third_party/harfbuzz-ng/src/hb-ot-font.cc

   1 /*
   2  * Copyright © 2011,2014  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, Roozbeh Pournader
  25  */
  26
  27 #include "hb-private.hh"
  28
  29 #include "hb-ot.h"
  30
  31 #include "hb-font-private.hh"
  32
  33 #include "hb-ot-cmap-table.hh"
  34 #include "hb-ot-hhea-table.hh"
  35 #include "hb-ot-hmtx-table.hh"
  36
  37
  38 struct hb_ot_face_metrics_accelerator_t
  39 {
  40   unsigned int num_metrics;
  41   unsigned int num_advances;
  42   unsigned int default_advance;
  43   const OT::_mtx *table;
  44   hb_blob_t *blob;
  45
  46   inline void init (hb_face_t *face,
  47                     hb_tag_t _hea_tag, hb_tag_t _mtx_tag,
  48                     unsigned int default_advance_)
  49   {
  50     this->default_advance = default_advance_;
  51     this->num_metrics = face->get_num_glyphs ();
  52
  53     hb_blob_t *_hea_blob = OT::Sanitizer<OT::_hea>::sanitize (face->reference_table (_hea_tag));
  54     const OT::_hea *_hea = OT::Sanitizer<OT::_hea>::lock_instance (_hea_blob);
  55     this->num_advances = _hea->numberOfLongMetrics;
  56     hb_blob_destroy (_hea_blob);
  57
  58     this->blob = OT::Sanitizer<OT::_mtx>::sanitize (face->reference_table (_mtx_tag));
  59     if (unlikely (!this->num_advances ||
  60                   2 * (this->num_advances + this->num_metrics) < hb_blob_get_length (this->blob)))
  61     {
  62       this->num_metrics = this->num_advances = 0;
  63       hb_blob_destroy (this->blob);
  64       this->blob = hb_blob_get_empty ();
  65     }
  66     this->table = OT::Sanitizer<OT::_mtx>::lock_instance (this->blob);
  67   }
  68
  69   inline void fini (void)
  70   {
  71     hb_blob_destroy (this->blob);
  72   }
  73
  74   inline unsigned int get_advance (hb_codepoint_t glyph) const
  75   {
  76     if (unlikely (glyph >= this->num_metrics))
  77     {
  78       /* If this->num_metrics is zero, it means we don't have the metrics table
  79        * for this direction: return one EM.  Otherwise, it means that the glyph
  80        * index is out of bound: return zero. */
  81       if (this->num_metrics)
  82         return 0;
  83       else
  84         return this->default_advance;
  85     }
  86
  87     if (glyph >= this->num_advances)
  88       glyph = this->num_advances - 1;
  89
  90     return this->table->longMetric[glyph].advance;
  91   }
  92 };
  93
  94 struct hb_ot_face_cmap_accelerator_t
  95 {
  96   const OT::CmapSubtable *table;
  97   const OT::CmapSubtable *uvs_table;
  98   hb_blob_t *blob;
  99
 100   inline void init (hb_face_t *face)
 101   {
 102     this->blob = OT::Sanitizer<OT::cmap>::sanitize (face->reference_table (HB_OT_TAG_cmap));
 103     const OT::cmap *cmap = OT::Sanitizer<OT::cmap>::lock_instance (this->blob);
 104     const OT::CmapSubtable *subtable = NULL;
 105     const OT::CmapSubtable *subtable_uvs = NULL;
 106
 107     /* 32-bit subtables. */
 108     if (!subtable) subtable = cmap->find_subtable (3, 10);
 109     if (!subtable) subtable = cmap->find_subtable (0, 6);
 110     if (!subtable) subtable = cmap->find_subtable (0, 4);
 111     /* 16-bit subtables. */
 112     if (!subtable) subtable = cmap->find_subtable (3, 1);
 113     if (!subtable) subtable = cmap->find_subtable (0, 3);
 114     if (!subtable) subtable = cmap->find_subtable (0, 2);
 115     if (!subtable) subtable = cmap->find_subtable (0, 1);
 116     if (!subtable) subtable = cmap->find_subtable (0, 0);
 117     if (!subtable) subtable = cmap->find_subtable (3, 0);
 118     /* Meh. */
 119     if (!subtable) subtable = &OT::Null(OT::CmapSubtable);
 120
 121     /* UVS subtable. */
 122     if (!subtable_uvs) subtable_uvs = cmap->find_subtable (0, 5);
