf-table.hh"
  33 #include "hb-ot-layout-gdef-table.hh"
  34 #include "hb-ot-layout-gpos-table.hh"
  35 #include "hb-ot-cff1-table.hh"
  36 #include "hb-ot-color-colr-table.hh"
  37 #include "hb-ot-var-fvar-table.hh"
  38 #include "hb-ot-stat-table.hh"
  39
  40
  41 #ifndef HB_NO_SUBSET_CFF
  42 static inline void
  43 _add_cff_seac_components (const OT::cff1::accelerator_t &cff,
  44                           hb_codepoint_t gid,
  45                           hb_set_t *gids_to_retain)
  46 {
  47   hb_codepoint_t base_gid, accent_gid;
  48   if (cff.get_seac_components (gid, &base_gid, &accent_gid))
  49   {
  50     gids_to_retain->add (base_gid);
  51     gids_to_retain->add (accent_gid);
  52   }
  53 }
  54 #endif
  55
  56 #ifndef HB_NO_SUBSET_LAYOUT
  57 #ifdef HB_EXPERIMENTAL_API
  58 static void
  59 _remap_indexes (const hb_set_t *indexes,
  60                 hb_map_t       *mapping /* OUT */)
  61 {
  62   unsigned count = indexes->get_population ();
  63
  64   for (auto _ : + hb_zip (indexes->iter (), hb_range (count)))
  65     mapping->set (_.first, _.second);
  66
  67 }
  68 #endif
  69
  70 static inline void
  71 _gsub_closure_glyphs_lookups_features (hb_face_t *face,
  72                                        hb_set_t *gids_to_retain,
  73                                        hb_map_t *gsub_lookups,
  74                                        hb_map_t *gsub_features)
  75 {
  76   hb_set_t lookup_indices;
  77   hb_ot_layout_collect_lookups (face,
  78                                 HB_OT_TAG_GSUB,
  79                                 nullptr,
  80                                 nullptr,
  81                                 nullptr,
  82                                 &lookup_indices);
  83   hb_ot_layout_lookups_substitute_closure (face,
  84                                            &lookup_indices,
  85                                            gids_to_retain);
  86 #ifdef HB_EXPERIMENTAL_API
  87   hb_ot_layout_closure_lookups (face,
  88                                 HB_OT_TAG_GSUB,
  89                                 gids_to_retain,
  90                                 &lookup_indices);
  91   _remap_indexes (&lookup_indices, gsub_lookups);
  92
  93   //closure features
  94   hb_set_t feature_indices;
  95   hb_ot_layout_closure_features (face,
  96                                  HB_OT_TAG_GSUB,
  97                                  gsub_lookups,
  98                                  &feature_indices);
  99   _remap_indexes (&feature_indices, gsub_features);
 100 #endif
 101 }
 102
 103 static inline void
 104 _gpos_closure_lookups_features (hb_face_t      *face,
 105                                 const hb_set_t *gids_to_retain,
 106                                 hb_map_t       *gpos_lookups,
 107                                 hb_map_t       *gpos_features)
 108 {
 109   hb_set_t lookup_indices;
 110   hb_ot_layout_collect_lookups (face,
 111                                 HB_OT_TAG_GPOS,
 112                                 nullptr,
 113                                 nullptr,
 114                                 nullptr,
 115                                 &lookup_indices);
 116 #ifdef HB_EXPERIMENTAL_API
 117   hb_ot_layout_closure_lookups (face,
 118                                 HB_OT_TAG_GPOS,
 119                                 gids_to_retain,
 120                                 &lookup_indices);
 121   _remap_indexes (&lookup_indices, gpos_lookups);
 122
 123   //closure features
 124   hb_set_t feature_indices;
 125   hb_ot_layout_closure_features (face,
