1 // afblue.dat 2 // 3 // Auto-fitter data for blue strings. 4 // 5 // Copyright 2013-2015 by 6 // David Turner, Robert Wilhelm, and Werner Lemberg. 7 // 8 // This file is part of the FreeType project, and may only be used, 9 // modified, and distributed under the terms of the FreeType project 10 // license, LICENSE.TXT. By continuing to use, modify, or distribute 11 // this file you indicate that you have read the license and 12 // understand and accept it fully. 13 14 15 // This file contains data specific to blue zones. It gets processed by 16 // a script to simulate `jagged arrays', with enumeration values holding 17 // offsets into the arrays. 18 // 19 // The format of the file is rather simple: A section starts with three 20 // labels separated by whitespace and followed by a colon (everything in a 21 // single line); the first label gives the name of the enumeration template, 22 // the second the name of the array template, and the third the name of the 23 // `maximum' template, holding the size of the largest array element. The 24 // script then fills the corresponding templates (indicated by `@' 25 // characters around the name). 26 // 27 // A section contains one or more data records. Each data record consists 28 // of two or more lines. The first line holds the enumeration name, and the 29 // remaining lines the corresponding array data. 30 // 31 // There are two possible representations for array data. 32 // 33 // - A string of characters in UTF-8 encoding enclosed in double quotes, 34 // using C syntax. There can be only one string per line, thus the 35 // starting and ending double quote must be the first and last character 36 // in the line, respectively, ignoring whitespace before and after the 37 // string. Space characters within the string are ignored too. If there 38 // are multiple strings (in multiple lines), they are concatenated to a 39 // single string. In the output, a string gets represented as a series of 40 // singles bytes, followed by a zero byte. The enumeration values simply 41 // hold byte offsets to the start of the corresponding strings. 42 // 43 // - Data blocks enclosed in balanced braces, which get copied verbatim and 44 // which can span multiple lines. The opening brace of a block must be 45 // the first character of a line (ignoring whitespace), and the closing 46 // brace the last (ignoring whitespace also). The script appends a comma 47 // character after each block and counts the number of blocks to set the 48 // enumeration values. 49 // 50 // A section can contain either strings only or data blocks only. 51 // 52 // A comment line starts with `//'; it gets removed. A preprocessor 53 // directive line (using the standard syntax of `cpp') starts with `#' and 54 // gets copied verbatim to both the enumeration and the array. Whitespace 55 // outside of a string is insignificant. 56 // 57 // Preprocessor directives are ignored while the script computes maximum 58 // values; this essentially means that the maximum values can easily be too 59 // large. Given that the purpose of those values is to create local 60 // fixed-size arrays at compile time for further processing of the blue zone 61 // data, this isn't a problem. Note the the final zero byte of a string is 62 // not counted. Note also that the count holds the number of UTF-8 encoded 63 // characters, not bytes. 64 65 66 // The blue zone string data, to be used in the blue stringsets below. 