 123     /* Meh. */
 124     if (!subtable_uvs) subtable_uvs = &OT::Null(OT::CmapSubtable);
 125
 126     this->table = subtable;
 127     this->uvs_table = subtable_uvs;
 128   }
 129
 130   inline void fini (void)
 131   {
 132     hb_blob_destroy (this->blob);
 133   }
 134
 135   inline bool get_glyph (hb_codepoint_t  unicode,
 136                          hb_codepoint_t  variation_selector,
 137                          hb_codepoint_t *glyph) const
 138   {
 139     if (unlikely (variation_selector))
 140     {
 141       switch (this->uvs_table->get_glyph_variant (unicode,
 142                                                   variation_selector,
 143                                                   glyph))
 144       {
 145         case OT::GLYPH_VARIANT_NOT_FOUND:       return false;
 146         case OT::GLYPH_VARIANT_FOUND:           return true;
 147         case OT::GLYPH_VARIANT_USE_DEFAULT:     break;
 148       }
 149     }
 150
 151     return this->table->get_glyph (unicode, glyph);
 152   }
 153 };
 154
 155
 156 struct hb_ot_font_t
 157 {
 158   hb_ot_face_cmap_accelerator_t cmap;
 159   hb_ot_face_metrics_accelerator_t h_metrics;
 160   hb_ot_face_metrics_accelerator_t v_metrics;
 161 };
 162
 163
 164 static hb_ot_font_t *
 165 _hb_ot_font_create (hb_font_t *font)
 166 {
 167   hb_ot_font_t *ot_font = (hb_ot_font_t *) calloc (1, sizeof (hb_ot_font_t));
 168   hb_face_t *face = font->face;
 169
 170   if (unlikely (!ot_font))
 171     return NULL;
 172
 173   unsigned int upem = face->get_upem ();
 174
 175   ot_font->cmap.init (face);
 176   ot_font->h_metrics.init (face, HB_OT_TAG_hhea, HB_OT_TAG_hmtx, upem>>1);
 177   ot_font->v_metrics.init (face, HB_OT_TAG_vhea, HB_OT_TAG_vmtx, upem); /* TODO Can we do this lazily? */
 178
 179   return ot_font;
 180 }
 181
 182 static void
 183 _hb_ot_font_destroy (hb_ot_font_t *ot_font)
 184 {
 185   ot_font->cmap.fini ();
 186   ot_font->h_metrics.fini ();
 187   ot_font->v_metrics.fini ();
 188
 189   free (ot_font);
 190 }
 191
 192
 193 static hb_bool_t
 194 hb_ot_get_glyph (hb_font_t *font HB_UNUSED,
 195                  void *font_data,
 196                  hb_codepoint_t unicode,
 197                  hb_codepoint_t variation_selector,
 198                  hb_codepoint_t *glyph,
 199                  void *user_data HB_UNUSED)
 200
 201 {
 202   const hb_ot_font_t *ot_font = (const hb_ot_font_t *) font_data;
 203   return ot_font->cmap.get_glyph (unicode, variation_selector, glyph);
 204 }
 205
 206 static hb_position_t
 207 hb_ot_get_glyph_h_advance (hb_font_t *font HB_UNUSED,
 208                            void *font_data,
 209                            hb_codepoint_t glyph,
 210                            void *user_data HB_UNUSED)
 211 {
 212   const hb_ot_font_t *ot_font = (const hb_ot_font_t *) font_data;
 213   return font->em_scale_x (ot_font->h_metrics.get_advance (glyph));
 214 }
 215
 216 static hb_position_t
 217 hb_ot_get_glyph_v_advance (hb_font_t *font HB_UNUSED,
 218                            void *font_data,
 219                            hb_codepoint_t glyph,
 220                            void *user_data HB_UNUSED)
 221 {
 222   const hb_ot_font_t *ot_font = (const hb_ot_font_t *) font_data;
 223   return font->em_scale_y (-(int) ot_font->v_metrics.get_advance (glyph));
 224 }
 225
 226 static hb_bool_t
 227 hb_ot_get_glyph_h_origin (hb_font_t *font HB_UNUSED,
 228                           void *font_data HB_UNUSED,
 229                           hb_codepoint_t glyph HB_UNUSED,
 230                           hb_position_t *x HB_UNUSED,
 231                           hb_position_t *y HB_UNUSED,
 232                           void *user_data HB_UNUSED)
