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     if (*glyph)
  77       return true;
  78   }
  79 #endif
  80
  81   *glyph = FT_Get_Char_Index (ft_face, unicode);
  82   return *glyph != 0;
  83 }
  84
  85 static hb_position_t
  86 hb_ft_get_glyph_h_advance (hb_font_t *font HB_UNUSED,
  87                            void *font_data,
  88                            hb_codepoint_t glyph,
  89                            void *user_data HB_UNUSED)
  90 {
  91   FT_Face ft_face = (FT_Face) font_data;
  92   int load_flags = FT_LOAD_DEFAULT | FT_LOAD_NO_HINTING;
  93   FT_Fixed v;
  94
  95   if (unlikely (FT_Get_Advance (ft_face, glyph, load_flags, &v)))
  96     return 0;
  97
  98   return v >> 10;
  99 }
 100
 101 static hb_position_t
 102 hb_ft_get_glyph_v_advance (hb_font_t *font HB_UNUSED,
 103                            void *font_data,
 104                            hb_codepoint_t glyph,
 105                            void *user_data HB_UNUSED)
 106 {
 107   FT_Face ft_face = (FT_Face) font_data;
 108   int load_flags = FT_LOAD_DEFAULT | FT_LOAD_NO_HINTING | FT_LOAD_VERTICAL_LAYOUT;
 109   FT_Fixed v;
 110
 111   if (unlikely (FT_Get_Advance (ft_face, glyph, load_flags, &v)))
 112     return 0;
 113
 114   /* Note: FreeType's vertical metrics grows downward while other FreeType coordinates
 115    * have a Y growing upward.  Hence the extra negation. */
 116   return -v >> 10;
 117 }
 118
 119 static hb_bool_t
 120 hb_ft_get_glyph_h_origin (hb_font_t *font HB_UNUSED,
 121                           void *font_data HB_UNUSED,
 122                           hb_codepoint_t glyph HB_UNUSED,
 123                           hb_position_t *x HB_UNUSED,
 124                           hb_position_t *y HB_UNUSED,
 125                           void *user_data HB_UNUSED)
 126 {
 127   /* We always work in the horizontal coordinates. */
 128   return true;
 129 }
 130
 131 static hb_bool_t
 132 hb_ft_get_glyph_v_origin (hb_font_t *font HB_UNUSED,
 133                           void *font_data,
 134                           hb_codepoint_t glyph,
 135                           hb_position_t *x,
 136                           hb_position_t *y,
 137                           void *user_data HB_UNUSED)
 138 {
 139   FT_Face ft_face = (FT_Face) font_data;
 140   int load_flags = FT_LOAD_DEFAULT;
 141
 142   if (unlikely (FT_Load_Glyph (ft_face, glyph, load_flags)))
 143     return false;
 144
 145   /* Note: FreeType's vertical metrics grows downward while other FreeType coordinates
 146    * have a Y growing upward.  Hence the extra negation. */
 147   *x = ft_face->glyph->metrics.horiBearingX -   ft_face->glyph->metrics.vertBearingX;
 148   *y = ft_face->glyph->metrics.horiBearingY - (-ft_face->glyph->metrics.vertBearingY);
 149
 150   return true;
 151 }
 152
 153 static hb_position_t
 154 hb_ft_get_glyph_h_kerning (hb_font_t *font,
 155                            void *font_data,
 156                            hb_codepoint_t left_glyph,
 157                            hb_codepoint_t right_glyph,
 158                            void *user_data HB_UNUSED)
 159 {
 160   FT_Face ft_face = (FT_Face) font_data;
 161   FT_Vector kerningv;
 162
 163   FT_Kerning_Mode mode = font->x_ppem ? FT_KERNING_DEFAULT : FT_KERNING_UNFITTED;
 164   if (FT_Get_Kerning (ft_face, left_glyph, right_glyph, mode, &kerningv))
 165     return 0;
 166
 167   return kerningv.x;
 168 }
 169
 170 static hb_position_t