67 68 AF_BLUE_STRING_ENUM AF_BLUE_STRINGS_ARRAY AF_BLUE_STRING_MAX_LEN: 69 70 AF_BLUE_STRING_ARABIC_TOP 71 " " 72 AF_BLUE_STRING_ARABIC_JOIN 73 " " 74 75 AF_BLUE_STRING_CYRILLIC_CAPITAL_TOP 76 "" 77 AF_BLUE_STRING_CYRILLIC_CAPITAL_BOTTOM 78 "" 79 AF_BLUE_STRING_CYRILLIC_SMALL 80 "" 81 AF_BLUE_STRING_CYRILLIC_SMALL_DESCENDER 82 "" 83 84 // we separate the letters with spaces to avoid ligatures; 85 // this is just for convenience to simplify reading 86 AF_BLUE_STRING_DEVANAGARI_BASE 87 " " 88 AF_BLUE_STRING_DEVANAGARI_TOP 89 " " 90 // note that some fonts have extreme variation in the height of the 91 // round head elements; for this reason we also define the `base' 92 // blue zone, which must be always present 93 AF_BLUE_STRING_DEVANAGARI_HEAD 94 " " 95 AF_BLUE_STRING_DEVANAGARI_BOTTOM 96 " " 97 98 AF_BLUE_STRING_GREEK_CAPITAL_TOP 99 "" 100 AF_BLUE_STRING_GREEK_CAPITAL_BOTTOM 101 "" 102 AF_BLUE_STRING_GREEK_SMALL_BETA_TOP 103 "" 104 AF_BLUE_STRING_GREEK_SMALL 105 "" 106 AF_BLUE_STRING_GREEK_SMALL_DESCENDER 107 "" 108 109 AF_BLUE_STRING_HEBREW_TOP 110 "" 111 AF_BLUE_STRING_HEBREW_BOTTOM 112 "" 113 AF_BLUE_STRING_HEBREW_DESCENDER 114 "" 115 116 AF_BLUE_STRING_LATIN_CAPITAL_TOP 117 "THEZOCQS" 118 AF_BLUE_STRING_LATIN_CAPITAL_BOTTOM 119 "HEZLOCUS" 120 AF_BLUE_STRING_LATIN_SMALL_F_TOP 121 "fijkdbh" 122 AF_BLUE_STRING_LATIN_SMALL 123 "xzroesc" 124 AF_BLUE_STRING_LATIN_SMALL_DESCENDER 125 "pqgjy" 126 127 // we separate the letters with spaces to avoid ligatures; 128 // this is just for convenience to simplify reading 129 AF_BLUE_STRING_TELUGU_TOP 130 " " 131 AF_BLUE_STRING_TELUGU_BOTTOM 132 " " 133 134 AF_BLUE_STRING_THAI_TOP 135 " " 136 AF_BLUE_STRING_THAI_BOTTOM 137 " " 138 AF_BLUE_STRING_THAI_ASCENDER 139 " " 140 AF_BLUE_STRING_THAI_LARGE_ASCENDER 141 " " 142 AF_BLUE_STRING_THAI_DESCENDER 143 " " 144 AF_BLUE_STRING_THAI_LARGE_DESCENDER 145 " " 146 AF_BLUE_STRING_THAI_DIGIT_TOP 147 " " 148 149 150 #ifdef AF_CONFIG_OPTION_CJK 151 152 AF_BLUE_STRING_CJK_TOP 153 "" 154 "" 155 "" 156 " |" 157 "" 158 "" 159 "" 160 "" 161 AF_BLUE_STRING_CJK_BOTTOM 162 "" 163 "" 164 "" 165 " |" 166 "" 167 "" 168 "" 169 "" 170 171 #ifdef AF_CONFIG_OPTION_CJK_BLUE_HANI_VERT 172 173 AF_BLUE_STRING_CJK_LEFT 174 "" 175 "" 176 "" 177 " |" 178 "" 179 "" 180 "" 181 "" 182 AF_BLUE_STRING_CJK_RIGHT 183 "" 184 "" 185 "" 186 " |" 187 "" 188 "" 189 "" 190 "" 191 192 #endif /* AF_CONFIG_OPTION_CJK_BLUE_HANI_VERT */ 193 194 #endif /* AF_CONFIG_OPTION_CJK */ 195 196 197 // The blue zone stringsets, as used in the script styles, cf. `afstyles.h'. 198 // 199 // The AF_BLUE_PROPERTY_XXX flags are defined in `afblue.h'; here some 200 // explanations. 201 // 202 // A blue zone in general is defined by a reference and an overshoot line. 203 // During the hinting process, all coordinate values between those two lines 204 // are set equal to the reference value, provided that the blue zone is not 205 // wider than 0.75 pixels (otherwise the blue zone gets ignored). All 206 // entries must have `AF_BLUE_STRING_MAX' as the final line. 207 // 208 // During the glyph analysis, edges are sorted from bottom to top, and then 209 // sequentially checked, edge by edge, against the blue zones in the order 210 // given below. 211 // 212 // 213 // latin auto-hinter 214 // ----------------- 215 // 216 // Characters in a blue string are automatically classified as having a flat 217 // (reference) or a round (overshoot) extremum. The blue zone is then set 218 // up by the mean values of all flat extrema and all round extrema, 219 // respectively. Only horizontal blue zones (i.e., adjusting vertical 220 // coordinate values) are supported. 221 // 222 // For the latin auto-hinter, the overshoot should be larger than the 223 // reference for top zones, and vice versa for bottom zones. 224 // 225 // LATIN_TOP 226 // Take the maximum flat and round coordinate values of the blue string 227 // characters for computing the blue zone's reference and overshoot 228 // values. 229 // 230 // If not set, take the minimum values. 231 // 232 // LATIN_NEUTRAL 233 // Ignore round extrema and define the blue zone with flat values only. 234 // Both top and bottom of contours can match. This is useful for 235 // scripts like Devanagari where vowel signs attach to the base 236 // character and are implemented as components of composite glyphs. 237 // 238 // If not set, both round and flat extrema are taken into account. 239 // Additionally, only the top or the bottom of a contour can match, 240 // depending on the LATIN_TOP flag. 241 // 242 // Neutral blue zones should always follow non-neutral blue zones. 