1 /*

     2  * Copyright © 2009  Red Hat, Inc.

     3  * Copyright © 2009  Keith Stribley

     4  * Copyright © 2015  Google, Inc.

     5  *

     6  *  This is part of HarfBuzz, a text shaping library.

     7  *

     8  * Permission is hereby granted, without written agreement and without

     9  * license or royalty fees, to use, copy, modify, and distribute this

    10  * software and its documentation for any purpose, provided that the

    11  * above copyright notice and the following two paragraphs appear in

    12  * all copies of this software.

    13  *

    14  * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR

    15  * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES

    16  * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN

    17  * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH

    18  * DAMAGE.

    19  *

    20  * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,

    21  * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND

    22  * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS

    23  * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO

    24  * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.

    25  *

    26  * Red Hat Author(s): Behdad Esfahbod

    27  * Google Author(s): Behdad Esfahbod

    28  */

    29 

    30 #include "hb-private.hh"

    31 

    32 #include "hb-ft.h"

    33 

    34 #include "hb-font-private.hh"

    35 

    36 #include FT_ADVANCES_H

    37 #include FT_TRUETYPE_TABLES_H

    38 

    39 

    40 

    41 #ifndef HB_DEBUG_FT

    42 #define HB_DEBUG_FT (HB_DEBUG+0)

    43 #endif

    44 

    45 

    46 /* TODO:

    47  *

    48  * In general, this file does a fine job of what it's supposed to do.

    49  * There are, however, things that need more work:

    50  *

    51  *   - I remember seeing FT_Get_Advance() without the NO_HINTING flag to be buggy.

    52  *     Have not investigated.

    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 as load_flags.  Would be much better to use NO_SCALE, and scale

    59  *     ourselves, like we do in uniscribe, etc.

    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 struct hb_ft_font_t

    70 {

    71   FT_Face ft_face;

    72   int load_flags;

    73   bool unref; /* Whether to destroy ft_face when done. */

    74 };

    75 

    76 static hb_ft_font_t *

    77 _hb_ft_font_create (FT_Face ft_face, bool unref)

    78 {

    79   hb_ft_font_t *ft_font = (hb_ft_font_t *) calloc (1, sizeof (hb_ft_font_t));

    80 

    81   if (unlikely (!ft_font))

    82     return NULL;

    83 

    84   ft_font->ft_face = ft_face;

    85   ft_font->unref = unref;

    86 

    87   ft_font->load_flags = FT_LOAD_DEFAULT | FT_LOAD_NO_HINTING;

    88 

    89   return ft_font;

    90 }

    91 

    92 static void

    93 _hb_ft_font_destroy (hb_ft_font_t *ft_font)

    94 {

    95   if (ft_font->unref)

    96     FT_Done_Face (ft_font->ft_face);

    97 

    98   free (ft_font);

    99 }

   100 

   101 /**

   102  * hb_ft_font_set_load_flags:

   103  * @font:

   104  * @load_flags:

   105  *

   106  *

   107  *

   108  * Since: 1.0.5

   109  **/

   110 void

   111 hb_ft_font_set_load_flags (hb_font_t *font, int load_flags)

   112 {

   113   if (font->immutable)

   114     return;

   115 

   116   if (font->destroy != (hb_destroy_func_t) _hb_ft_font_destroy)

   117     return;

   118 

   119   hb_ft_font_t *ft_font = (hb_ft_font_t *) font->user_data;

   120 

   121   ft_font->load_flags = load_flags;

   122 }

   123 

   124 /**

   125  * hb_ft_font_get_load_flags:

   126  * @font:

   127  *

   128  *

   129  *

   130  * Return value:

   131  * Since: 1.0.5

   132  **/

   133 int

   134 hb_ft_font_get_load_flags (hb_font_t *font)

   135 {

   136   if (font->destroy != (hb_destroy_func_t) _hb_ft_font_destroy)

   137     return 0;

   138 

   139   const hb_ft_font_t *ft_font = (const hb_ft_font_t *) font->user_data;

