1 /*
2 * Copyright © 2018 Adobe 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 * Adobe Author(s): Michiharu Ariza
25 */
26
27 #include "hb.hh"
28
29 #ifndef HB_NO_SUBSET_CFF
30
31 #include "hb-ot-cff-common.hh"
32 #include "hb-ot-cff2-table.hh"
33 #include "hb-subset-cff-common.hh"
34
35 /* Disable FDSelect format 0 for compatibility with fonttools which doesn't seem choose it.
36 * Rarely any/much smaller than format 3 anyway. */
37 #define CFF_SERIALIZE_FDSELECT_0 0
38
39 using namespace CFF;
40
41
42 /* Determine an optimal FDSelect format according to a provided plan.
43 *
44 * Return value: FDSelect format, size, and ranges for the most compact subset FDSelect
45 * along with a font index remapping table
46 */
47
48 bool
hb_plan_subset_cff_fdselect(const hb_subset_plan_t * plan,unsigned int fdCount,const FDSelect & src,unsigned int & subset_fd_count,unsigned int & subset_fdselect_size,unsigned int & subset_fdselect_format,hb_vector_t<code_pair_t> & fdselect_ranges,hb_inc_bimap_t & fdmap)49 hb_plan_subset_cff_fdselect (const hb_subset_plan_t *plan,
50 unsigned int fdCount,
51 const FDSelect &src, /* IN */
52 unsigned int &subset_fd_count /* OUT */,
53 unsigned int &subset_fdselect_size /* OUT */,
54 unsigned int &subset_fdselect_format /* OUT */,
55 hb_vector_t<code_pair_t> &fdselect_ranges /* OUT */,
56 hb_inc_bimap_t &fdmap /* OUT */)
57 {
58 subset_fd_count = 0;
59 subset_fdselect_size = 0;
60 subset_fdselect_format = 0;
61 unsigned int num_ranges = 0;
62
63 unsigned int subset_num_glyphs = plan->num_output_glyphs ();
64 if (subset_num_glyphs == 0)
65 return true;
66
67 {
68 /* use hb_set to determine the subset of font dicts */
69 hb_set_t set;
70 hb_codepoint_t prev_fd = CFF_UNDEF_CODE;
71 for (hb_codepoint_t i = 0; i < subset_num_glyphs; i++)
72 {
73 hb_codepoint_t glyph;
74 hb_codepoint_t fd;
75 if (!plan->old_gid_for_new_gid (i, &glyph))
76 {
77 /* fonttools retains FDSelect & font dicts for missing glyphs. do the same */
78 glyph = i;
79 }
80 fd = src.get_fd (glyph);
81 set.add (fd);
82
83 if (fd != prev_fd)
84 {
85 num_ranges++;
86 prev_fd = fd;
87 code_pair_t pair = { fd, i };
88 fdselect_ranges.push (pair);
89 }
90 }
91
92 subset_fd_count = set.get_population ();
93 if (subset_fd_count == fdCount)
94 {
95 /* all font dicts belong to the subset. no need to subset FDSelect & FDArray */
96 fdmap.identity (fdCount);
97 }
98 else
99 {
100 /* create a fdmap */
101 fdmap.reset ();
102
103 hb_codepoint_t fd = CFF_UNDEF_CODE;
104 while (set.next (&fd))
105 fdmap.add (fd);
106 if (unlikely (fdmap.get_population () != subset_fd_count))
107 return false;
108 }
109
110 /* update each font dict index stored as "code" in fdselect_ranges */
111 for (unsigned int i = 0; i < fdselect_ranges.length; i++)
112 fdselect_ranges[i].code = fdmap[fdselect_ranges[i].code];
113 }
114
115 /* determine which FDSelect format is most compact */
116 if (subset_fd_count > 0xFF)
117 {
118 if (unlikely (src.format != 4))
119 return false;
120 subset_fdselect_format = 4;
121 subset_fdselect_size = FDSelect::min_size + FDSelect4::min_size + FDSelect4_Range::static_size * num_ranges + HBUINT32::static_size;
122 }
123 else
124 {
125 #if CFF_SERIALIZE_FDSELECT_0
126 unsigned int format0_size = FDSelect::min_size + FDSelect0::min_size + HBUINT8::static_size * subset_num_glyphs;
127 #endif
128 unsigned int format3_size = FDSelect::min_size + FDSelect3::min_size + FDSelect3_Range::static_size * num_ranges + HBUINT16::static_size;
129
130 #if CFF_SERIALIZE_FDSELECT_0
131 if (format0_size <= format3_size)
132 {
133 // subset_fdselect_format = 0;
134 subset_fdselect_size = format0_size;
135 }
136 else
137 #endif
138 {
139 subset_fdselect_format = 3;
140 subset_fdselect_size = format3_size;
141 }
142 }
143
144 return true;
145 }
146
147 template <typename FDSELECT3_4>
148 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)149 serialize_fdselect_3_4 (hb_serialize_context_t *c,
150 const unsigned int num_glyphs,
151 const FDSelect &src,
152 unsigned int size,
153 const hb_vector_t<code_pair_t> &fdselect_ranges)
154 {
155 TRACE_SERIALIZE (this);
156 FDSELECT3_4 *p = c->allocate_size<FDSELECT3_4> (size);
157 if (unlikely (!p)) return_trace (false);
158 p->nRanges () = fdselect_ranges.length;
159 for (unsigned int i = 0; i < fdselect_ranges.length; i++)
160 {
161 p->ranges[i].first = fdselect_ranges[i].glyph;
162 p->ranges[i].fd = fdselect_ranges[i].code;
163 }
164 p->sentinel () = num_glyphs;
165 return_trace (true);
166 }
167
168 /* Serialize a subset FDSelect format planned above. */
169 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)170 hb_serialize_cff_fdselect (hb_serialize_context_t *c,
171 const unsigned int num_glyphs,
172 const FDSelect &src,
173 unsigned int fd_count,
174 unsigned int fdselect_format,
175 unsigned int size,
176 const hb_vector_t<code_pair_t> &fdselect_ranges)
177 {
178 TRACE_SERIALIZE (this);
179 FDSelect *p = c->allocate_min<FDSelect> ();
180 if (unlikely (!p)) return_trace (false);
181 p->format = fdselect_format;
182 size -= FDSelect::min_size;
183
184 switch (fdselect_format)
185 {
186 #if CFF_SERIALIZE_FDSELECT_0
187 case 0:
188 {
189 FDSelect0 *p = c->allocate_size<FDSelect0> (size);
190 if (unlikely (!p)) return_trace (false);
191 unsigned int range_index = 0;
192 unsigned int fd = fdselect_ranges[range_index++].code;
193 for (unsigned int i = 0; i < num_glyphs; i++)
194 {
195 if ((range_index < fdselect_ranges.len) &&
196 (i >= fdselect_ranges[range_index].glyph))
197 {
198 fd = fdselect_ranges[range_index++].code;
199 }
200 p->fds[i] = fd;
201 }
202 return_trace (true);
203 }
204 #endif /* CFF_SERIALIZE_FDSELECT_0 */
205
206 case 3:
207 return serialize_fdselect_3_4<FDSelect3> (c, num_glyphs, src,
208 size, fdselect_ranges);
209
210 case 4:
211 return serialize_fdselect_3_4<FDSelect4> (c, num_glyphs, src,
212 size, fdselect_ranges);
213
214 default:
215 return_trace (false);
216 }
217 }
218
219
220 #endif
221