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
  39 struct hb_ot_font_t
  40 {
  41   unsigned int num_glyphs;
  42   unsigned int num_hmetrics;
  43   const OT::hmtx *hmtx;
  44   hb_blob_t *hmtx_blob;
  45
  46   const OT::CmapSubtable *cmap;
  47   const OT::CmapSubtable *cmap_uvs;
  48   hb_blob_t *cmap_blob;
  49 };
  50
  51
  52 static hb_ot_font_t *
  53 _hb_ot_font_create (hb_font_t *font)
  54 {
  55   hb_ot_font_t *ot_font = (hb_ot_font_t *) calloc (1, sizeof (hb_ot_font_t));
  56
  57   if (unlikely (!ot_font))
  58     return NULL;
  59
  60   ot_font->num_glyphs = font->face->get_num_glyphs ();
  61
  62   {
  63     hb_blob_t *hhea_blob = OT::Sanitizer<OT::hhea>::sanitize (font->face->reference_table (HB_OT_TAG_hhea));
  64     const OT::hhea *hhea = OT::Sanitizer<OT::hhea>::lock_instance (hhea_blob);
  65     ot_font->num_hmetrics = hhea->numberOfHMetrics;
  66     hb_blob_destroy (hhea_blob);
  67   }
  68   ot_font->hmtx_blob = OT::Sanitizer<OT::hmtx>::sanitize (font->face->reference_table (HB_OT_TAG_hmtx));
  69   if (unlikely (!ot_font->num_hmetrics ||
  70                 2 * (ot_font->num_hmetrics + ot_font->num_glyphs) < hb_blob_get_length (ot_font->hmtx_blob)))
  71   {
  72     hb_blob_destroy (ot_font->hmtx_blob);
  73     free (ot_font);
  74     return NULL;
  75   }
  76   ot_font->hmtx = OT::Sanitizer<OT::hmtx>::lock_instance (ot_font->hmtx_blob);
  77
  78   ot_font->cmap_blob = OT::Sanitizer<OT::cmap>::sanitize (font->face->reference_table (HB_OT_TAG_cmap));
  79   const OT::cmap *cmap = OT::Sanitizer<OT::cmap>::lock_instance (ot_font->cmap_blob);
  80   const OT::CmapSubtable *subtable = NULL;
  81   const OT::CmapSubtable *subtable_uvs = NULL;
  82
  83   /* 32-bit subtables. */
  84   if (!subtable) subtable = cmap->find_subtable (3, 10);
  85   if (!subtable) subtable = cmap->find_subtable (0, 6);
  86   if (!subtable) subtable = cmap->find_subtable (0, 4);
  87   /* 16-bit subtables. */
  88   if (!subtable) subtable = cmap->find_subtable (3, 1);
  89   if (!subtable) subtable = cmap->find_subtable (0, 3);
  90   if (!subtable) subtable = cmap->find_subtable (0, 2);
  91   if (!subtable) subtable = cmap->find_subtable (0, 1);
  92   if (!subtable) subtable = cmap->find_subtable (0, 0);
  93   /* Meh. */
  94   if (!subtable) subtable = &OT::Null(OT::CmapSubtable);
  95
  96   /* UVS subtable. */
  97   if (!subtable_uvs) subtable_uvs = cmap->find_subtable (0, 5);
  98   /* Meh. */
  99   if (!subtable_uvs) subtable_uvs = &OT::Null(OT::CmapSubtable);
 100
 101   ot_font->cmap = subtable;
 102   ot_font->cmap_uvs = subtable_uvs;
 103
 104   return ot_font;
 105 }
 106
 107 static void
 108 _hb_ot_font_destroy (hb_ot_font_t *ot_font)
 109 {
 110   hb_blob_destroy (ot_font->cmap_blob);
 111   hb_blob_destroy (ot_font->hmtx_blob);
 112
 113   free (ot_font);
 114 }
 115
 116
 117 static hb_bool_t
 118 hb_ot_get_glyph (hb_font_t *font HB_UNUSED,
 119                  void *font_data,
 120                  hb_codepoint_t unicode,
 121                  hb_codepoint_t variation_selector,
 122                  hb_codepoint_t *glyph,
 123                  void *user_data HB_UNUSED)
 124
 125 {
 126   const hb_ot_font_t *ot_font = (const hb_ot_font_t *) font_data;
 127
 128   if (unlikely (variation_selector))
 129   {
 130     switch (ot_font->cmap_uvs->get_glyph_variant (unicode,
 131                                                   variation_selector,
 132                                                   glyph))
 133     {
 134       case OT::GLYPH_VARIANT_NOT_FOUND:         return false;
 135       case OT::GLYPH_VARIANT_FOUND:             return true;
 136       case OT::GLYPH_VARIANT_USE_DEFAULT:       break;
 137     }
 138   }
 139
 140   return ot_font->cmap->get_glyph (unicode, glyph);
 141 }
 142
 143 static hb_position_t
 144 hb_ot_get_glyph_h_advance (hb_font_t *font HB_UNUSED,
 145                            void *font_data,
 146                            hb_codepoint_t glyph,
 147                            void *user_data HB_UNUSED)
 148 {
 149   const hb_ot_font_t *ot_font = (const hb_ot_font_t *) font_data;
 150
 151   if (unlikely (glyph >= ot_font->num_glyphs))
 152     return 0; /* Maybe better to return notdef's advance instead? */
 153
 154   if (glyph >= ot_font->num_hmetrics)
 155     glyph = ot_font->num_hmetrics - 1;
 156
