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      1 /*
      2  * Copyright  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
     25  */
     26 
     27 #include <stdlib.h>
     28 #include <stdio.h>
     29 
     30 #include "hb-fc.h"
     31 
     32 static hb_bool_t
     33 hb_fc_get_glyph (hb_font_t *font /*HB_UNUSED*/,
     34 		 void *font_data,
     35 		 hb_codepoint_t unicode,
     36 		 hb_codepoint_t variation_selector,
     37 		 hb_codepoint_t *glyph,
     38 		 void *user_data /*HB_UNUSED*/)
     39 
     40 {
     41   FcCharSet *cs = (FcCharSet *) font_data;
     42 
     43   if (variation_selector)
     44   {
     45     /* Fontconfig doesn't cache cmap-14 info.  However:
     46      * 1. If the font maps the variation_selector, assume it's
     47      *    supported,
     48      * 2. If the font doesn't map it, still say it's supported,
     49      *    but return 0.  This way, the caller will see the zero
     50      *    and reject.  If we return unsupported here, then the
     51      *    variation selector will be hidden and ignored.
     52      */
     53     if (FcCharSetHasChar (cs, unicode) &&
     54 	FcCharSetHasChar (cs, variation_selector))
     55     {
     56       unsigned int var_num = 0;
     57       if (variation_selector - 0xFE00u < 16)
     58         var_num = variation_selector - 0xFE00 + 1;
     59       else if (variation_selector - 0xE0100u < (256 - 16))
     60         var_num = variation_selector - 0xE0100 + 17;
     61       *glyph = (var_num << 21) | unicode;
     62     }
     63     else
     64     {
     65       *glyph = 0;
     66     }
     67     return true;
     68   }
     69 
     70   *glyph = FcCharSetHasChar (cs, unicode) ? unicode : 0;
     71   return *glyph != 0;
     72 }
     73 
     74 static hb_font_funcs_t *
     75 _hb_fc_get_font_funcs (void)
     76 {
     77   static const hb_font_funcs_t *fc_ffuncs;
     78 
     79   const hb_font_funcs_t *ffuncs;
     80 
     81   if (!(ffuncs = fc_ffuncs))
     82   {
     83     hb_font_funcs_t *newfuncs = hb_font_funcs_create ();
     84 
     85     hb_font_funcs_set_glyph_func (newfuncs, hb_fc_get_glyph, NULL, NULL);
     86 
     87     /* XXX MT-unsafe */
     88     if (fc_ffuncs)
     89       hb_font_funcs_destroy (newfuncs);
     90     else
     91       fc_ffuncs = ffuncs = newfuncs;
     92   }
     93 
     94   return const_cast<hb_font_funcs_t *> (fc_ffuncs);
     95 }
     96 
     97 
     98 hb_font_t *
     99 hb_fc_font_create (FcPattern *fcfont)
    100 {
    101   static hb_face_t *face;
    102   hb_font_t *font;
    103 
    104   FcCharSet *cs;
    105   if (FcResultMatch != FcPatternGetCharSet (fcfont, FC_CHARSET, 0, &cs))
    106     return hb_font_get_empty ();
    107 
    108   if (!face) /* XXX MT-unsafe */
    109     face = hb_face_create (hb_blob_get_empty (), 0);
    110 
    111   font = hb_font_create (face);
    112 
    113   hb_font_set_funcs (font,
    114 		     _hb_fc_get_font_funcs (),
    115 		     FcCharSetCopy (cs),
    116 		     (hb_destroy_func_t) FcCharSetDestroy);
    117 
    118   return font;
    119 }
    120 
    121 hb_bool_t
    122 hb_fc_can_render (hb_font_t *font, const char *text)
    123 {
    124   static const char *ot[] = {"ot", NULL};
    125 
    126   hb_buffer_t *buffer = hb_buffer_create ();
    127   hb_buffer_add_utf8 (buffer, text, -1, 0, -1);
    128 
    129   /* XXX Do we need this?  I think Arabic and Hangul shapers are the
    130    * only one that make any use of this.  The Hangul case is not really
    131    * needed, and for Arabic we'll miss a very narrow set of fonts.
    132    * Might be better to force generic shaper perhaps. */
    133   hb_buffer_guess_segment_properties (buffer);
    134 
    135   if (!hb_shape_full (font, buffer, NULL, 0, ot))
    136     abort (); /* hb-ot shaper not enabled? */
    137 
    138   unsigned int len;
    139   hb_glyph_info_t *info = hb_buffer_get_glyph_infos (buffer, &len);
    140   for (unsigned int i = 0; i < len; i++)
    141    {
    142     if (!info[i].codepoint)
    143      {
    144       return false;
    145      }
    146    }
    147 
    148   return true;
    149 }
    150