 171 hb_ft_get_glyph_v_kerning (hb_font_t *font HB_UNUSED,
 172                            void *font_data HB_UNUSED,
 173                            hb_codepoint_t top_glyph HB_UNUSED,
 174                            hb_codepoint_t bottom_glyph HB_UNUSED,
 175                            void *user_data HB_UNUSED)
 176 {
 177   /* FreeType API doesn't support vertical kerning */
 178   return 0;
 179 }
 180
 181 static hb_bool_t
 182 hb_ft_get_glyph_extents (hb_font_t *font HB_UNUSED,
 183                          void *font_data,
 184                          hb_codepoint_t glyph,
 185                          hb_glyph_extents_t *extents,
 186                          void *user_data HB_UNUSED)
 187 {
 188   FT_Face ft_face = (FT_Face) font_data;
 189   int load_flags = FT_LOAD_DEFAULT;
 190
 191   if (unlikely (FT_Load_Glyph (ft_face, glyph, load_flags)))
 192     return false;
 193
 194   extents->x_bearing = ft_face->glyph->metrics.horiBearingX;
 195   extents->y_bearing = ft_face->glyph->metrics.horiBearingY;
 196   extents->width = ft_face->glyph->metrics.width;
 197   extents->height = -ft_face->glyph->metrics.height;
 198   return true;
 199 }
 200
 201 static hb_bool_t
 202 hb_ft_get_glyph_contour_point (hb_font_t *font HB_UNUSED,
 203                                void *font_data,
 204                                hb_codepoint_t glyph,
 205                                unsigned int point_index,
 206                                hb_position_t *x,
 207                                hb_position_t *y,
 208                                void *user_data HB_UNUSED)
 209 {
 210   FT_Face ft_face = (FT_Face) font_data;
 211   int load_flags = FT_LOAD_DEFAULT;
 212
 213   if (unlikely (FT_Load_Glyph (ft_face, glyph, load_flags)))
 214       return false;
 215
 216   if (unlikely (ft_face->glyph->format != FT_GLYPH_FORMAT_OUTLINE))
 217       return false;
 218
 219   if (unlikely (point_index >= (unsigned int) ft_face->glyph->outline.n_points))
 220       return false;
 221
 222   *x = ft_face->glyph->outline.points[point_index].x;
 223   *y = ft_face->glyph->outline.points[point_index].y;
 224
 225   return true;
 226 }
 227
 228 static hb_bool_t
 229 hb_ft_get_glyph_name (hb_font_t *font HB_UNUSED,
 230                       void *font_data,
 231                       hb_codepoint_t glyph,
 232                       char *name, unsigned int size,
 233                       void *user_data HB_UNUSED)
 234 {
 235   FT_Face ft_face = (FT_Face) font_data;
 236
 237   hb_bool_t ret = !FT_Get_Glyph_Name (ft_face, glyph, name, size);
 238   if (ret && (size && !*name))
 239     ret = false;
 240
 241   return ret;
 242 }
 243
 244 static hb_bool_t
 245 hb_ft_get_glyph_from_name (hb_font_t *font HB_UNUSED,
 246                            void *font_data,
 247                            const char *name, int len, /* -1 means nul-terminated */
 248                            hb_codepoint_t *glyph,
 249                            void *user_data HB_UNUSED)
 250 {
 251   FT_Face ft_face = (FT_Face) font_data;
 252
 253   if (len < 0)
 254     *glyph = FT_Get_Name_Index (ft_face, (FT_String *) name);
 255   else {
 256     /* Make a nul-terminated version. */
 257     char buf[128];
 258     len = MIN (len, (int) sizeof (buf) - 1);
 259     strncpy (buf, name, len);
 260     buf[len] = '\0';
 261     *glyph = FT_Get_Name_Index (ft_face, buf);
 262   }
 263
 264   return *glyph != 0;