   140 

   141   return ft_font->load_flags;

   142 }

   143 

   144 FT_Face

   145 hb_ft_font_get_face (hb_font_t *font)

   146 {

   147   if (font->destroy != (hb_destroy_func_t) _hb_ft_font_destroy)

   148     return NULL;

   149 

   150   const hb_ft_font_t *ft_font = (const hb_ft_font_t *) font->user_data;

   151 

   152   return ft_font->ft_face;

   153 }

   154 

   155 

   156 

   157 static hb_bool_t

   158 hb_ft_get_glyph (hb_font_t *font HB_UNUSED,

   159                  void *font_data,

   160                  hb_codepoint_t unicode,

   161                  hb_codepoint_t variation_selector,

   162                  hb_codepoint_t *glyph,

   163                  void *user_data HB_UNUSED)

   164 

   165 {

   166   const hb_ft_font_t *ft_font = (const hb_ft_font_t *) font_data;

   167   unsigned int g;

   168 

   169   if (likely (!variation_selector))

   170     g = FT_Get_Char_Index (ft_font->ft_face, unicode);

   171   else

   172     g = FT_Face_GetCharVariantIndex (ft_font->ft_face, unicode, variation_selector);

   173 

   174   if (unlikely (!g))

   175     return false;

   176 

   177   *glyph = g;

   178   return true;

   179 }

   180 

   181 static hb_position_t

   182 hb_ft_get_glyph_h_advance (hb_font_t *font HB_UNUSED,

   183                            void *font_data,

   184                            hb_codepoint_t glyph,

   185                            void *user_data HB_UNUSED)

   186 {

   187   const hb_ft_font_t *ft_font = (const hb_ft_font_t *) font_data;

   188   FT_Fixed v;

   189 

   190   if (unlikely (FT_Get_Advance (ft_font->ft_face, glyph, ft_font->load_flags, &v)))

   191     return 0;

   192 

   193   if (font->x_scale < 0)

   194     v = -v;

   195 

   196   return (v + (1<<9)) >> 10;

   197 }

   198 

   199 static hb_position_t

   200 hb_ft_get_glyph_v_advance (hb_font_t *font HB_UNUSED,

   201                            void *font_data,

   202                            hb_codepoint_t glyph,

   203                            void *user_data HB_UNUSED)

   204 {

   205   const hb_ft_font_t *ft_font = (const hb_ft_font_t *) font_data;

   206   FT_Fixed v;

   207 

   208   if (unlikely (FT_Get_Advance (ft_font->ft_face, glyph, ft_font->load_flags | FT_LOAD_VERTICAL_LAYOUT, &v)))

   209     return 0;

   210 

   211   if (font->y_scale < 0)

   212     v = -v;

   213 

   214   /* Note: FreeType's vertical metrics grows downward while other FreeType coordinates

   215    * have a Y growing upward.  Hence the extra negation. */

   216   return (-v + (1<<9)) >> 10;

   217 }

   218 

   219 static hb_bool_t

   220 hb_ft_get_glyph_h_origin (hb_font_t *font HB_UNUSED,

   221                           void *font_data HB_UNUSED,

   222                           hb_codepoint_t glyph HB_UNUSED,

   223                           hb_position_t *x HB_UNUSED,

   224                           hb_position_t *y HB_UNUSED,

   225                           void *user_data HB_UNUSED)

   226 {

   227   /* We always work in the horizontal coordinates. */

   228   return true;

   229 }

   230 

   231 static hb_bool_t

   232 hb_ft_get_glyph_v_origin (hb_font_t *font HB_UNUSED,

   233                           void *font_data,

   234                           hb_codepoint_t glyph,

   235                           hb_position_t *x,

   236                           hb_position_t *y,

   237                           void *user_data HB_UNUSED)

   238 {

   239   const hb_ft_font_t *ft_font = (const hb_ft_font_t *) font_data;

