tor-browser

The Tor Browser
git clone https://git.dasho.dev/tor-browser.git
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hb-kern.hh (3608B)

      1 /*
      2 * Copyright © 2017  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 #ifndef HB_KERN_HH
     28 #define HB_KERN_HH
     29 
     30 #include "hb-open-type.hh"
     31 #include "hb-aat-layout-common.hh"
     32 #include "hb-ot-layout-gpos-table.hh"
     33 
     34 
     35 namespace OT {
     36 
     37 
     38 template <typename Driver>
     39 struct hb_kern_machine_t
     40 {
     41  hb_kern_machine_t (const Driver &driver_,
     42 	     bool crossStream_ = false) :
     43 	       driver (driver_),
     44 	       crossStream (crossStream_) {}
     45 
     46  HB_NO_SANITIZE_SIGNED_INTEGER_OVERFLOW
     47  void kern (hb_font_t   *font,
     48      hb_buffer_t *buffer,
     49      hb_mask_t    kern_mask,
     50      bool         scale = true) const
     51  {
     52    if (!buffer->message (font, "start kern"))
     53      return;
     54 
     55    buffer->unsafe_to_concat ();
     56    OT::hb_ot_apply_context_t c (1, font, buffer, hb_blob_get_empty ());
     57    c.set_lookup_mask (kern_mask);
     58    c.set_lookup_props (OT::LookupFlag::IgnoreMarks);
     59    auto &skippy_iter = c.iter_input;
     60 
     61    bool horizontal = HB_DIRECTION_IS_HORIZONTAL (buffer->props.direction);
     62    unsigned int count = buffer->len;
     63    hb_glyph_info_t *info = buffer->info;
     64    hb_glyph_position_t *pos = buffer->pos;
     65    for (unsigned int idx = 0; idx < count;)
     66    {
     67      if (!(info[idx].mask & kern_mask))
     68      {
     69 idx++;
     70 continue;
     71      }
     72 
     73      skippy_iter.reset_fast (idx);
     74      unsigned unsafe_to;
     75      if (!skippy_iter.next (&unsafe_to))
     76      {
     77 idx++;
     78 continue;
     79      }
     80 
     81      unsigned int i = idx;
     82      unsigned int j = skippy_iter.idx;
     83 
     84      hb_position_t kern = driver.get_kerning (info[i].codepoint,
     85 				       info[j].codepoint);
     86 
     87 
     88      if (likely (!kern))
     89 goto skip;
     90 
     91      if (horizontal)
     92      {
     93 if (scale)
     94   kern = font->em_scale_x (kern);
     95 if (crossStream)
     96 {
     97   pos[j].y_offset = kern;
     98   buffer->scratch_flags |= HB_BUFFER_SCRATCH_FLAG_HAS_GPOS_ATTACHMENT;
     99 }
    100 else
    101 {
    102   hb_position_t kern1 = kern >> 1;
    103   hb_position_t kern2 = kern - kern1;
    104   pos[i].x_advance += kern1;
    105   pos[j].x_advance += kern2;
    106   pos[j].x_offset += kern2;
    107 }
    108      }
    109      else
    110      {
    111 if (scale)
    112   kern = font->em_scale_y (kern);
    113 if (crossStream)
    114 {
    115   pos[j].x_offset = kern;
    116   buffer->scratch_flags |= HB_BUFFER_SCRATCH_FLAG_HAS_GPOS_ATTACHMENT;
    117 }
    118 else
    119 {
    120   hb_position_t kern1 = kern >> 1;
    121   hb_position_t kern2 = kern - kern1;
    122   pos[i].y_advance += kern1;
    123   pos[j].y_advance += kern2;
    124   pos[j].y_offset += kern2;
    125 }
    126      }
    127 
    128      buffer->unsafe_to_break (i, j + 1);
    129 
    130    skip:
    131      idx = skippy_iter.idx;
    132    }
    133 
    134    (void) buffer->message (font, "end kern");
    135  }
    136 
    137  const Driver &driver;
    138  bool crossStream;
    139 };
    140 
    141 
    142 } /* namespace OT */
    143 
    144 
    145 #endif /* HB_KERN_HH */