 126                                  HB_OT_TAG_GPOS,
 127                                  gpos_lookups,
 128                                  &feature_indices);
 129   _remap_indexes (&feature_indices, gpos_features);
 130 #endif
 131 }
 132 #endif
 133
 134 #ifndef HB_NO_VAR
 135 static inline void
 136   _collect_layout_variation_indices (hb_face_t *face,
 137                                      const hb_set_t *glyphset,
 138                                      const hb_map_t *gpos_lookups,
 139                                      hb_set_t  *layout_variation_indices,
 140                                      hb_map_t  *layout_variation_idx_map)
 141 {
 142   hb_blob_ptr_t<OT::GDEF> gdef = hb_sanitize_context_t ().reference_table<OT::GDEF> (face);
 143   hb_blob_ptr_t<OT::GPOS> gpos = hb_sanitize_context_t ().reference_table<OT::GPOS> (face);
 144
 145   if (!gdef->has_data ())
 146   {
 147     gdef.destroy ();
 148     gpos.destroy ();
 149     return;
 150   }
 151   OT::hb_collect_variation_indices_context_t c (layout_variation_indices, glyphset, gpos_lookups);
 152   gdef->collect_variation_indices (&c);
 153
 154   if (hb_ot_layout_has_positioning (face))
 155     gpos->collect_variation_indices (&c);
 156
 157   gdef->remap_layout_variation_indices (layout_variation_indices, layout_variation_idx_map);
 158
 159   gdef.destroy ();
 160   gpos.destroy ();
 161 }
 162 #endif
 163
 164 static inline void
 165 _cmap_closure (hb_face_t           *face,
 166                const hb_set_t      *unicodes,
 167                hb_set_t            *glyphset)
 168 {
 169   OT::cmap::accelerator_t cmap;
 170   cmap.init (face);
 171   cmap.table->closure_glyphs (unicodes, glyphset);
 172   cmap.fini ();
 173 }
 174
 175 static inline void
 176 _remove_invalid_gids (hb_set_t *glyphs,
 177                       unsigned int num_glyphs)
 178 {
 179   hb_codepoint_t gid = HB_SET_VALUE_INVALID;
 180   while (glyphs->next (&gid))
 181   {
 182     if (gid >= num_glyphs)
 183       glyphs->del (gid);
 184   }
 185 }
 186
 187 static void
 188 _populate_gids_to_retain (hb_subset_plan_t* plan,
 189                           const hb_set_t *unicodes,
 190                           const hb_set_t *input_glyphs_to_retain,
 191                           bool close_over_gsub,
 192                           bool close_over_gpos,
 193                           bool close_over_gdef)
 194 {
 195   OT::cmap::accelerator_t cmap;
 196   OT::glyf::accelerator_t glyf;
 197 #ifndef HB_NO_SUBSET_CFF
 198   OT::cff1::accelerator_t cff;
 199 #endif
 200   OT::COLR::accelerator_t colr;
 201   cmap.init (plan->source);
 202   glyf.init (plan->source);
 203 #ifndef HB_NO_SUBSET_CFF
 204   cff.init (plan->source);
 205 #endif
 206   colr.init (plan->source);
 207
 208   plan->_glyphset_gsub->add (0); // Not-def
 209   hb_set_union (plan->_glyphset_gsub, input_glyphs_to_retain);
 210
 211   hb_codepoint_t cp = HB_SET_VALUE_INVALID;
 212   while (unicodes->next (&cp))
 213   {
 214     hb_codepoint_t gid;
 215     if (!cmap.get_nominal_glyph (cp, &gid))
 216     {
 217       DEBUG_MSG(SUBSET, nullptr, "Drop U+%04X; no gid", cp);
 218       continue;
 219     }
 220     plan->unicodes->add (cp);
 221     plan->codepoint_to_glyph->set (cp, gid);
 222     plan->_glyphset_gsub->add (gid);
 223   }
 224
 225   _cmap_closure (plan->source, plan->unicodes, plan->_glyphset_gsub);
 226
 227 #ifndef HB_NO_SUBSET_LAYOUT
 228   if (close_over_gsub)
 229     // closure all glyphs/lookups/features needed for GSUB substitutions.
