hb-subset-cff-common.cc (6730B)
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 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 hb_pair_t<unsigned, hb_codepoint_t> last_range {0, 0}; 72 auto it = hb_iter (plan->new_to_old_gid_list); 73 auto _ = *it; 74 for (hb_codepoint_t gid = 0; gid < subset_num_glyphs; gid++) 75 { 76 hb_codepoint_t old_glyph; 77 if (gid == _.first) 78 { 79 old_glyph = _.second; 80 _ = *++it; 81 } 82 else 83 { 84 /* fonttools retains FDSelect & font dicts for missing glyphs. do the same */ 85 old_glyph = gid; 86 } 87 if (old_glyph >= last_range.second) 88 last_range = src.get_fd_range (old_glyph); 89 unsigned fd = last_range.first; 90 91 if (fd != prev_fd) 92 { 93 set.add (fd); 94 num_ranges++; 95 prev_fd = fd; 96 fdselect_ranges.push (code_pair_t { fd, gid }); 97 98 if (gid == old_glyph) 99 gid = hb_min (_.first - 1, last_range.second - 1); 100 } 101 } 102 103 subset_fd_count = set.get_population (); 104 if (subset_fd_count == fdCount) 105 { 106 /* all font dicts belong to the subset. no need to subset FDSelect & FDArray */ 107 fdmap.identity (fdCount); 108 } 109 else 110 { 111 /* create a fdmap */ 112 fdmap.reset (); 113 114 hb_codepoint_t fd = CFF_UNDEF_CODE; 115 while (set.next (&fd)) 116 fdmap.add (fd); 117 if (unlikely (fdmap.get_population () != subset_fd_count)) 118 return false; 119 } 120 121 /* update each font dict index stored as "code" in fdselect_ranges */ 122 for (unsigned int i = 0; i < fdselect_ranges.length; i++) 123 fdselect_ranges[i].code = fdmap[fdselect_ranges[i].code]; 124 } 125 126 /* determine which FDSelect format is most compact */ 127 if (subset_fd_count > 0xFF) 128 { 129 if (unlikely (src.format != 4)) 130 return false; 131 subset_fdselect_format = 4; 132 subset_fdselect_size = FDSelect::min_size + FDSelect4::min_size + FDSelect4_Range::static_size * num_ranges + HBUINT32::static_size; 133 } 134 else 135 { 136 #if CFF_SERIALIZE_FDSELECT_0 137 unsigned int format0_size = FDSelect::min_size + FDSelect0::min_size + HBUINT8::static_size * subset_num_glyphs; 138 #endif 139 unsigned int format3_size = FDSelect::min_size + FDSelect3::min_size + FDSelect3_Range::static_size * num_ranges + HBUINT16::static_size; 140 141 #if CFF_SERIALIZE_FDSELECT_0 142 if (format0_size <= format3_size) 143 { 144 // subset_fdselect_format = 0; 145 subset_fdselect_size = format0_size; 146 } 147 else 148 #endif 149 { 150 subset_fdselect_format = 3; 151 subset_fdselect_size = format3_size; 152 } 153 } 154 155 return true; 156 } 157 158 template <typename FDSELECT3_4> 159 static inline bool 160 serialize_fdselect_3_4 (hb_serialize_context_t *c, 161 const unsigned int num_glyphs, 162 const FDSelect &src, 163 unsigned int size, 164 const hb_vector_t<code_pair_t> &fdselect_ranges) 165 { 166 TRACE_SERIALIZE (this); 167 FDSELECT3_4 *p = c->allocate_size<FDSELECT3_4> (size); 168 if (unlikely (!p)) return_trace (false); 169 p->nRanges () = fdselect_ranges.length; 170 for (unsigned int i = 0; i < fdselect_ranges.length; i++) 171 { 172 p->ranges[i].first = fdselect_ranges[i].glyph; 173 p->ranges[i].fd = fdselect_ranges[i].code; 174 } 175 p->sentinel () = num_glyphs; 176 return_trace (true); 177 } 178 179 /* Serialize a subset FDSelect format planned above. */ 180 bool 181 hb_serialize_cff_fdselect (hb_serialize_context_t *c, 182 const unsigned int num_glyphs, 183 const FDSelect &src, 184 unsigned int fd_count, 185 unsigned int fdselect_format, 186 unsigned int size, 187 const hb_vector_t<code_pair_t> &fdselect_ranges) 188 { 189 TRACE_SERIALIZE (this); 190 FDSelect *p = c->allocate_min<FDSelect> (); 191 if (unlikely (!p)) return_trace (false); 192 p->format = fdselect_format; 193 size -= FDSelect::min_size; 194 195 switch (fdselect_format) 196 { 197 #if CFF_SERIALIZE_FDSELECT_0 198 case 0: 199 { 200 FDSelect0 *p = c->allocate_size<FDSelect0> (size); 201 if (unlikely (!p)) return_trace (false); 202 unsigned int range_index = 0; 203 unsigned int fd = fdselect_ranges[range_index++].code; 204 for (unsigned int i = 0; i < num_glyphs; i++) 205 { 206 if ((range_index < fdselect_ranges.len) && 207 (i >= fdselect_ranges[range_index].glyph)) 208 { 209 fd = fdselect_ranges[range_index++].code; 210 } 211 p->fds[i] = fd; 212 } 213 return_trace (true); 214 } 215 #endif /* CFF_SERIALIZE_FDSELECT_0 */ 216 217 case 3: 218 return serialize_fdselect_3_4<FDSelect3> (c, num_glyphs, src, 219 size, fdselect_ranges); 220 221 case 4: 222 return serialize_fdselect_3_4<FDSelect4> (c, num_glyphs, src, 223 size, fdselect_ranges); 224 225 default: 226 return_trace (false); 227 } 228 } 229 230 231 #endif