   240   FT_Face ft_face = ft_font->ft_face;

   241 

   242   if (unlikely (FT_Load_Glyph (ft_face, glyph, ft_font->load_flags)))

   243     return false;

   244 

   245   /* Note: FreeType's vertical metrics grows downward while other FreeType coordinates

   246    * have a Y growing upward.  Hence the extra negation. */

   247   *x = ft_face->glyph->metrics.horiBearingX -   ft_face->glyph->metrics.vertBearingX;

   248   *y = ft_face->glyph->metrics.horiBearingY - (-ft_face->glyph->metrics.vertBearingY);

   249 

   250   if (font->x_scale < 0)

   251     *x = -*x;

   252   if (font->y_scale < 0)

   253     *y = -*y;

   254 

   255   return true;

   256 }

   257 

   258 static hb_position_t

   259 hb_ft_get_glyph_h_kerning (hb_font_t *font,

   260                            void *font_data,

   261                            hb_codepoint_t left_glyph,

   262                            hb_codepoint_t right_glyph,

   263                            void *user_data HB_UNUSED)

   264 {

   265   const hb_ft_font_t *ft_font = (const hb_ft_font_t *) font_data;

   266   FT_Vector kerningv;

   267 

   268   FT_Kerning_Mode mode = font->x_ppem ? FT_KERNING_DEFAULT : FT_KERNING_UNFITTED;

   269   if (FT_Get_Kerning (ft_font->ft_face, left_glyph, right_glyph, mode, &kerningv))

   270     return 0;

   271 

   272   return kerningv.x;

   273 }

   274 

   275 static hb_position_t

   276 hb_ft_get_glyph_v_kerning (hb_font_t *font HB_UNUSED,

   277                            void *font_data HB_UNUSED,

   278                            hb_codepoint_t top_glyph HB_UNUSED,

   279                            hb_codepoint_t bottom_glyph HB_UNUSED,

   280                            void *user_data HB_UNUSED)

   281 {

   282   /* FreeType API doesn't support vertical kerning */

   283   return 0;

   284 }

   285 

   286 static hb_bool_t

   287 hb_ft_get_glyph_extents (hb_font_t *font HB_UNUSED,

   288                          void *font_data,

   289                          hb_codepoint_t glyph,

   290                          hb_glyph_extents_t *extents,

   291                          void *user_data HB_UNUSED)

   292 {

   293   const hb_ft_font_t *ft_font = (const hb_ft_font_t *) font_data;

   294   FT_Face ft_face = ft_font->ft_face;

   295 

   296   if (unlikely (FT_Load_Glyph (ft_face, glyph, ft_font->load_flags)))

   297     return false;

   298 

   299   extents->x_bearing = ft_face->glyph->metrics.horiBearingX;

   300   extents->y_bearing = ft_face->glyph->metrics.horiBearingY;

   301   extents->width = ft_face->glyph->metrics.width;

   302   extents->height = -ft_face->glyph->metrics.height;

   303   return true;

   304 }

   305 

   306 static hb_bool_t

   307 hb_ft_get_glyph_contour_point (hb_font_t *font HB_UNUSED,

   308                                void *font_data,

   309                                hb_codepoint_t glyph,

   310                                unsigned int point_index,

   311                                hb_position_t *x,

   312                                hb_position_t *y,

   313                                void *user_data HB_UNUSED)

   314 {

   315   const hb_ft_font_t *ft_font = (const hb_ft_font_t *) font_data;

   316   FT_Face ft_face = ft_font->ft_face;

   317 

   318   if (unlikely (FT_Load_Glyph (ft_face, glyph, ft_font->load_flags)))

   319       return false;

   320 

   321   if (unlikely (ft_face->glyph->format != FT_GLYPH_FORMAT_OUTLINE))

   322       return false;

   323 

   324   if (unlikely (point_index >= (unsigned int) ft_face->glyph->outline.n_points))

   325       return false;

   326 

   327   *x = ft_face->glyph->outline.points[point_index].x;

   328   *y = ft_face->glyph->outline.points[point_index].y;

   329 

   330   return true;