 230     _gsub_closure_glyphs_lookups_features (plan->source, plan->_glyphset_gsub, plan->gsub_lookups, plan->gsub_features);
 231
 232   if (close_over_gpos)
 233     _gpos_closure_lookups_features (plan->source, plan->_glyphset_gsub, plan->gpos_lookups, plan->gpos_features);
 234 #endif
 235   _remove_invalid_gids (plan->_glyphset_gsub, plan->source->get_num_glyphs ());
 236
 237   // Populate a full set of glyphs to retain by adding all referenced
 238   // composite glyphs.
 239   hb_codepoint_t gid = HB_SET_VALUE_INVALID;
 240   while (plan->_glyphset_gsub->next (&gid))
 241   {
 242     glyf.add_gid_and_children (gid, plan->_glyphset);
 243 #ifndef HB_NO_SUBSET_CFF
 244     if (cff.is_valid ())
 245       _add_cff_seac_components (cff, gid, plan->_glyphset);
 246 #endif
 247     if (colr.is_valid ())
 248       colr.closure_glyphs (gid, plan->_glyphset);
 249   }
 250
 251   _remove_invalid_gids (plan->_glyphset, plan->source->get_num_glyphs ());
 252
 253 #ifndef HB_NO_VAR
 254   if (close_over_gdef)
 255     _collect_layout_variation_indices (plan->source, plan->_glyphset, plan->gpos_lookups, plan->layout_variation_indices, plan->layout_variation_idx_map);
 256 #endif
 257
 258 #ifndef HB_NO_SUBSET_CFF
 259   cff.fini ();
 260 #endif
 261   glyf.fini ();
 262   cmap.fini ();
 263 }
 264
 265 static void
 266 _create_old_gid_to_new_gid_map (const hb_face_t *face,
 267                                 bool             retain_gids,
 268                                 const hb_set_t  *all_gids_to_retain,
 269                                 hb_map_t        *glyph_map, /* OUT */
 270                                 hb_map_t        *reverse_glyph_map, /* OUT */
 271                                 unsigned int    *num_glyphs /* OUT */)
 272 {
 273   if (!retain_gids)
 274   {
 275     + hb_enumerate (hb_iter (all_gids_to_retain), (hb_codepoint_t) 0)
 276     | hb_sink (reverse_glyph_map)
 277     ;
 278     *num_glyphs = reverse_glyph_map->get_population ();
 279   } else {
 280     + hb_iter (all_gids_to_retain)
 281     | hb_map ([] (hb_codepoint_t _) {
 282                 return hb_pair_t<hb_codepoint_t, hb_codepoint_t> (_, _);
 283               })
 284     | hb_sink (reverse_glyph_map)
 285     ;
 286
 287     unsigned max_glyph =
 288     + hb_iter (all_gids_to_retain)
 289     | hb_reduce (hb_max, 0u)
 290     ;
 291     *num_glyphs = max_glyph + 1;
 292   }
 293
 294   + reverse_glyph_map->iter ()
 295   | hb_map (&hb_pair_t<hb_codepoint_t, hb_codepoint_t>::reverse)
 296   | hb_sink (glyph_map)
 297   ;
 298 }
 299
 300 static void
 301 _nameid_closure (hb_face_t *face,
 302                  hb_set_t  *nameids)
 303 {
 304 #ifndef HB_NO_STAT
 305   face->table.STAT->collect_name_ids (nameids);
 306 #endif
 307 #ifndef HB_NO_VAR
 308   face->table.fvar->collect_name_ids (nameids);
 309 #endif
 310 }
 311
 312 /**
 313  * hb_subset_plan_create:
 314  * Computes a plan for subsetting the supplied face according
 315  * to a provided input. The plan describes
 316  * which tables and glyphs should be retained.
