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  *     FreeType works in 26.6 mode.  Clients can decide to use that mode, and everything
  55  *     would work fine.  However, we also abuse this API for performing in font-space,
  56  *     but don't pass the correct flags to FreeType.  We just abuse the no-hinting mode
  57  *     for that, such that no rounding etc happens.  As such, we don't set ppem, and
  58  *     pass NO_HINTING around.  This seems to work best, until we go ahead and add a full
  59  *     load_flags API.
  60  *
  61  *   - We don't handle / allow for emboldening / obliqueing.
  62  *
  63  *   - In the future, we should add constructors to create fonts in font space?
  64  *
  65  *   - FT_Load_Glyph() is exteremely costly.  Do something about it?
  66  */
  67
  68
  69 static hb_bool_t
  70 hb_ft_get_glyph (hb_font_t *font HB_UNUSED,
  71                  void *font_data,
  72                  hb_codepoint_t unicode,
  73                  hb_codepoint_t variation_selector,
  74                  hb_codepoint_t *glyph,
  75                  void *user_data HB_UNUSED)
  76
  77 {
  78   FT_Face ft_face = (FT_Face) font_data;
  79
  80   if (unlikely (variation_selector)) {
  81     *glyph = FT_Face_GetCharVariantIndex (ft_face, unicode, variation_selector);
  82     return *glyph != 0;
  83   }
  84
  85   *glyph = FT_Get_Char_Index (ft_face, unicode);
  86   return *glyph != 0;
  87 }
  88
  89 static hb_position_t
  90 hb_ft_get_glyph_h_advance (hb_font_t *font HB_UNUSED,
  91                            void *font_data,
  92                            hb_codepoint_t glyph,
  93                            void *user_data HB_UNUSED)
  94 {
  95   FT_Face ft_face = (FT_Face) font_data;
  96   int load_flags = FT_LOAD_DEFAULT | FT_LOAD_NO_HINTING;
  97   FT_Fixed v;
  98
  99   if (unlikely (FT_Get_Advance (ft_face, glyph, load_flags, &v)))
 100     return 0;
 101
 102   if (font->x_scale < 0)
 103     v = -v;
 104
 105   return (v + (1<<9)) >> 10;
 106 }
 107
 108 static hb_position_t
 109 hb_ft_get_glyph_v_advance (hb_font_t *font HB_UNUSED,
 110                            void *font_data,
 111                            hb_codepoint_t glyph,
 112                            void *user_data HB_UNUSED)
 113 {
 114   FT_Face ft_face = (FT_Face) font_data;
 115   int load_flags = FT_LOAD_DEFAULT | FT_LOAD_NO_HINTING | FT_LOAD_VERTICAL_LAYOUT;
 116   FT_Fixed v;
 117
 118   if (unlikely (FT_Get_Advance (ft_face, glyph, load_flags, &v)))
 119     return 0;
 120
 121   if (font->y_scale < 0)
 122     v = -v;
 123
 124   /* Note: FreeType's vertical metrics grows downward while other FreeType coordinates
 125    * have a Y growing upward.  Hence the extra negation. */
 126   return (-v + (1<<9)) >> 10;
 127 }
 128
 129 static hb_bool_t
 130 hb_ft_get_glyph_h_origin (hb_font_t *font HB_UNUSED,
 131                           void *font_data HB_UNUSED,
 132                           hb_codepoint_t glyph HB_UNUSED,
 133                           hb_position_t *x HB_UNUSED,
 134                           hb_position_t *y HB_UNUSED,
 135                           void *user_data HB_UNUSED)
 136 {
 137   /* We always work in the horizontal coordinates. */
 138   return true;
 139 }
 140
 141 static hb_bool_t
 142 hb_ft_get_glyph_v_origin (hb_font_t *font HB_UNUSED,
 143                           void *font_data,