   331 }

   332 

   333 static hb_bool_t

   334 hb_ft_get_glyph_name (hb_font_t *font HB_UNUSED,

   335                       void *font_data,

   336                       hb_codepoint_t glyph,

   337                       char *name, unsigned int size,

   338                       void *user_data HB_UNUSED)

   339 {

   340   const hb_ft_font_t *ft_font = (const hb_ft_font_t *) font_data;

   341 

   342   hb_bool_t ret = !FT_Get_Glyph_Name (ft_font->ft_face, glyph, name, size);

   343   if (ret && (size && !*name))

   344     ret = false;

   345 

   346   return ret;

   347 }

   348 

   349 static hb_bool_t

   350 hb_ft_get_glyph_from_name (hb_font_t *font HB_UNUSED,

   351                            void *font_data,

   352                            const char *name, int len, /* -1 means nul-terminated */

   353                            hb_codepoint_t *glyph,

   354                            void *user_data HB_UNUSED)

   355 {

   356   const hb_ft_font_t *ft_font = (const hb_ft_font_t *) font_data;

   357   FT_Face ft_face = ft_font->ft_face;

   358 

   359   if (len < 0)

   360     *glyph = FT_Get_Name_Index (ft_face, (FT_String *) name);

   361   else {

   362     /* Make a nul-terminated version. */

   363     char buf[128];

   364     len = MIN (len, (int) sizeof (buf) - 1);

   365     strncpy (buf, name, len);

   366     buf[len] = '\0';

   367     *glyph = FT_Get_Name_Index (ft_face, buf);

   368   }

   369 

   370   if (*glyph == 0)

   371   {

   372     /* Check whether the given name was actually the name of glyph 0. */

   373     char buf[128];

   374     if (!FT_Get_Glyph_Name(ft_face, 0, buf, sizeof (buf)) &&

   375         len < 0 ? !strcmp (buf, name) : !strncmp (buf, name, len))

   376       return true;

   377   }

   378 

   379   return *glyph != 0;

   380 }

   381 

   382 

   383 static void

   384 _hb_ft_font_set_funcs (hb_font_t *font, FT_Face ft_face, bool unref)

   385 {

   386   static const hb_font_funcs_t ft_ffuncs = {

   387     HB_OBJECT_HEADER_STATIC,

   388 

   389     true, /* immutable */

   390 

   391     {

   392 #define HB_FONT_FUNC_IMPLEMENT(name) hb_ft_get_##name,

   393       HB_FONT_FUNCS_IMPLEMENT_CALLBACKS

   394 #undef HB_FONT_FUNC_IMPLEMENT

   395     }

   396   };

   397 

   398   hb_font_set_funcs (font,

   399                      const_cast<hb_font_funcs_t *> (&ft_ffuncs),

   400                      _hb_ft_font_create (ft_face, unref),

   401                      (hb_destroy_func_t) _hb_ft_font_destroy);

   402 }

   403 

   404 

   405 static hb_blob_t *

   406 reference_table  (hb_face_t *face HB_UNUSED, hb_tag_t tag, void *user_data)

   407 {

   408   FT_Face ft_face = (FT_Face) user_data;

   409   FT_Byte *buffer;

   410   FT_ULong  length = 0;

   411   FT_Error error;

   412 

   413   /* Note: FreeType like HarfBuzz uses the NONE tag for fetching the entire blob */

   414 

   415   error = FT_Load_Sfnt_Table (ft_face, tag, 0, NULL, &length);

   416   if (error)

   417     return NULL;

   418 

   419   buffer = (FT_Byte *) malloc (length);

   420   if (buffer == NULL)

   421     return NULL;

   422 

   423   error = FT_Load_Sfnt_Table (ft_face, tag, 0, buffer, &length);

   424   if (error)

   425     return NULL;

   426 

   427   return hb_blob_create ((const char *) buffer, length,

   428                          HB_MEMORY_MODE_WRITABLE,

   429                          buffer, free);