 233 {
 234   /* We always work in the horizontal coordinates. */
 235   return true;
 236 }
 237
 238 static hb_bool_t
 239 hb_ot_get_glyph_v_origin (hb_font_t *font HB_UNUSED,
 240                           void *font_data,
 241                           hb_codepoint_t glyph,
 242                           hb_position_t *x,
 243                           hb_position_t *y,
 244                           void *user_data HB_UNUSED)
 245 {
 246   /* TODO */
 247   return false;
 248 }
 249
 250 static hb_position_t
 251 hb_ot_get_glyph_h_kerning (hb_font_t *font,
 252                            void *font_data,
 253                            hb_codepoint_t left_glyph,
 254                            hb_codepoint_t right_glyph,
 255                            void *user_data HB_UNUSED)
 256 {
 257   /* TODO */
 258   return 0;
 259 }
 260
 261 static hb_position_t
 262 hb_ot_get_glyph_v_kerning (hb_font_t *font HB_UNUSED,
 263                            void *font_data HB_UNUSED,
 264                            hb_codepoint_t top_glyph HB_UNUSED,
 265                            hb_codepoint_t bottom_glyph HB_UNUSED,
 266                            void *user_data HB_UNUSED)
 267 {
 268   /* OpenType doesn't have vertical-kerning other than GPOS. */
 269   return 0;
 270 }
 271
 272 static hb_bool_t
 273 hb_ot_get_glyph_extents (hb_font_t *font HB_UNUSED,
 274                          void *font_data,
 275                          hb_codepoint_t glyph,
 276                          hb_glyph_extents_t *extents,
 277                          void *user_data HB_UNUSED)
 278 {
 279   /* TODO */
 280   return false;
 281 }
 282
 283 static hb_bool_t
 284 hb_ot_get_glyph_contour_point (hb_font_t *font HB_UNUSED,
 285                                void *font_data,
 286                                hb_codepoint_t glyph,
 287                                unsigned int point_index,
 288                                hb_position_t *x,
 289                                hb_position_t *y,
 290                                void *user_data HB_UNUSED)
 291 {
 292   /* TODO */
 293   return false;
 294 }
 295
 296 static hb_bool_t
 297 hb_ot_get_glyph_name (hb_font_t *font HB_UNUSED,
 298                       void *font_data,
 299                       hb_codepoint_t glyph,
 300                       char *name, unsigned int size,
 301                       void *user_data HB_UNUSED)
 302 {
 303   /* TODO */
 304   return false;
 305 }
 306
 307 static hb_bool_t
 308 hb_ot_get_glyph_from_name (hb_font_t *font HB_UNUSED,
 309                            void *font_data,
 310                            const char *name, int len, /* -1 means nul-terminated */
 311                            hb_codepoint_t *glyph,
 312                            void *user_data HB_UNUSED)
 313 {
 314   /* TODO */
 315   return false;
 316 }
 317
 318
 319 static hb_font_funcs_t *
 320 _hb_ot_get_font_funcs (void)
 321 {
 322   static const hb_font_funcs_t ot_ffuncs = {
 323     HB_OBJECT_HEADER_STATIC,
 324
 325     true, /* immutable */
 326
 327     {
 328 #define HB_FONT_FUNC_IMPLEMENT(name) hb_ot_get_##name,
 329       HB_FONT_FUNCS_IMPLEMENT_CALLBACKS
 330 #undef HB_FONT_FUNC_IMPLEMENT
 331     }
 332   };
 333
 334   return const_cast<hb_font_funcs_t *> (&ot_ffuncs);
 335 }
 336
 337
 338 /**
 339  * Since: 0.9.28
 340  **/
 341 void
 342 hb_ot_font_set_funcs (hb_font_t *font)
 343 {
 344   hb_ot_font_t *ot_font = _hb_ot_font_create (font);
 345   if (unlikely (!ot_font))
 346     return;
 347
 348   hb_font_set_funcs (font,
 349                      _hb_ot_get_font_funcs (),
 350                      ot_font,
 351                      (hb_destroy_func_t) _hb_ot_font_destroy);
 352 }