 144                           hb_codepoint_t glyph,
 145                           hb_position_t *x,
 146                           hb_position_t *y,
 147                           void *user_data HB_UNUSED)
 148 {
 149   FT_Face ft_face = (FT_Face) font_data;
 150   int load_flags = FT_LOAD_DEFAULT | FT_LOAD_NO_HINTING;
 151
 152   if (unlikely (FT_Load_Glyph (ft_face, glyph, load_flags)))
 153     return false;
 154
 155   /* Note: FreeType's vertical metrics grows downward while other FreeType coordinates
 156    * have a Y growing upward.  Hence the extra negation. */
 157   *x = ft_face->glyph->metrics.horiBearingX -   ft_face->glyph->metrics.vertBearingX;
 158   *y = ft_face->glyph->metrics.horiBearingY - (-ft_face->glyph->metrics.vertBearingY);
 159
 160   if (font->x_scale < 0)
 161     *x = -*x;
 162   if (font->y_scale < 0)
 163     *y = -*y;
 164
 165   return true;
 166 }
 167
 168 static hb_position_t
 169 hb_ft_get_glyph_h_kerning (hb_font_t *font,
 170                            void *font_data,
 171                            hb_codepoint_t left_glyph,
 172                            hb_codepoint_t right_glyph,
 173                            void *user_data HB_UNUSED)
 174 {
 175   FT_Face ft_face = (FT_Face) font_data;
 176   FT_Vector kerningv;
 177
 178   FT_Kerning_Mode mode = font->x_ppem ? FT_KERNING_DEFAULT : FT_KERNING_UNFITTED;
 179   if (FT_Get_Kerning (ft_face, left_glyph, right_glyph, mode, &kerningv))
 180     return 0;
 181
 182   return kerningv.x;
 183 }
 184
 185 static hb_position_t
 186 hb_ft_get_glyph_v_kerning (hb_font_t *font HB_UNUSED,
 187                            void *font_data HB_UNUSED,
 188                            hb_codepoint_t top_glyph HB_UNUSED,
 189                            hb_codepoint_t bottom_glyph HB_UNUSED,
 190                            void *user_data HB_UNUSED)
 191 {
 192   /* FreeType API doesn't support vertical kerning */
 193   return 0;
 194 }
 195
 196 static hb_bool_t
 197 hb_ft_get_glyph_extents (hb_font_t *font HB_UNUSED,
 198                          void *font_data,
 199                          hb_codepoint_t glyph,
 200                          hb_glyph_extents_t *extents,
 201                          void *user_data HB_UNUSED)
 202 {
 203   FT_Face ft_face = (FT_Face) font_data;
 204   int load_flags = FT_LOAD_DEFAULT | FT_LOAD_NO_HINTING;
 205
 206   if (unlikely (FT_Load_Glyph (ft_face, glyph, load_flags)))
 207     return false;
 208
 209   extents->x_bearing = ft_face->glyph->metrics.horiBearingX;
 210   extents->y_bearing = ft_face->glyph->metrics.horiBearingY;
 211   extents->width = ft_face->glyph->metrics.width;
 212   extents->height = -ft_face->glyph->metrics.height;
 213   return true;
 214 }
 215
 216 static hb_bool_t
 217 hb_ft_get_glyph_contour_point (hb_font_t *font HB_UNUSED,
 218                                void *font_data,
 219                                hb_codepoint_t glyph,
 220                                unsigned int point_index,
 221                                hb_position_t *x,
 222                                hb_position_t *y,
 223                                void *user_data HB_UNUSED)
 224 {
 225   FT_Face ft_face = (FT_Face) font_data;
 226   int load_flags = FT_LOAD_DEFAULT;
 227
 228   if (unlikely (FT_Load_Glyph (ft_face, glyph, load_flags)))
