HarfBuzz text shaping engine http://harfbuzz.github.io/
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/*
* Copyright © 2014 Google, Inc.
*
* This is part of HarfBuzz, a text shaping library.
*
* Permission is hereby granted, without written agreement and without
* license or royalty fees, to use, copy, modify, and distribute this
* software and its documentation for any purpose, provided that the
* above copyright notice and the following two paragraphs appear in
* all copies of this software.
*
* IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
* DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
* ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
* IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
* DAMAGE.
*
* THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
* BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
* FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
* ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
* PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
*
* Google Author(s): Behdad Esfahbod
*/
#include <stdlib.h>
#include <stdio.h>
#include "hb-fc.h"
static hb_bool_t
hb_fc_get_glyph (hb_font_t *font /*HB_UNUSED*/,
void *font_data,
hb_codepoint_t unicode,
hb_codepoint_t variation_selector,
hb_codepoint_t *glyph,
void *user_data /*HB_UNUSED*/)
{
FcCharSet *cs = (FcCharSet *) font_data;
if (variation_selector)
{
/* Fontconfig doesn't cache cmap-14 info. However:
* 1. If the font maps the variation_selector, assume it's
* supported,
* 2. If the font doesn't map it, still say it's supported,
* but return 0. This way, the caller will see the zero
* and reject. If we return unsupported here, then the
* variation selector will be hidden and ignored.
*/
if (FcCharSetHasChar (cs, unicode) &&
FcCharSetHasChar (cs, variation_selector))
{
unsigned int var_num = 0;
if (variation_selector - 0xFE00u < 16)
var_num = variation_selector - 0xFE00 + 1;
else if (variation_selector - 0xE0100u < (256 - 16))
var_num = variation_selector - 0xE0100 + 17;
*glyph = (var_num << 21) | unicode;
}
else
{
*glyph = 0;
}
return true;
}
*glyph = FcCharSetHasChar (cs, unicode) ? unicode : 0;
return *glyph != 0;
}
static hb_font_funcs_t *
_hb_fc_get_font_funcs ()
{
static const hb_font_funcs_t *fc_ffuncs;
if (!fc_ffuncs)
{
hb_font_funcs_t *newfuncs = hb_font_funcs_create ();
hb_font_funcs_set_glyph_func (newfuncs, hb_fc_get_glyph, nullptr, nullptr);
/* XXX MT-unsafe */
if (fc_ffuncs)
hb_font_funcs_destroy (newfuncs);
else
fc_ffuncs = newfuncs;
}
return const_cast<hb_font_funcs_t *> (fc_ffuncs);
}
hb_font_t *
hb_fc_font_create (FcPattern *fcfont)
{
static hb_face_t *face;
hb_font_t *font;
FcCharSet *cs;
if (FcResultMatch != FcPatternGetCharSet (fcfont, FC_CHARSET, 0, &cs))
return hb_font_get_empty ();
if (!face) /* XXX MT-unsafe */
face = hb_face_create (hb_blob_get_empty (), 0);
font = hb_font_create (face);
hb_font_set_funcs (font,
_hb_fc_get_font_funcs (),
FcCharSetCopy (cs),
(hb_destroy_func_t) FcCharSetDestroy);
return font;
}
hb_bool_t
hb_fc_can_render (hb_font_t *font, const char *text)
{
static const char *ot[] = {"ot", nullptr};
hb_buffer_t *buffer = hb_buffer_create ();
hb_buffer_add_utf8 (buffer, text, -1, 0, -1);
/* XXX Do we need this? I think Arabic and Hangul shapers are the
* only one that make any use of this. The Hangul case is not really
* needed, and for Arabic we'll miss a very narrow set of fonts.
* Might be better to force generic shaper perhaps. */
hb_buffer_guess_segment_properties (buffer);
if (!hb_shape_full (font, buffer, nullptr, 0, ot))
abort (); /* hb-ot shaper not enabled? */
unsigned int len;
hb_glyph_info_t *info = hb_buffer_get_glyph_infos (buffer, &len);
for (unsigned int i = 0; i < len; i++)
{
if (!info[i].codepoint)
{
return false;
}
}
return true;
}