summaryrefslogtreecommitdiffstats
path: root/gfx/harfbuzz/src/hb-subset-cff-common.cc
blob: 6e1b6f713d219066111b303c5216969113a4972b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
/*
 * Copyright © 2018 Adobe 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.
 *
 * Adobe Author(s): Michiharu Ariza
 */

#include "hb.hh"

#ifndef HB_NO_SUBSET_CFF

#include "hb-ot-cff-common.hh"
#include "hb-ot-cff2-table.hh"
#include "hb-subset-cff-common.hh"

/* Disable FDSelect format 0 for compatibility with fonttools which doesn't seem choose it.
 * Rarely any/much smaller than format 3 anyway. */
#define CFF_SERIALIZE_FDSELECT_0  0

using namespace CFF;


/* Determine an optimal FDSelect format according to a provided plan.
 *
 * Return value: FDSelect format, size, and ranges for the most compact subset FDSelect
 * along with a font index remapping table
 */

bool
hb_plan_subset_cff_fdselect (const hb_subset_plan_t *plan,
			     unsigned int fdCount,
			     const FDSelect &src, /* IN */
			     unsigned int &subset_fd_count /* OUT */,
			     unsigned int &subset_fdselect_size /* OUT */,
			     unsigned int &subset_fdselect_format /* OUT */,
			     hb_vector_t<code_pair_t> &fdselect_ranges /* OUT */,
			     hb_inc_bimap_t &fdmap /* OUT */)
{
  subset_fd_count = 0;
  subset_fdselect_size = 0;
  subset_fdselect_format = 0;
  unsigned int num_ranges = 0;

  unsigned int subset_num_glyphs = plan->num_output_glyphs ();
  if (subset_num_glyphs == 0)
    return true;

  {
    /* use hb_set to determine the subset of font dicts */
    hb_set_t set;
    hb_codepoint_t prev_fd = CFF_UNDEF_CODE;
    for (hb_codepoint_t i = 0; i < subset_num_glyphs; i++)
    {
      hb_codepoint_t glyph;
      hb_codepoint_t fd;
      if (!plan->old_gid_for_new_gid (i, &glyph))
      {
	/* fonttools retains FDSelect & font dicts for missing glyphs. do the same */
	glyph = i;
      }
      fd = src.get_fd (glyph);
      set.add (fd);

      if (fd != prev_fd)
      {
	num_ranges++;
	prev_fd = fd;
	code_pair_t pair = { fd, i };
	fdselect_ranges.push (pair);
      }
    }

    subset_fd_count = set.get_population ();
    if (subset_fd_count == fdCount)
    {
      /* all font dicts belong to the subset. no need to subset FDSelect & FDArray */
      fdmap.identity (fdCount);
    }
    else
    {
      /* create a fdmap */
      fdmap.reset ();

      hb_codepoint_t fd = CFF_UNDEF_CODE;
      while (set.next (&fd))
	fdmap.add (fd);
      if (unlikely (fdmap.get_population () != subset_fd_count))
	return false;
    }

    /* update each font dict index stored as "code" in fdselect_ranges */
    for (unsigned int i = 0; i < fdselect_ranges.length; i++)
      fdselect_ranges[i].code = fdmap[fdselect_ranges[i].code];
  }

  /* determine which FDSelect format is most compact */
  if (subset_fd_count > 0xFF)
  {
    if (unlikely (src.format != 4))
      return false;
    subset_fdselect_format = 4;
    subset_fdselect_size = FDSelect::min_size + FDSelect4::min_size + FDSelect4_Range::static_size * num_ranges + HBUINT32::static_size;
  }
  else
  {
#if CFF_SERIALIZE_FDSELECT_0
    unsigned int format0_size = FDSelect::min_size + FDSelect0::min_size + HBUINT8::static_size * subset_num_glyphs;
#endif
    unsigned int format3_size = FDSelect::min_size + FDSelect3::min_size + FDSelect3_Range::static_size * num_ranges + HBUINT16::static_size;

#if CFF_SERIALIZE_FDSELECT_0
    if (format0_size <= format3_size)
    {
      // subset_fdselect_format = 0;
      subset_fdselect_size = format0_size;
    }
    else
#endif
    {
      subset_fdselect_format = 3;
      subset_fdselect_size = format3_size;
    }
  }

  return true;
}

template <typename FDSELECT3_4>
static inline bool
serialize_fdselect_3_4 (hb_serialize_context_t *c,
			const unsigned int num_glyphs,
			const FDSelect &src,
			unsigned int size,
			const hb_vector_t<code_pair_t> &fdselect_ranges)
{
  TRACE_SERIALIZE (this);
  FDSELECT3_4 *p = c->allocate_size<FDSELECT3_4> (size);
  if (unlikely (!p)) return_trace (false);
  p->nRanges () = fdselect_ranges.length;
  for (unsigned int i = 0; i < fdselect_ranges.length; i++)
  {
    p->ranges[i].first = fdselect_ranges[i].glyph;
    p->ranges[i].fd = fdselect_ranges[i].code;
  }
  p->sentinel () = num_glyphs;
  return_trace (true);
}

/* Serialize a subset FDSelect format planned above. */
bool
hb_serialize_cff_fdselect (hb_serialize_context_t *c,
			   const unsigned int num_glyphs,
			   const FDSelect &src,
			   unsigned int fd_count,
			   unsigned int fdselect_format,
			   unsigned int size,
			   const hb_vector_t<code_pair_t> &fdselect_ranges)
{
  TRACE_SERIALIZE (this);
  FDSelect *p = c->allocate_min<FDSelect> ();
  if (unlikely (!p)) return_trace (false);
  p->format = fdselect_format;
  size -= FDSelect::min_size;

  switch (fdselect_format)
  {
#if CFF_SERIALIZE_FDSELECT_0
  case 0:
  {
    FDSelect0 *p = c->allocate_size<FDSelect0> (size);
    if (unlikely (!p)) return_trace (false);
    unsigned int range_index = 0;
    unsigned int fd = fdselect_ranges[range_index++].code;
    for (unsigned int i = 0; i < num_glyphs; i++)
    {
      if ((range_index < fdselect_ranges.len) &&
	  (i >= fdselect_ranges[range_index].glyph))
      {
	fd = fdselect_ranges[range_index++].code;
      }
      p->fds[i] = fd;
    }
    return_trace (true);
  }
#endif /* CFF_SERIALIZE_FDSELECT_0 */

  case 3:
    return serialize_fdselect_3_4<FDSelect3> (c, num_glyphs, src,
					      size, fdselect_ranges);

  case 4:
    return serialize_fdselect_3_4<FDSelect4> (c, num_glyphs, src,
					      size, fdselect_ranges);

  default:
    return_trace (false);
  }
}


#endif