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

   1 /*
   2  * Copyright © 2009  Red Hat, Inc.
   3  * Copyright © 2009  Keith Stribley
   4  *
   5  *  This is part of HarfBuzz, a text shaping library.
   6  *
   7  * Permission is hereby granted, without written agreement and without
   8  * license or royalty fees, to use, copy, modify, and distribute this
   9  * software and its documentation for any purpose, provided that the
  10  * above copyright notice and the following two paragraphs appear in
  11  * all copies of this software.
  12  *
  13  * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
  14  * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
  15  * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
  16  * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
  17  * DAMAGE.
  18  *
  19  * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
  20  * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
  21  * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
  22  * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
  23  * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
  24  *
  25  * Red Hat Author(s): Behdad Esfahbod
  26  */
  27
  28 #include "hb-private.hh"
  29
  30 #include "hb-ft.h"
  31
  32 #include "hb-font-private.hh"
  33
  34 #include FT_ADVANCES_H
  35 #include FT_TRUETYPE_TABLES_H
  36
  37
  38
  39 #ifndef HB_DEBUG_FT
  40 #define HB_DEBUG_FT (HB_DEBUG+0)
  41 #endif
  42
  43
  44 /* TODO:
  45  *
  46  * In general, this file does a fine job of what it's supposed to do.
  47  * There are, however, things that need more work:
  48  *
  49  *   - We don't handle any load_flags.  That definitely has API implications. :(
  50  *     I believe hb_ft_font_create() should take load_flags input.
  51  *     In particular, FT_Get_Advance() without the NO_HINTING flag seems to be
  52  *     buggy.
  53  *
  54  *   - We don't handle / allow for emboldening / obliqueing.
  55  *
  56  *   - In the future, we should add constructors to create fonts in font space?
  57  *
  58  *   - FT_Load_Glyph() is exteremely costly.  Do something about it?
  59  */
  60
  61
  62 static hb_bool_t
  63 hb_ft_get_glyph (hb_font_t *font HB_UNUSED,
  64                  void *font_data,
  65                  hb_codepoint_t unicode,
  66                  hb_codepoint_t variation_selector,
  67                  hb_codepoint_t *glyph,
  68                  void *user_data HB_UNUSED)
  69
  70 {
  71   FT_Face ft_face = (FT_Face) font_data;
  72
  73 #ifdef HAVE_FT_FACE_GETCHARVARIANTINDEX
  74   if (unlikely (variation_selector)) {
  75     *glyph = FT_Face_GetCharVariantIndex (ft_face, unicode, variation_selector);
  76     return *glyph != 0;
  77   }
  78 #endif
  79
  80   *glyph = FT_Get_Char_Index (ft_face, unicode);
  81   return *glyph != 0;
  82 }
  83
  84 static hb_position_t
  85 hb_ft_get_glyph_h_advance (hb_font_t *font HB_UNUSED,
  86                            void *font_data,
  87                            hb_codepoint_t glyph,
  88                            void *user_data HB_UNUSED)
  89 {
  90   FT_Face ft_face = (FT_Face) font_data;
  91   int load_flags = FT_LOAD_DEFAULT | FT_LOAD_NO_HINTING;
  92   FT_Fixed v;
  93
  94   if (unlikely (FT_Get_Advance (ft_face, glyph, load_flags, &v)))
  95     return 0;
  96
  97   return (v + (1<<9)) >> 10;
  98 }
  99
 100 static hb_position_t
 101 hb_ft_get_glyph_v_advance (hb_font_t *font HB_UNUSED,