 317  *
 318  * Return value: New subset plan.
 319  *
 320  * Since: 1.7.5
 321  **/
 322 hb_subset_plan_t *
 323 hb_subset_plan_create (hb_face_t         *face,
 324                        hb_subset_input_t *input)
 325 {
 326   hb_subset_plan_t *plan = hb_object_create<hb_subset_plan_t> ();
 327
 328   plan->drop_hints = input->drop_hints;
 329   plan->desubroutinize = input->desubroutinize;
 330   plan->retain_gids = input->retain_gids;
 331   plan->name_legacy = input->name_legacy;
 332   plan->unicodes = hb_set_create ();
 333   plan->name_ids = hb_set_reference (input->name_ids);
 334   _nameid_closure (face, plan->name_ids);
 335   plan->name_languages = hb_set_reference (input->name_languages);
 336   plan->glyphs_requested = hb_set_reference (input->glyphs);
 337   plan->drop_tables = hb_set_reference (input->drop_tables);
 338   plan->source = hb_face_reference (face);
 339   plan->dest = hb_face_builder_create ();
 340
 341   plan->_glyphset = hb_set_create ();
 342   plan->_glyphset_gsub = hb_set_create ();
 343   plan->codepoint_to_glyph = hb_map_create ();
 344   plan->glyph_map = hb_map_create ();
 345   plan->reverse_glyph_map = hb_map_create ();
 346   plan->gsub_lookups = hb_map_create ();
 347   plan->gpos_lookups = hb_map_create ();
 348   plan->gsub_features = hb_map_create ();
 349   plan->gpos_features = hb_map_create ();
 350   plan->layout_variation_indices = hb_set_create ();
 351   plan->layout_variation_idx_map = hb_map_create ();
 352
 353   _populate_gids_to_retain (plan,
 354                             input->unicodes,
 355                             input->glyphs,
 356                             !input->drop_tables->has (HB_OT_TAG_GSUB),
 357                             !input->drop_tables->has (HB_OT_TAG_GPOS),
 358                             !input->drop_tables->has (HB_OT_TAG_GDEF));
 359
 360   _create_old_gid_to_new_gid_map (face,
 361                                   input->retain_gids,
 362                                   plan->_glyphset,
 363                                   plan->glyph_map,
 364                                   plan->reverse_glyph_map,
 365                                   &plan->_num_output_glyphs);
 366
 367   return plan;
 368 }
 369
 370 /**
 371  * hb_subset_plan_destroy:
 372  *
 373  * Since: 1.7.5
 374  **/
 375 void
 376 hb_subset_plan_destroy (hb_subset_plan_t *plan)
 377 {
 378   if (!hb_object_destroy (plan)) return;
 379
 380   hb_set_destroy (plan->unicodes);
 381   hb_set_destroy (plan->name_ids);
 382   hb_set_destroy (plan->name_languages);
 383   hb_set_destroy (plan->glyphs_requested);
 384   hb_set_destroy (plan->drop_tables);
 385   hb_face_destroy (plan->source);
 386   hb_face_destroy (plan->dest);
 387   hb_map_destroy (plan->codepoint_to_glyph);
 388   hb_map_destroy (plan->glyph_map);
 389   hb_map_destroy (plan->reverse_glyph_map);
 390   hb_set_destroy (plan->_glyphset);
 391   hb_set_destroy (plan->_glyphset_gsub);
 392   hb_map_destroy (plan->gsub_lookups);
 393   hb_map_destroy (plan->gpos_lookups);
 394   hb_map_destroy (plan->gsub_features);
 395   hb_map_destroy (plan->gpos_features);
 396   hb_set_destroy (plan->layout_variation_indices);
 397   hb_map_destroy (plan->layout_variation_idx_map);
 398
 399
 400   free (plan);
 401 }