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 = hb_set_create ();
70 if (unlikely (set == &Null (hb_set_t))) return false;
71 hb_codepoint_t prev_fd = CFF_UNDEF_CODE;
72 for (hb_codepoint_t i = 0; i < subset_num_glyphs; i++)
73 {
74 hb_codepoint_t glyph;
75 hb_codepoint_t fd;
76 if (!plan->old_gid_for_new_gid (i, &glyph))
77 {
78 /* fonttools retains FDSelect & font dicts for missing glyphs. do the same */
79 glyph = i;
80 }
81 fd = src.get_fd (glyph);
82 set->add (fd);
83
84 if (fd != prev_fd)
85 {
86 num_ranges++;
87 prev_fd = fd;
88 code_pair_t pair = { fd, i };
89 fdselect_ranges.push (pair);
90 }
91 }
92
93 subset_fd_count = set->get_population ();
94 if (subset_fd_count == fdCount)
95 {
96 /* all font dicts belong to the subset. no need to subset FDSelect & FDArray */
97 fdmap.identity (fdCount);
98 hb_set_destroy (set);
99 }
100 else
101 {
102 /* create a fdmap */
103 fdmap.reset ();
104
105 hb_codepoint_t fd = CFF_UNDEF_CODE;
106 while (set->next (&fd))
107 fdmap.add (fd);
108 hb_set_destroy (set);
109 if (unlikely (fdmap.get_population () != subset_fd_count))
110 return false;
111 }
112
113 /* update each font dict index stored as "code" in fdselect_ranges */
114 for (unsigned int i = 0; i < fdselect_ranges.length; i++)
115 fdselect_ranges[i].code = fdmap[fdselect_ranges[i].code];
116 }
117
118 /* determine which FDSelect format is most compact */
119 if (subset_fd_count > 0xFF)
120 {
121 if (unlikely (src.format != 4))
122 return false;
123 subset_fdselect_format = 4;
124 subset_fdselect_size = FDSelect::min_size + FDSelect4::min_size + FDSelect4_Range::static_size * num_ranges + HBUINT32::static_size;
125 }
126 else
127 {
128 #if CFF_SERIALIZE_FDSELECT_0
129 unsigned int format0_size = FDSelect::min_size + FDSelect0::min_size + HBUINT8::static_size * subset_num_glyphs;
130 #endif
131 unsigned int format3_size = FDSelect::min_size + FDSelect3::min_size + FDSelect3_Range::static_size * num_ranges + HBUINT16::static_size;
132
133 #if CFF_SERIALIZE_FDSELECT_0
134 if (format0_size <= format3_size)
135 {
136 // subset_fdselect_format = 0;
137 subset_fdselect_size = format0_size;
138 }
139 else
140 #endif
141 {
142 subset_fdselect_format = 3;
143 subset_fdselect_size = format3_size;
144 }
145 }
146
147 return true;
148 }
149
150 template <typename FDSELECT3_4>
151 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)152 serialize_fdselect_3_4 (hb_serialize_context_t *c,
153 const unsigned int num_glyphs,
154 const FDSelect &src,
155 unsigned int size,
156 const hb_vector_t<code_pair_t> &fdselect_ranges)
157 {
158 TRACE_SERIALIZE (this);
159 FDSELECT3_4 *p = c->allocate_size<FDSELECT3_4> (size);
160 if (unlikely (!p)) return_trace (false);
161 p->nRanges () = fdselect_ranges.length;
162 for (unsigned int i = 0; i < fdselect_ranges.length; i++)
163 {
164 p->ranges[i].first = fdselect_ranges[i].glyph;
165 p->ranges[i].fd = fdselect_ranges[i].code;
166 }
167 p->sentinel () = num_glyphs;
168 return_trace (true);
169 }
170
171 /* Serialize a subset FDSelect format planned above. */
172 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)173 hb_serialize_cff_fdselect (hb_serialize_context_t *c,
174 const unsigned int num_glyphs,
175 const FDSelect &src,
176 unsigned int fd_count,
177 unsigned int fdselect_format,
178 unsigned int size,
179 const hb_vector_t<code_pair_t> &fdselect_ranges)
180 {
181 TRACE_SERIALIZE (this);
182 FDSelect *p = c->allocate_min<FDSelect> ();
183 if (unlikely (!p)) return_trace (false);
184 p->format = fdselect_format;
185 size -= FDSelect::min_size;
186
187 switch (fdselect_format)
188 {
189 #if CFF_SERIALIZE_FDSELECT_0
190 case 0:
191 {
192 FDSelect0 *p = c->allocate_size<FDSelect0> (size);
193 if (unlikely (!p)) return_trace (false);
194 unsigned int range_index = 0;
195 unsigned int fd = fdselect_ranges[range_index++].code;
196 for (unsigned int i = 0; i < num_glyphs; i++)
197 {
198 if ((range_index < fdselect_ranges.len) &&
199 (i >= fdselect_ranges[range_index].glyph))
200 {
201 fd = fdselect_ranges[range_index++].code;
202 }
203 p->fds[i] = fd;
204 }
205 return_trace (true);
206 }
207 #endif /* CFF_SERIALIZE_FDSELECT_0 */
208
209 case 3:
210 return serialize_fdselect_3_4<FDSelect3> (c, num_glyphs, src,
211 size, fdselect_ranges);
212
213 case 4:
214 return serialize_fdselect_3_4<FDSelect4> (c, num_glyphs, src,
215 size, fdselect_ranges);
216
217 default:
218 return_trace (false);
219 }
220 }
221
222
223 #endif
224