 102                            void *font_data,
 103                            hb_codepoint_t glyph,
 104                            void *user_data HB_UNUSED)
 105 {
 106   FT_Face ft_face = (FT_Face) font_data;
 107   int load_flags = FT_LOAD_DEFAULT | FT_LOAD_NO_HINTING | FT_LOAD_VERTICAL_LAYOUT;
 108   FT_Fixed v;
 109
 110   if (unlikely (FT_Get_Advance (ft_face, glyph, load_flags, &v)))
 111     return 0;
 112
 113   /* Note: FreeType's vertical metrics grows downward while other FreeType coordinates
 114    * have a Y growing upward.  Hence the extra negation. */
 115   return (-v + (1<<9)) >> 10;
 116 }
 117
 118 static hb_bool_t
 119 hb_ft_get_glyph_h_origin (hb_font_t *font HB_UNUSED,
 120                           void *font_data HB_UNUSED,
 121                           hb_codepoint_t glyph HB_UNUSED,
 122                           hb_position_t *x HB_UNUSED,
 123                           hb_position_t *y HB_UNUSED,
 124                           void *user_data HB_UNUSED)
 125 {
 126   /* We always work in the horizontal coordinates. */
 127   return true;
 128 }
 129
 130 static hb_bool_t
 131 hb_ft_get_glyph_v_origin (hb_font_t *font HB_UNUSED,
 132                           void *font_data,
 133                           hb_codepoint_t glyph,
 134                           hb_position_t *x,
 135                           hb_position_t *y,
 136                           void *user_data HB_UNUSED)
 137 {
 138   FT_Face ft_face = (FT_Face) font_data;
 139   int load_flags = FT_LOAD_DEFAULT;
 140
 141   if (unlikely (FT_Load_Glyph (ft_face, glyph, load_flags)))
 142     return false;
 143
 144   /* Note: FreeType's vertical metrics grows downward while other FreeType coordinates
 145    * have a Y growing upward.  Hence the extra negation. */
 146   *x = ft_face->glyph->metrics.horiBearingX -   ft_face->glyph->metrics.vertBearingX;
 147   *y = ft_face->glyph->metrics.horiBearingY - (-ft_face->glyph->metrics.vertBearingY);
 148
 149   return true;
 150 }
 151
 152 static hb_position_t
 153 hb_ft_get_glyph_h_kerning (hb_font_t *font,
 154                            void *font_data,
 155                            hb_codepoint_t left_glyph,
 156                            hb_codepoint_t right_glyph,
 157                            void *user_data HB_UNUSED)
 158 {
 159   FT_Face ft_face = (FT_Face) font_data;
 160   FT_Vector kerningv;
 161
 162   FT_Kerning_Mode mode = font->x_ppem ? FT_KERNING_DEFAULT : FT_KERNING_UNFITTED;
 163   if (FT_Get_Kerning (ft_face, left_glyph, right_glyph, mode, &kerningv))
 164     return 0;
 165
 166   return kerningv.x;
 167 }
 168
 169 static hb_position_t
 170 hb_ft_get_glyph_v_kerning (hb_font_t *font HB_UNUSED,
 171                            void *font_data HB_UNUSED,
 172                            hb_codepoint_t top_glyph HB_UNUSED,
 173                            hb_codepoint_t bottom_glyph HB_UNUSED,
 174                            void *user_data HB_UNUSED)
 175 {
 176   /* FreeType API doesn't support vertical kerning */
 177   return 0;
 178 }
 179
 180 static hb_bool_t
 181 hb_ft_get_glyph_extents (hb_font_t *font HB_UNUSED,
 182                          void *font_data,
 183                          hb_codepoint_t glyph,
 184                          hb_glyph_extents_t *extents,
 185                          void *user_data HB_UNUSED)
 186 {
 187   FT_Face ft_face = (FT_Face) font_data;
 188   int load_flags = FT_LOAD_DEFAULT;
 189