 229       return false;
 230
 231   if (unlikely (ft_face->glyph->format != FT_GLYPH_FORMAT_OUTLINE))
 232       return false;
 233
 234   if (unlikely (point_index >= (unsigned int) ft_face->glyph->outline.n_points))
 235       return false;
 236
 237   *x = ft_face->glyph->outline.points[point_index].x;
 238   *y = ft_face->glyph->outline.points[point_index].y;
 239
 240   return true;
 241 }
 242
 243 static hb_bool_t
 244 hb_ft_get_glyph_name (hb_font_t *font HB_UNUSED,
 245                       void *font_data,
 246                       hb_codepoint_t glyph,
 247                       char *name, unsigned int size,
 248                       void *user_data HB_UNUSED)
 249 {
 250   FT_Face ft_face = (FT_Face) font_data;
 251
 252   hb_bool_t ret = !FT_Get_Glyph_Name (ft_face, glyph, name, size);
 253   if (ret && (size && !*name))
 254     ret = false;
 255
 256   return ret;
 257 }
 258
 259 static hb_bool_t
 260 hb_ft_get_glyph_from_name (hb_font_t *font HB_UNUSED,
 261                            void *font_data,
 262                            const char *name, int len, /* -1 means nul-terminated */
 263                            hb_codepoint_t *glyph,
 264                            void *user_data HB_UNUSED)
 265 {
 266   FT_Face ft_face = (FT_Face) font_data;
 267
 268   if (len < 0)
 269     *glyph = FT_Get_Name_Index (ft_face, (FT_String *) name);
 270   else {
 271     /* Make a nul-terminated version. */
 272     char buf[128];
 273     len = MIN (len, (int) sizeof (buf) - 1);
 274     strncpy (buf, name, len);
 275     buf[len] = '\0';
 276     *glyph = FT_Get_Name_Index (ft_face, buf);
 277   }
 278
 279   if (*glyph == 0)
 280   {
 281     /* Check whether the given name was actually the name of glyph 0. */
 282     char buf[128];
 283     if (!FT_Get_Glyph_Name(ft_face, 0, buf, sizeof (buf)) &&
 284         len < 0 ? !strcmp (buf, name) : !strncmp (buf, name, len))
 285       return true;
 286   }
 287
 288   return *glyph != 0;
 289 }
 290
 291
 292 static hb_font_funcs_t *
 293 _hb_ft_get_font_funcs (void)
 294 {
 295   static const hb_font_funcs_t ft_ffuncs = {
 296     HB_OBJECT_HEADER_STATIC,
 297
 298     true, /* immutable */
 299
 300     {
 301 #define HB_FONT_FUNC_IMPLEMENT(name) hb_ft_get_##name,
 302       HB_FONT_FUNCS_IMPLEMENT_CALLBACKS
 303 #undef HB_FONT_FUNC_IMPLEMENT
 304     }
 305   };
 306
 307   return const_cast<hb_font_funcs_t *> (&ft_ffuncs);
 308 }
 309
 310
 311 static hb_blob_t *
 312 reference_table  (hb_face_t *face HB_UNUSED, hb_tag_t tag, void *user_data)
 313 {
 314   FT_Face ft_face = (FT_Face) user_data;
 315   FT_Byte *buffer;
 316   FT_ULong  length = 0;
 317   FT_Error error;
 318
 319   /* Note: FreeType like HarfBuzz uses the NONE tag for fetching the entire blob */
 320
 321   error = FT_Load_Sfnt_Table (ft_face, tag, 0, NULL, &length);
 322   if (error)
 323     return NULL;
 324
 325   buffer = (FT_Byte *) malloc (length);
 326   if (buffer == NULL)
 327     return NULL;
 328
 329   error = FT_Load_Sfnt_Table (ft_face, tag, 0, buffer, &length);
 330   if (error)
 331     return NULL;
 332
 333   return hb_blob_create ((const char *) buffer, length,
 334                          HB_MEMORY_MODE_WRITABLE,
 335                          buffer, free);
 336 }
 337
 338 /**
 339  * hb_ft_face_create:
 340  * @ft_face: (destroy destroy) (scope notified):