   430 }

   431 

   432 /**

   433  * hb_ft_face_create:

   434  * @ft_face: (destroy destroy) (scope notified):

   435  * @destroy:

   436  *

   437  *

   438  *

   439  * Return value: (transfer full):

   440  * Since: 0.9.2

   441  **/

   442 hb_face_t *

   443 hb_ft_face_create (FT_Face           ft_face,

   444                    hb_destroy_func_t destroy)

   445 {

   446   hb_face_t *face;

   447 

   448   if (ft_face->stream->read == NULL) {

   449     hb_blob_t *blob;

   450 

   451     blob = hb_blob_create ((const char *) ft_face->stream->base,

   452                            (unsigned int) ft_face->stream->size,

   453                            HB_MEMORY_MODE_READONLY,

   454                            ft_face, destroy);

   455     face = hb_face_create (blob, ft_face->face_index);

   456     hb_blob_destroy (blob);

   457   } else {

   458     face = hb_face_create_for_tables (reference_table, ft_face, destroy);

   459   }

   460 

   461   hb_face_set_index (face, ft_face->face_index);

   462   hb_face_set_upem (face, ft_face->units_per_EM);

   463 

   464   return face;

   465 }

   466 

   467 /**

   468  * hb_ft_face_create_referenced:

   469  * @ft_face:

   470  *

   471  *

   472  *

   473  * Return value: (transfer full):

   474  * Since: 0.9.38

   475  **/

   476 hb_face_t *

   477 hb_ft_face_create_referenced (FT_Face ft_face)

   478 {

   479   FT_Reference_Face (ft_face);

   480   return hb_ft_face_create (ft_face, (hb_destroy_func_t) FT_Done_Face);

   481 }

   482 

   483 static void

   484 hb_ft_face_finalize (FT_Face ft_face)

   485 {

   486   hb_face_destroy ((hb_face_t *) ft_face->generic.data);

   487 }

   488 

   489 /**

   490  * hb_ft_face_create_cached:

   491  * @ft_face:

   492  *

   493  *

   494  *

   495  * Return value: (transfer full):

   496  * Since: 0.9.2

   497  **/

   498 hb_face_t *

   499 hb_ft_face_create_cached (FT_Face ft_face)

   500 {

   501   if (unlikely (!ft_face->generic.data || ft_face->generic.finalizer != (FT_Generic_Finalizer) hb_ft_face_finalize))

   502   {

   503     if (ft_face->generic.finalizer)

   504       ft_face->generic.finalizer (ft_face);

   505 

   506     ft_face->generic.data = hb_ft_face_create (ft_face, NULL);

   507     ft_face->generic.finalizer = (FT_Generic_Finalizer) hb_ft_face_finalize;

   508   }

   509 

   510   return hb_face_reference ((hb_face_t *) ft_face->generic.data);

   511 }

   512 

   513 

   514 /**

   515  * hb_ft_font_create:

   516  * @ft_face: (destroy destroy) (scope notified):

   517  * @destroy:

   518  *

   519  *

   520  *

   521  * Return value: (transfer full):

   522  * Since: 0.9.2

   523  **/

   524 hb_font_t *

   525 hb_ft_font_create (FT_Face           ft_face,

   526                    hb_destroy_func_t destroy)

   527 {

   528   hb_font_t *font;

   529   hb_face_t *face;

   530 

   531   face = hb_ft_face_create (ft_face, destroy);

   532   font = hb_font_create (face);

   533   hb_face_destroy (face);

   534   _hb_ft_font_set_funcs (font, ft_face, false);

   535   hb_font_set_scale (font,

   536                      (int) (((uint64_t) ft_face->size->metrics.x_scale * (uint64_t) ft_face->units_per_EM + (1<<15)) >> 16),

   537                      (int) (((uint64_t) ft_face->size->metrics.y_scale * (uint64_t) ft_face->units_per_EM + (1<<15)) >> 16));