 265 }
 266
 267
 268 static hb_font_funcs_t *
 269 _hb_ft_get_font_funcs (void)
 270 {
 271   static const hb_font_funcs_t ft_ffuncs = {
 272     HB_OBJECT_HEADER_STATIC,
 273
 274     true, /* immutable */
 275
 276     {
 277 #define HB_FONT_FUNC_IMPLEMENT(name) hb_ft_get_##name,
 278       HB_FONT_FUNCS_IMPLEMENT_CALLBACKS
 279 #undef HB_FONT_FUNC_IMPLEMENT
 280     }
 281   };
 282
 283   return const_cast<hb_font_funcs_t *> (&ft_ffuncs);
 284 }
 285
 286
 287 static hb_blob_t *
 288 reference_table  (hb_face_t *face HB_UNUSED, hb_tag_t tag, void *user_data)
 289 {
 290   FT_Face ft_face = (FT_Face) user_data;
 291   FT_Byte *buffer;
 292   FT_ULong  length = 0;
 293   FT_Error error;
 294
 295   /* Note: FreeType like HarfBuzz uses the NONE tag for fetching the entire blob */
 296
 297   error = FT_Load_Sfnt_Table (ft_face, tag, 0, NULL, &length);
 298   if (error)
 299     return NULL;
 300
 301   buffer = (FT_Byte *) malloc (length);
 302   if (buffer == NULL)
 303     return NULL;
 304
 305   error = FT_Load_Sfnt_Table (ft_face, tag, 0, buffer, &length);
 306   if (error)
 307     return NULL;
 308
 309   return hb_blob_create ((const char *) buffer, length,
 310                          HB_MEMORY_MODE_WRITABLE,
 311                          buffer, free);
 312 }
 313
 314
 315 hb_face_t *
 316 hb_ft_face_create (FT_Face           ft_face,
 317                    hb_destroy_func_t destroy)
 318 {
 319   hb_face_t *face;
 320
 321   if (ft_face->stream->read == NULL) {
 322     hb_blob_t *blob;
 323
 324     blob = hb_blob_create ((const char *) ft_face->stream->base,
 325                            (unsigned int) ft_face->stream->size,
 326                            /* TODO: We assume that it's mmap()'ed, but FreeType code
 327                             * suggests that there are cases we reach here but font is
 328                             * not mmapped.  For example, when mmap() fails.  No idea
 329                             * how to deal with it better here. */
 330                            HB_MEMORY_MODE_READONLY_MAY_MAKE_WRITABLE,
 331                            ft_face, destroy);
 332     face = hb_face_create (blob, ft_face->face_index);
 333     hb_blob_destroy (blob);
 334   } else {
 335     face = hb_face_create_for_tables (reference_table, ft_face, destroy);
 336   }
 337
 338   hb_face_set_index (face, ft_face->face_index);
 339   hb_face_set_upem (face, ft_face->units_per_EM);
 340
 341   return face;
 342 }
 343
 344 static void
 345 hb_ft_face_finalize (FT_Face ft_face)
 346 {
 347   hb_face_destroy ((hb_face_t *) ft_face->generic.data);
 348 }
 349
 350 hb_face_t *
 351 hb_ft_face_create_cached (FT_Face ft_face)
 352 {
 353   if (unlikely (!ft_face->generic.data || ft_face->generic.finalizer != (FT_Generic_Finalizer) hb_ft_face_finalize))
 354   {
 355     if (ft_face->generic.finalizer)
 356       ft_face->generic.finalizer (ft_face);
 357
 358     ft_face->generic.data = hb_ft_face_create (ft_face, NULL);
 359     ft_face->generic.finalizer = (FT_Generic_Finalizer) hb_ft_face_finalize;
 360   }
 361
 362   return hb_face_reference ((hb_face_t *) ft_face->generic.data);
 363 }
 364
 365 static void
 366 _do_nothing (void)
 367 {
 368 }
 369
 370
 371 hb_font_t *
 372 hb_ft_font_create (FT_Face           ft_face,
 373                    hb_destroy_func_t destroy)
 374 {
 375   hb_font_t *font;
 376   hb_face_t *face;
 377