 190   if (unlikely (FT_Load_Glyph (ft_face, glyph, load_flags)))
 191     return false;
 192
 193   extents->x_bearing = ft_face->glyph->metrics.horiBearingX;
 194   extents->y_bearing = ft_face->glyph->metrics.horiBearingY;
 195   extents->width = ft_face->glyph->metrics.width;
 196   extents->height = -ft_face->glyph->metrics.height;
 197   return true;
 198 }
 199
 200 static hb_bool_t
 201 hb_ft_get_glyph_contour_point (hb_font_t *font HB_UNUSED,
 202                                void *font_data,
 203                                hb_codepoint_t glyph,
 204                                unsigned int point_index,
 205                                hb_position_t *x,
 206                                hb_position_t *y,
 207                                void *user_data HB_UNUSED)
 208 {
 209   FT_Face ft_face = (FT_Face) font_data;
 210   int load_flags = FT_LOAD_DEFAULT;
 211
 212   if (unlikely (FT_Load_Glyph (ft_face, glyph, load_flags)))
 213       return false;
 214
 215   if (unlikely (ft_face->glyph->format != FT_GLYPH_FORMAT_OUTLINE))
 216       return false;
 217
 218   if (unlikely (point_index >= (unsigned int) ft_face->glyph->outline.n_points))
 219       return false;
 220
 221   *x = ft_face->glyph->outline.points[point_index].x;
 222   *y = ft_face->glyph->outline.points[point_index].y;
 223
 224   return true;
 225 }
 226
 227 static hb_bool_t
 228 hb_ft_get_glyph_name (hb_font_t *font HB_UNUSED,
 229                       void *font_data,
 230                       hb_codepoint_t glyph,
 231                       char *name, unsigned int size,
 232                       void *user_data HB_UNUSED)
 233 {
 234   FT_Face ft_face = (FT_Face) font_data;
 235
 236   hb_bool_t ret = !FT_Get_Glyph_Name (ft_face, glyph, name, size);
 237   if (ret && (size && !*name))
 238     ret = false;
 239
 240   return ret;
 241 }
 242
 243 static hb_bool_t
 244 hb_ft_get_glyph_from_name (hb_font_t *font HB_UNUSED,
 245                            void *font_data,
 246                            const char *name, int len, /* -1 means nul-terminated */
 247                            hb_codepoint_t *glyph,
 248                            void *user_data HB_UNUSED)
 249 {
 250   FT_Face ft_face = (FT_Face) font_data;
 251
 252   if (len < 0)
 253     *glyph = FT_Get_Name_Index (ft_face, (FT_String *) name);
 254   else {
 255     /* Make a nul-terminated version. */
 256     char buf[128];
 257     len = MIN (len, (int) sizeof (buf) - 1);
 258     strncpy (buf, name, len);
 259     buf[len] = '\0';
 260     *glyph = FT_Get_Name_Index (ft_face, buf);
 261   }
 262
 263   if (*glyph == 0)
 264   {
 265     /* Check whether the given name was actually the name of glyph 0. */
 266     char buf[128];
 267     if (!FT_Get_Glyph_Name(ft_face, 0, buf, sizeof (buf)) &&
 268         len < 0 ? !strcmp (buf, name) : !strncmp (buf, name, len))
 269       return true;
 270   }
 271
 272   return *glyph != 0;
 273 }
 274
 275
 276 static hb_font_funcs_t *
 277 _hb_ft_get_font_funcs (void)
 278 {
 279   static const hb_font_funcs_t ft_ffuncs = {
 280     HB_OBJECT_HEADER_STATIC,
 281
 282     true, /* immutable */
 283
 284     {
 285 #define HB_FONT_FUNC_IMPLEMENT(name) hb_ft_get_##name,
 286       HB_FONT_FUNCS_IMPLEMENT_CALLBACKS
 287 #undef HB_FONT_FUNC_IMPLEMENT
 288     }
 289   };
 290
 291   return const_cast<hb_font_funcs_t *> (&ft_ffuncs);
 292 }
 293
 294
 295 static hb_blob_t *