 341  * @destroy:
 342  *
 343  *
 344  *
 345  * Return value: (transfer full):
 346  * Since: 1.0
 347  **/
 348 hb_face_t *
 349 hb_ft_face_create (FT_Face           ft_face,
 350                    hb_destroy_func_t destroy)
 351 {
 352   hb_face_t *face;
 353
 354   if (ft_face->stream->read == NULL) {
 355     hb_blob_t *blob;
 356
 357     blob = hb_blob_create ((const char *) ft_face->stream->base,
 358                            (unsigned int) ft_face->stream->size,
 359                            HB_MEMORY_MODE_READONLY,
 360                            ft_face, destroy);
 361     face = hb_face_create (blob, ft_face->face_index);
 362     hb_blob_destroy (blob);
 363   } else {
 364     face = hb_face_create_for_tables (reference_table, ft_face, destroy);
 365   }
 366
 367   hb_face_set_index (face, ft_face->face_index);
 368   hb_face_set_upem (face, ft_face->units_per_EM);
 369
 370   return face;
 371 }
 372
 373 /**
 374  * hb_ft_face_create_referenced:
 375  * @ft_face:
 376  *
 377  *
 378  *
 379  * Return value: (transfer full):
 380  * Since: 1.0
 381  **/
 382 hb_face_t *
 383 hb_ft_face_create_referenced (FT_Face ft_face)
 384 {
 385   FT_Reference_Face (ft_face);
 386   return hb_ft_face_create (ft_face, (hb_destroy_func_t) FT_Done_Face);
 387 }
 388
 389 static void
 390 hb_ft_face_finalize (FT_Face ft_face)
 391 {
 392   hb_face_destroy ((hb_face_t *) ft_face->generic.data);
 393 }
 394
 395 /**
 396  * hb_ft_face_create_cached:
 397  * @ft_face:
 398  *
 399  *
 400  *
 401  * Return value: (transfer full):
 402  * Since: 1.0
 403  **/
 404 hb_face_t *
 405 hb_ft_face_create_cached (FT_Face ft_face)
 406 {
 407   if (unlikely (!ft_face->generic.data || ft_face->generic.finalizer != (FT_Generic_Finalizer) hb_ft_face_finalize))
 408   {
 409     if (ft_face->generic.finalizer)
 410       ft_face->generic.finalizer (ft_face);
 411
 412     ft_face->generic.data = hb_ft_face_create (ft_face, NULL);
 413     ft_face->generic.finalizer = (FT_Generic_Finalizer) hb_ft_face_finalize;
 414   }
 415
 416   return hb_face_reference ((hb_face_t *) ft_face->generic.data);
 417 }
 418
 419 static void
 420 _do_nothing (void)
 421 {
 422 }
 423
 424
 425 /**
 426  * hb_ft_font_create:
 427  * @ft_face: (destroy destroy) (scope notified):
 428  * @destroy:
 429  *
 430  *
 431  *
 432  * Return value: (transfer full):
 433  * Since: 1.0
 434  **/
 435 hb_font_t *
 436 hb_ft_font_create (FT_Face           ft_face,
 437                    hb_destroy_func_t destroy)
 438 {
 439   hb_font_t *font;
 440   hb_face_t *face;
 441
 442   face = hb_ft_face_create (ft_face, destroy);
 443   font = hb_font_create (face);
 444   hb_face_destroy (face);
 445   hb_font_set_funcs (font,
 446                      _hb_ft_get_font_funcs (),
 447                      ft_face, (hb_destroy_func_t) _do_nothing);
 448   hb_font_set_scale (font,
 449                      (int) (((uint64_t) ft_face->size->metrics.x_scale * (uint64_t) ft_face->units_per_EM + (1<<15)) >> 16),
 450                      (int) (((uint64_t) ft_face->size->metrics.y_scale * (uint64_t) ft_face->units_per_EM + (1<<15)) >> 16));
 451 #if 0 /* hb-ft works in no-hinting model */
 452   hb_font_set_ppem (font,
 453                     ft_face->size->metrics.x_ppem,
 454                     ft_face->size->metrics.y_ppem);
 455 #endif
 456
 457   return font;
