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-ot-cff-common.hh"
28 #include "hb-ot-cff2-table.hh"
29 #include "hb-subset-cff-common.hh"
30
31 /* Disable FDSelect format 0 for compatibility with fonttools which doesn't seem choose it.
32 * Rarely any/much smaller than format 3 anyway. */
33 #define CFF_SERIALIZE_FDSELECT_0 0
34
35 using namespace CFF;
36
37 /**
38 * hb_plan_subset_cff_fdselect
39 * Determine an optimal FDSelect format according to a provided plan.
40 *
41 * Return value: FDSelect format, size, and ranges for the most compact subset FDSelect
42 * along with a font index remapping table
43 **/
44
45 bool
46 hb_plan_subset_cff_fdselect (const hb_vector_t<hb_codepoint_t> &glyphs,
47 unsigned int fdCount,
48 const FDSelect &src, /* IN */
49 unsigned int &subset_fd_count /* OUT */,
50 unsigned int &subset_fdselect_size /* OUT */,
51 unsigned int &subset_fdselect_format /* OUT */,
52 hb_vector_t<code_pair_t> &fdselect_ranges /* OUT */,
53 remap_t &fdmap /* OUT */)
54 {
55 subset_fd_count = 0;
56 subset_fdselect_size = 0;
57 subset_fdselect_format = 0;
58 unsigned int num_ranges = 0;
59
60 unsigned int subset_num_glyphs = glyphs.length;
61 if (subset_num_glyphs == 0)
62 return true;
63
64 {
65 /* use hb_set to determine the subset of font dicts */
66 hb_set_t *set = hb_set_create ();
67 if (set == &Null (hb_set_t))
68 return false;
69 hb_codepoint_t prev_fd = CFF_UNDEF_CODE;
70 for (hb_codepoint_t i = 0; i < subset_num_glyphs; i++)
71 {
72 hb_codepoint_t fd = src.get_fd (glyphs[i]);
73 set->add (fd);
74
75 if (fd != prev_fd)
76 {
77 num_ranges++;
78 prev_fd = fd;
79 code_pair_t pair = { fd, i };
80 fdselect_ranges.push (pair);
81 }
82 }
83
84 subset_fd_count = set->get_population ();
85 if (subset_fd_count == fdCount)
86 {
87 /* all font dicts belong to the subset. no need to subset FDSelect & FDArray */
88 fdmap.identity (fdCount);
89 hb_set_destroy (set);
90 }
91 else
92 {
93 /* create a fdmap */
94 if (!fdmap.reset (fdCount))
95 {
96 hb_set_destroy (set);
97 return false;
98 }
99
100 hb_codepoint_t fd = CFF_UNDEF_CODE;
101 while (set->next (&fd))
102 fdmap.add (fd);
103 hb_set_destroy (set);
104 if (unlikely (fdmap.get_count () != subset_fd_count))
105 return false;
106 }
107
108 /* update each font dict index stored as "code" in fdselect_ranges */
109 for (unsigned int i = 0; i < fdselect_ranges.length; i++)
110 fdselect_ranges[i].code = fdmap[fdselect_ranges[i].code];
111 }
112
113 /* determine which FDSelect format is most compact */
114 if (subset_fd_count > 0xFF)
115 {
116 if (unlikely (src.format != 4))
117 return false;
118 subset_fdselect_format = 4;
119 subset_fdselect_size = FDSelect::min_size + FDSelect4::min_size + FDSelect4_Range::static_size * num_ranges + HBUINT32::static_size;
120 }
121 else
122 {
123 #if CFF_SERIALIZE_FDSELECT_0
124 unsigned int format0_size = FDSelect::min_size + FDSelect0::min_size + HBUINT8::static_size * subset_num_glyphs;
125 #endif
126 unsigned int format3_size = FDSelect::min_size + FDSelect3::min_size + FDSelect3_Range::static_size * num_ranges + HBUINT16::static_size;
127
128 #if CFF_SERIALIZE_FDSELECT_0
129 if (format0_size <= format3_size)
130 {
131 // subset_fdselect_format = 0;
132 subset_fdselect_size = format0_size;
133 }
134 else
135 #endif
136 {
137 subset_fdselect_format = 3;
138 subset_fdselect_size = format3_size;
139 }
140 }
141
142 return true;
143 }
144
145 template <typename FDSELECT3_4>
146 static inline bool
147 serialize_fdselect_3_4 (hb_serialize_context_t *c,
148 const unsigned int num_glyphs,
149 const FDSelect &src,
150 unsigned int size,
151 const hb_vector_t<code_pair_t> &fdselect_ranges)
152 {
153 TRACE_SERIALIZE (this);
154 FDSELECT3_4 *p = c->allocate_size<FDSELECT3_4> (size);
155 if (unlikely (p == nullptr)) return_trace (false);
156 p->nRanges ().set (fdselect_ranges.length);
157 for (unsigned int i = 0; i < fdselect_ranges.length; i++)
158 {
159 p->ranges[i].first.set (fdselect_ranges[i].glyph);
160 p->ranges[i].fd.set (fdselect_ranges[i].code);
161 }
162 p->sentinel().set (num_glyphs);
163 return_trace (true);
164 }
165
166 /**
167 * hb_serialize_cff_fdselect
168 * Serialize a subset FDSelect format planned above.
169 **/
170 bool
171 hb_serialize_cff_fdselect (hb_serialize_context_t *c,
172 const unsigned int num_glyphs,
173 const FDSelect &src,
174 unsigned int fd_count,
175 unsigned int fdselect_format,
176 unsigned int size,
177 const hb_vector_t<code_pair_t> &fdselect_ranges)
178 {
179 TRACE_SERIALIZE (this);
180 FDSelect *p = c->allocate_min<FDSelect> ();
181 if (unlikely (p == nullptr)) return_trace (false);
182 p->format.set (fdselect_format);
183 size -= FDSelect::min_size;
184
185 switch (fdselect_format)
186 {
187 #if CFF_SERIALIZE_FDSELECT_0
188 case 0:
189 {
190 FDSelect0 *p = c->allocate_size<FDSelect0> (size);
191 if (unlikely (p == nullptr)) return_trace (false);
192 unsigned int range_index = 0;
193 unsigned int fd = fdselect_ranges[range_index++].code;
194 for (unsigned int i = 0; i < num_glyphs; i++)
195 {
196 if ((range_index < fdselect_ranges.len) &&
197 (i >= fdselect_ranges[range_index].glyph))
198 {
199 fd = fdselect_ranges[range_index++].code;
200 }
201 p->fds[i].set (fd);
202 }
203 break;
204 }
205 #endif /* CFF_SERIALIZE_FDSELECT_0 */
206
207 case 3:
208 return serialize_fdselect_3_4<FDSelect3> (c,
209 num_glyphs,
210 src,
211 size,
212 fdselect_ranges);
213
214 case 4:
215 return serialize_fdselect_3_4<FDSelect4> (c,
216 num_glyphs,
217 src,
218 size,
219 fdselect_ranges);
220
221 default:
222 assert(false);
223 }
224
225 return_trace (true);
226 }