 378   face = hb_ft_face_create (ft_face, destroy);
 379   font = hb_font_create (face);
 380   hb_face_destroy (face);
 381   hb_font_set_funcs (font,
 382                      _hb_ft_get_font_funcs (),
 383                      ft_face, (hb_destroy_func_t) _do_nothing);
 384   hb_font_set_scale (font,
 385                      ((uint64_t) ft_face->size->metrics.x_scale * (uint64_t) ft_face->units_per_EM) >> 16,
 386                      ((uint64_t) ft_face->size->metrics.y_scale * (uint64_t) ft_face->units_per_EM) >> 16);
 387   hb_font_set_ppem (font,
 388                     ft_face->size->metrics.x_ppem,
 389                     ft_face->size->metrics.y_ppem);
 390
 391   return font;
 392 }
 393
 394
 395 /* Thread-safe, lock-free, FT_Library */
 396
 397 static FT_Library ft_library;
 398
 399 static inline
 400 void free_ft_library (void)
 401 {
 402   FT_Done_FreeType (ft_library);
 403 }
 404
 405 static FT_Library
 406 get_ft_library (void)
 407 {
 408 retry:
 409   FT_Library library = (FT_Library) hb_atomic_ptr_get (&ft_library);
 410
 411   if (unlikely (!library))
 412   {
 413     /* Not found; allocate one. */
 414     if (FT_Init_FreeType (&library))
 415       return NULL;
 416
 417     if (!hb_atomic_ptr_cmpexch (&ft_library, NULL, library)) {
 418       FT_Done_FreeType (library);
 419       goto retry;
 420     }
 421
 422 #ifdef HAVE_ATEXIT
 423     atexit (free_ft_library); /* First person registers atexit() callback. */
 424 #endif
 425   }
 426
 427   return library;
 428 }
 429
 430 static void
 431 _release_blob (FT_Face ft_face)
 432 {
 433   hb_blob_destroy ((hb_blob_t *) ft_face->generic.data);
 434 }
 435
 436 void
 437 hb_ft_font_set_funcs (hb_font_t *font)
 438 {
 439   hb_blob_t *blob = hb_face_reference_blob (font->face);
 440   unsigned int blob_length;
 441   const char *blob_data = hb_blob_get_data (blob, &blob_length);
 442   if (unlikely (!blob_length))
 443     DEBUG_MSG (FT, font, "Font face has empty blob");
 444
 445   FT_Face ft_face = NULL;
 446   FT_Error err = FT_New_Memory_Face (get_ft_library (),
 447                                      (const FT_Byte *) blob_data,
 448                                      blob_length,
 449                                      hb_face_get_index (font->face),
 450                                      &ft_face);
 451
 452   if (unlikely (err)) {
 453     hb_blob_destroy (blob);
 454     DEBUG_MSG (FT, font, "Font face FT_New_Memory_Face() failed");
 455     return;
 456   }
 457
 458   FT_Select_Charmap (ft_face, FT_ENCODING_UNICODE);
 459
 460   assert (font->y_scale >= 0);
 461   FT_Set_Char_Size (ft_face,
 462                     font->x_scale, font->y_scale,
 463                     0, 0);
 464 #if 0
 465                     font->x_ppem * 72 * 64 / font->x_scale,
 466                     font->y_ppem * 72 * 64 / font->y_scale);
 467 #endif
 468
 469   ft_face->generic.data = blob;
 470   ft_face->generic.finalizer = (FT_Generic_Finalizer) _release_blob;
 471
 472   hb_font_set_funcs (font,
 473                      _hb_ft_get_font_funcs (),
 474                      ft_face,
 475                      (hb_destroy_func_t) FT_Done_Face);
 476 }
 477
 478 FT_Face
 479 hb_ft_font_get_face (hb_font_t *font)
 480 {
 481   if (font->destroy == (hb_destroy_func_t) FT_Done_Face ||
 482       font->destroy == (hb_destroy_func_t) _do_nothing)
 483     return (FT_Face) font->user_data;
 484
 485   return NULL;
 486 }