 458 }
 459
 460 /**
 461  * hb_ft_font_create_referenced:
 462  * @ft_face:
 463  *
 464  *
 465  *
 466  * Return value: (transfer full):
 467  * Since: 1.0
 468  **/
 469 hb_font_t *
 470 hb_ft_font_create_referenced (FT_Face ft_face)
 471 {
 472   FT_Reference_Face (ft_face);
 473   return hb_ft_font_create (ft_face, (hb_destroy_func_t) FT_Done_Face);
 474 }
 475
 476
 477 /* Thread-safe, lock-free, FT_Library */
 478
 479 static FT_Library ft_library;
 480
 481 #ifdef HB_USE_ATEXIT
 482 static
 483 void free_ft_library (void)
 484 {
 485   FT_Done_FreeType (ft_library);
 486 }
 487 #endif
 488
 489 static FT_Library
 490 get_ft_library (void)
 491 {
 492 retry:
 493   FT_Library library = (FT_Library) hb_atomic_ptr_get (&ft_library);
 494
 495   if (unlikely (!library))
 496   {
 497     /* Not found; allocate one. */
 498     if (FT_Init_FreeType (&library))
 499       return NULL;
 500
 501     if (!hb_atomic_ptr_cmpexch (&ft_library, NULL, library)) {
 502       FT_Done_FreeType (library);
 503       goto retry;
 504     }
 505
 506 #ifdef HB_USE_ATEXIT
 507     atexit (free_ft_library); /* First person registers atexit() callback. */
 508 #endif
 509   }
 510
 511   return library;
 512 }
 513
 514 static void
 515 _release_blob (FT_Face ft_face)
 516 {
 517   hb_blob_destroy ((hb_blob_t *) ft_face->generic.data);
 518 }
 519
 520 void
 521 hb_ft_font_set_funcs (hb_font_t *font)
 522 {
 523   hb_blob_t *blob = hb_face_reference_blob (font->face);
 524   unsigned int blob_length;
 525   const char *blob_data = hb_blob_get_data (blob, &blob_length);
 526   if (unlikely (!blob_length))
 527     DEBUG_MSG (FT, font, "Font face has empty blob");
 528
 529   FT_Face ft_face = NULL;
 530   FT_Error err = FT_New_Memory_Face (get_ft_library (),
 531                                      (const FT_Byte *) blob_data,
 532                                      blob_length,
 533                                      hb_face_get_index (font->face),
 534                                      &ft_face);
 535
 536   if (unlikely (err)) {
 537     hb_blob_destroy (blob);
 538     DEBUG_MSG (FT, font, "Font face FT_New_Memory_Face() failed");
 539     return;
 540   }
 541
 542   FT_Select_Charmap (ft_face, FT_ENCODING_UNICODE);
 543
 544   FT_Set_Char_Size (ft_face,
 545                     abs (font->x_scale), abs (font->y_scale),
 546                     0, 0);
 547 #if 0
 548                     font->x_ppem * 72 * 64 / font->x_scale,
 549                     font->y_ppem * 72 * 64 / font->y_scale);
 550 #endif
 551   if (font->x_scale < 0 || font->y_scale < 0)
 552   {
 553     FT_Matrix matrix = { font->x_scale < 0 ? -1 : +1, 0,
 554                           0, font->y_scale < 0 ? -1 : +1};
 555     FT_Set_Transform (ft_face, &matrix, NULL);
 556   }
 557
 558   ft_face->generic.data = blob;
 559   ft_face->generic.finalizer = (FT_Generic_Finalizer) _release_blob;
 560
 561   hb_font_set_funcs (font,
 562                      _hb_ft_get_font_funcs (),
 563                      ft_face,
 564                      (hb_destroy_func_t) FT_Done_Face);
 565 }
 566
 567 FT_Face
 568 hb_ft_font_get_face (hb_font_t *font)
 569 {
 570   if (font->destroy == (hb_destroy_func_t) FT_Done_Face ||
 571       font->destroy == (hb_destroy_func_t) _do_nothing)
 572     return (FT_Face) font->user_data;
 573
 574   return NULL;
 575 }