 296 reference_table  (hb_face_t *face HB_UNUSED, hb_tag_t tag, void *user_data)
 297 {
 298   FT_Face ft_face = (FT_Face) user_data;
 299   FT_Byte *buffer;
 300   FT_ULong  length = 0;
 301   FT_Error error;
 302
 303   /* Note: FreeType like HarfBuzz uses the NONE tag for fetching the entire blob */
 304
 305   error = FT_Load_Sfnt_Table (ft_face, tag, 0, NULL, &length);
 306   if (error)
 307     return NULL;
 308
 309   buffer = (FT_Byte *) malloc (length);
 310   if (buffer == NULL)
 311     return NULL;
 312
 313   error = FT_Load_Sfnt_Table (ft_face, tag, 0, buffer, &length);
 314   if (error)
 315     return NULL;
 316
 317   return hb_blob_create ((const char *) buffer, length,
 318                          HB_MEMORY_MODE_WRITABLE,
 319                          buffer, free);
 320 }
 321
 322 /**
 323  * hb_ft_face_create:
 324  * @ft_face: (destroy destroy) (scope notified):
 325  * @destroy:
 326  *
 327  *
 328  *
 329  * Return value: (transfer full):
 330  * Since: 1.0
 331  **/
 332 hb_face_t *
 333 hb_ft_face_create (FT_Face           ft_face,
 334                    hb_destroy_func_t destroy)
 335 {
 336   hb_face_t *face;
 337
 338   if (ft_face->stream->read == NULL) {
 339     hb_blob_t *blob;
 340
 341     blob = hb_blob_create ((const char *) ft_face->stream->base,
 342                            (unsigned int) ft_face->stream->size,
 343                            /* TODO: We assume that it's mmap()'ed, but FreeType code
 344                             * suggests that there are cases we reach here but font is
 345                             * not mmapped.  For example, when mmap() fails.  No idea
 346                             * how to deal with it better here. */
 347                            HB_MEMORY_MODE_READONLY_MAY_MAKE_WRITABLE,
 348                            ft_face, destroy);
 349     face = hb_face_create (blob, ft_face->face_index);
 350     hb_blob_destroy (blob);
 351   } else {
 352     face = hb_face_create_for_tables (reference_table, ft_face, destroy);
 353   }
 354
 355   hb_face_set_index (face, ft_face->face_index);
 356   hb_face_set_upem (face, ft_face->units_per_EM);
 357
 358   return face;
 359 }
 360
 361 static void
 362 hb_ft_face_finalize (FT_Face ft_face)
 363 {
 364   hb_face_destroy ((hb_face_t *) ft_face->generic.data);
 365 }
 366
 367 /**
 368  * hb_ft_face_create_cached:
 369  * @ft_face:
 370  *
 371  *
 372  *
 373  * Return value: (transfer full):
 374  * Since: 1.0
 375  **/
 376 hb_face_t *
 377 hb_ft_face_create_cached (FT_Face ft_face)
 378 {
 379   if (unlikely (!ft_face->generic.data || ft_face->generic.finalizer != (FT_Generic_Finalizer) hb_ft_face_finalize))
 380   {
 381     if (ft_face->generic.finalizer)
 382       ft_face->generic.finalizer (ft_face);
 383
 384     ft_face->generic.data = hb_ft_face_create (ft_face, NULL);
 385     ft_face->generic.finalizer = (FT_Generic_Finalizer) hb_ft_face_finalize;
 386   }
 387
 388   return hb_face_reference ((hb_face_t *) ft_face->generic.data);
 389 }
 390
 391 static void
 392 _do_nothing (void)
 393 {
 394 }
 395
 396
 397 /**
 398  * hb_ft_font_create:
 399  * @ft_face: (destroy destroy) (scope notified):
 400  * @destroy:
 401  *
 402  *
 403  *
 404  * Return value: (transfer full):
 405  * Since: 1.0
 406  **/
 407 hb_font_t *
 408 hb_ft_font_create (FT_Face           ft_face,
 409                    hb_destroy_func_t destroy)
 410 {
 411   hb_font_t *font;
 412   hb_face_t *face;
 413