   538 #if 0 /* hb-ft works in no-hinting model */

   539   hb_font_set_ppem (font,

   540                     ft_face->size->metrics.x_ppem,

   541                     ft_face->size->metrics.y_ppem);

   542 #endif

   543 

   544   return font;

   545 }

   546 

   547 /**

   548  * hb_ft_font_create_referenced:

   549  * @ft_face:

   550  *

   551  *

   552  *

   553  * Return value: (transfer full):

   554  * Since: 0.9.38

   555  **/

   556 hb_font_t *

   557 hb_ft_font_create_referenced (FT_Face ft_face)

   558 {

   559   FT_Reference_Face (ft_face);

   560   return hb_ft_font_create (ft_face, (hb_destroy_func_t) FT_Done_Face);

   561 }

   562 

   563 

   564 /* Thread-safe, lock-free, FT_Library */

   565 

   566 static FT_Library ft_library;

   567 

   568 #ifdef HB_USE_ATEXIT

   569 static

   570 void free_ft_library (void)

   571 {

   572   FT_Done_FreeType (ft_library);

   573 }

   574 #endif

   575 

   576 static FT_Library

   577 get_ft_library (void)

   578 {

   579 retry:

   580   FT_Library library = (FT_Library) hb_atomic_ptr_get (&ft_library);

   581 

   582   if (unlikely (!library))

   583   {

   584     /* Not found; allocate one. */

   585     if (FT_Init_FreeType (&library))

   586       return NULL;

   587 

   588     if (!hb_atomic_ptr_cmpexch (&ft_library, NULL, library)) {

   589       FT_Done_FreeType (library);

   590       goto retry;

   591     }

   592 

   593 #ifdef HB_USE_ATEXIT

   594     atexit (free_ft_library); /* First person registers atexit() callback. */

   595 #endif

   596   }

   597 

   598   return library;

   599 }

   600 

   601 static void

   602 _release_blob (FT_Face ft_face)

   603 {

   604   hb_blob_destroy ((hb_blob_t *) ft_face->generic.data);

   605 }

   606 

   607 void

   608 hb_ft_font_set_funcs (hb_font_t *font)

   609 {

   610   hb_blob_t *blob = hb_face_reference_blob (font->face);

   611   unsigned int blob_length;

   612   const char *blob_data = hb_blob_get_data (blob, &blob_length);

   613   if (unlikely (!blob_length))

   614     DEBUG_MSG (FT, font, "Font face has empty blob");

   615 

   616   FT_Face ft_face = NULL;

   617   FT_Error err = FT_New_Memory_Face (get_ft_library (),

   618                                      (const FT_Byte *) blob_data,

   619                                      blob_length,

   620                                      hb_face_get_index (font->face),

   621                                      &ft_face);

   622 

   623   if (unlikely (err)) {

   624     hb_blob_destroy (blob);

   625     DEBUG_MSG (FT, font, "Font face FT_New_Memory_Face() failed");

   626     return;

   627   }

   628 

   629   FT_Select_Charmap (ft_face, FT_ENCODING_UNICODE);

   630 

   631   FT_Set_Char_Size (ft_face,

   632                     abs (font->x_scale), abs (font->y_scale),

   633                     0, 0);

   634 #if 0

   635                     font->x_ppem * 72 * 64 / font->x_scale,

   636                     font->y_ppem * 72 * 64 / font->y_scale);

   637 #endif

   638   if (font->x_scale < 0 || font->y_scale < 0)

   639   {

   640     FT_Matrix matrix = { font->x_scale < 0 ? -1 : +1, 0,

   641                           0, font->y_scale < 0 ? -1 : +1};

   642     FT_Set_Transform (ft_face, &matrix, NULL);

   643   }

   644 

   645   ft_face->generic.data = blob;

   646   ft_face->generic.finalizer = (FT_Generic_Finalizer) _release_blob;

   647 

   648   _hb_ft_font_set_funcs (font, ft_face, true);

   649   hb_ft_font_set_load_flags (font, FT_LOAD_DEFAULT | FT_LOAD_NO_HINTING);

   650 }