 157   return font->em_scale_x (ot_font->hmtx->longHorMetric[glyph].advanceWidth);
 158 }
 159
 160 static hb_position_t
 161 hb_ot_get_glyph_v_advance (hb_font_t *font HB_UNUSED,
 162                            void *font_data,
 163                            hb_codepoint_t glyph,
 164                            void *user_data HB_UNUSED)
 165 {
 166   /* TODO */
 167   return 0;
 168 }
 169
 170 static hb_bool_t
 171 hb_ot_get_glyph_h_origin (hb_font_t *font HB_UNUSED,
 172                           void *font_data HB_UNUSED,
 173                           hb_codepoint_t glyph HB_UNUSED,
 174                           hb_position_t *x HB_UNUSED,
 175                           hb_position_t *y HB_UNUSED,
 176                           void *user_data HB_UNUSED)
 177 {
 178   /* We always work in the horizontal coordinates. */
 179   return true;
 180 }
 181
 182 static hb_bool_t
 183 hb_ot_get_glyph_v_origin (hb_font_t *font HB_UNUSED,
 184                           void *font_data,
 185                           hb_codepoint_t glyph,
 186                           hb_position_t *x,
 187                           hb_position_t *y,
 188                           void *user_data HB_UNUSED)
 189 {
 190   /* TODO */
 191   return false;
 192 }
 193
 194 static hb_position_t
 195 hb_ot_get_glyph_h_kerning (hb_font_t *font,
 196                            void *font_data,
 197                            hb_codepoint_t left_glyph,
 198                            hb_codepoint_t right_glyph,
 199                            void *user_data HB_UNUSED)
 200 {
 201   /* TODO */
 202   return 0;
 203 }
 204
 205 static hb_position_t
 206 hb_ot_get_glyph_v_kerning (hb_font_t *font HB_UNUSED,
 207                            void *font_data HB_UNUSED,
 208                            hb_codepoint_t top_glyph HB_UNUSED,
 209                            hb_codepoint_t bottom_glyph HB_UNUSED,
 210                            void *user_data HB_UNUSED)
 211 {
 212   return 0;
 213 }
 214
 215 static hb_bool_t
 216 hb_ot_get_glyph_extents (hb_font_t *font HB_UNUSED,
 217                          void *font_data,
 218                          hb_codepoint_t glyph,
 219                          hb_glyph_extents_t *extents,
 220                          void *user_data HB_UNUSED)
 221 {
 222   /* TODO */
 223   return false;
 224 }
 225
 226 static hb_bool_t
 227 hb_ot_get_glyph_contour_point (hb_font_t *font HB_UNUSED,
 228                                void *font_data,
 229                                hb_codepoint_t glyph,
 230                                unsigned int point_index,
 231                                hb_position_t *x,
 232                                hb_position_t *y,
 233                                void *user_data HB_UNUSED)
 234 {
 235   /* TODO */
 236   return false;
 237 }
 238
 239 static hb_bool_t
 240 hb_ot_get_glyph_name (hb_font_t *font HB_UNUSED,
 241                       void *font_data,
 242                       hb_codepoint_t glyph,
 243                       char *name, unsigned int size,
 244                       void *user_data HB_UNUSED)
 245 {
 246   /* TODO */
 247   return false;
 248 }
 249
 250 static hb_bool_t
 251 hb_ot_get_glyph_from_name (hb_font_t *font HB_UNUSED,
 252                            void *font_data,
 253                            const char *name, int len, /* -1 means nul-terminated */
 254                            hb_codepoint_t *glyph,
 255                            void *user_data HB_UNUSED)
 256 {
 257   /* TODO */
 258   return false;
 259 }
 260
 261
 262 static hb_font_funcs_t *
 263 _hb_ot_get_font_funcs (void)
 264 {
 265   static const hb_font_funcs_t ot_ffuncs = {
 266     HB_OBJECT_HEADER_STATIC,
 267
 268     true, /* immutable */
 269
 270     {
 271 #define HB_FONT_FUNC_IMPLEMENT(name) hb_ot_get_##name,
 272       HB_FONT_FUNCS_IMPLEMENT_CALLBACKS
 273 #undef HB_FONT_FUNC_IMPLEMENT
 274     }
 275   };
 276
 277   return const_cast<hb_font_funcs_t *> (&ot_ffuncs);
 278 }
 279
 280
 281 void
 282 hb_ot_font_set_funcs (hb_font_t *font)
 283 {
 284   hb_ot_font_t *ot_font = _hb_ot_font_create (font);
 285   if (unlikely (!ot_font))
 286     return;
 287
 288   hb_font_set_funcs (font,
 289                      _hb_ot_get_font_funcs (),
 290                      ot_font,
 291                      (hb_destroy_func_t) _hb_ot_font_destroy);
 292 }