 414   face = hb_ft_face_create (ft_face, destroy);
 415   font = hb_font_create (face);
 416   hb_face_destroy (face);
 417   hb_font_set_funcs (font,
 418                      _hb_ft_get_font_funcs (),
 419                      ft_face, (hb_destroy_func_t) _do_nothing);
 420   hb_font_set_scale (font,
 421                      (int) (((uint64_t) ft_face->size->metrics.x_scale * (uint64_t) ft_face->units_per_EM + (1<<15)) >> 16),
 422                      (int) (((uint64_t) ft_face->size->metrics.y_scale * (uint64_t) ft_face->units_per_EM + (1<<15)) >> 16));
 423   hb_font_set_ppem (font,
 424                     ft_face->size->metrics.x_ppem,
 425                     ft_face->size->metrics.y_ppem);
 426
 427   return font;
 428 }
 429
 430
 431 /* Thread-safe, lock-free, FT_Library */
 432
 433 static FT_Library ft_library;
 434
 435 static inline
 436 void free_ft_library (void)
 437 {
 438   FT_Done_FreeType (ft_library);
 439 }
 440
 441 static FT_Library
 442 get_ft_library (void)
 443 {
 444 retry:
 445   FT_Library library = (FT_Library) hb_atomic_ptr_get (&ft_library);
 446
 447   if (unlikely (!library))
 448   {
 449     /* Not found; allocate one. */
 450     if (FT_Init_FreeType (&library))
 451       return NULL;
 452
 453     if (!hb_atomic_ptr_cmpexch (&ft_library, NULL, library)) {
 454       FT_Done_FreeType (library);
 455       goto retry;
 456     }
 457
 458 #ifdef HAVE_ATEXIT
 459     atexit (free_ft_library); /* First person registers atexit() callback. */
 460 #endif
 461   }
 462
 463   return library;
 464 }
 465
 466 static void
 467 _release_blob (FT_Face ft_face)
 468 {
 469   hb_blob_destroy ((hb_blob_t *) ft_face->generic.data);
 470 }
 471
 472 void
 473 hb_ft_font_set_funcs (hb_font_t *font)
 474 {
 475   hb_blob_t *blob = hb_face_reference_blob (font->face);
 476   unsigned int blob_length;
 477   const char *blob_data = hb_blob_get_data (blob, &blob_length);
 478   if (unlikely (!blob_length))
 479     DEBUG_MSG (FT, font, "Font face has empty blob");
 480
 481   FT_Face ft_face = NULL;
 482   FT_Error err = FT_New_Memory_Face (get_ft_library (),
 483                                      (const FT_Byte *) blob_data,
 484                                      blob_length,
 485                                      hb_face_get_index (font->face),
 486                                      &ft_face);
 487
 488   if (unlikely (err)) {
 489     hb_blob_destroy (blob);
 490     DEBUG_MSG (FT, font, "Font face FT_New_Memory_Face() failed");
 491     return;
 492   }
 493
 494   FT_Select_Charmap (ft_face, FT_ENCODING_UNICODE);
 495
 496   assert (font->y_scale >= 0);
 497   FT_Set_Char_Size (ft_face,
 498                     font->x_scale, font->y_scale,
 499                     0, 0);
 500 #if 0
 501                     font->x_ppem * 72 * 64 / font->x_scale,
 502                     font->y_ppem * 72 * 64 / font->y_scale);
 503 #endif
 504
 505   ft_face->generic.data = blob;
 506   ft_face->generic.finalizer = (FT_Generic_Finalizer) _release_blob;
 507
 508   hb_font_set_funcs (font,
 509                      _hb_ft_get_font_funcs (),
 510                      ft_face,
 511                      (hb_destroy_func_t) FT_Done_Face);
 512 }
 513
 514 FT_Face
 515 hb_ft_font_get_face (hb_font_t *font)
 516 {
 517   if (font->destroy == (hb_destroy_func_t) FT_Done_Face ||
 518       font->destroy == (hb_destroy_func_t) _do_nothing)
 519     return (FT_Face) font->user_data;
 520
 521   return NULL;
 522 }