243 // 244 // LATIN_X_HEIGHT 245 // Scale all glyphs vertically from the corresponding script to make the 246 // reference line of this blue zone align on the grid. The scaling 247 // takes place before all other blue zones get aligned to the grid. 248 // Only one blue character string of a script style can have this flag. 249 // 250 // LATIN_LONG 251 // Apply an additional constraint for blue zone values: Don't 252 // necessarily use the extremum as-is but a segment of the topmost (or 253 // bottommost) contour that is longer than a heuristic threshold, and 254 // which is not too far away vertically from the real extremum. This 255 // ensures that small bumps in the outline are ignored (for example, the 256 // `vertical serifs' found in many Hebrew glyph designs). 257 // 258 // The segment must be at least EM/25 font units long, and the distance 259 // to the extremum must be smaller than EM/4. 260 // 261 // 262 // cjk auto-hinter 263 // --------------- 264 // 265 // Characters in a blue string are *not* automatically classified. Instead, 266 // first come the characters used for the overshoot value, then the 267 // character `|', then the characters used for the reference value. The 268 // blue zone is then set up by the mean values of all reference values and 269 // all overshoot values, respectively. Both horizontal and vertical blue 270 // zones (i.e., adjusting vertical and horizontal coordinate values, 271 // respectively) are supported. 272 // 273 // For the cjk auto-hinter, the overshoot should be smaller than the 274 // reference for top zones, and vice versa for bottom zones. 275 // 276 // CJK_TOP 277 // Take the maximum flat and round coordinate values of the blue string 278 // characters. If not set, take the minimum values. 279 // 280 // CJK_RIGHT 281 // A synonym for CJK_TOP. If CJK_HORIZ is set, this flag indicates the 282 // right blue zone, taking horizontal maximum values. 283 // 284 // CJK_HORIZ 285 // Define a blue zone for horizontal hinting (i.e., vertical blue 286 // zones). If not set, this is a blue zone for vertical hinting. 287 288 289 AF_BLUE_STRINGSET_ENUM AF_BLUE_STRINGSETS_ARRAY AF_BLUE_STRINGSET_MAX_LEN: 290 291 AF_BLUE_STRINGSET_ARAB 292 { AF_BLUE_STRING_ARABIC_TOP, AF_BLUE_PROPERTY_LATIN_TOP } 293 { AF_BLUE_STRING_ARABIC_JOIN, 0 } 294 { AF_BLUE_STRING_MAX, 0 } 295 296 AF_BLUE_STRINGSET_CYRL 297 { AF_BLUE_STRING_CYRILLIC_CAPITAL_TOP, AF_BLUE_PROPERTY_LATIN_TOP } 298 { AF_BLUE_STRING_CYRILLIC_CAPITAL_BOTTOM, 0 } 299 { AF_BLUE_STRING_CYRILLIC_SMALL, AF_BLUE_PROPERTY_LATIN_TOP | 300 AF_BLUE_PROPERTY_LATIN_X_HEIGHT } 301 { AF_BLUE_STRING_CYRILLIC_SMALL, 0 } 302 { AF_BLUE_STRING_CYRILLIC_SMALL_DESCENDER, 0 } 303 { AF_BLUE_STRING_MAX, 0 } 304 305 AF_BLUE_STRINGSET_DEVA 306 { AF_BLUE_STRING_DEVANAGARI_TOP, AF_BLUE_PROPERTY_LATIN_TOP } 307 { AF_BLUE_STRING_DEVANAGARI_HEAD, AF_BLUE_PROPERTY_LATIN_TOP } 308 { AF_BLUE_STRING_DEVANAGARI_BASE, AF_BLUE_PROPERTY_LATIN_TOP | 309 AF_BLUE_PROPERTY_LATIN_NEUTRAL | 310 AF_BLUE_PROPERTY_LATIN_X_HEIGHT } 311 { AF_BLUE_STRING_DEVANAGARI_BASE, 0 } 312 { AF_BLUE_STRING_DEVANAGARI_BOTTOM, 0 } 313 { AF_BLUE_STRING_MAX, 0 } 314 315 AF_BLUE_STRINGSET_GREK 316 { AF_BLUE_STRING_GREEK_CAPITAL_TOP, AF_BLUE_PROPERTY_LATIN_TOP } 317 { AF_BLUE_STRING_GREEK_CAPITAL_BOTTOM, 0 } 318 { AF_BLUE_STRING_GREEK_SMALL_BETA_TOP, AF_BLUE_PROPERTY_LATIN_TOP } 319 { AF_BLUE_STRING_GREEK_SMALL, AF_BLUE_PROPERTY_LATIN_TOP | 320 AF_BLUE_PROPERTY_LATIN_X_HEIGHT } 321 { AF_BLUE_STRING_GREEK_SMALL, 0 } 322 { AF_BLUE_STRING_GREEK_SMALL_DESCENDER, 0 } 323 { AF_BLUE_STRING_MAX, 0 } 324 325 AF_BLUE_STRINGSET_HEBR 326 { AF_BLUE_STRING_HEBREW_TOP, AF_BLUE_PROPERTY_LATIN_TOP | 327 AF_BLUE_PROPERTY_LATIN_LONG } 328 { AF_BLUE_STRING_HEBREW_BOTTOM, 0 } 329 { AF_BLUE_STRING_HEBREW_DESCENDER, 0 } 330 { AF_BLUE_STRING_MAX, 0 } 331 332 AF_BLUE_STRINGSET_LATN 333 { AF_BLUE_STRING_LATIN_CAPITAL_TOP, AF_BLUE_PROPERTY_LATIN_TOP } 334 { AF_BLUE_STRING_LATIN_CAPITAL_BOTTOM, 0 } 335 { AF_BLUE_STRING_LATIN_SMALL_F_TOP, AF_BLUE_PROPERTY_LATIN_TOP } 336 { AF_BLUE_STRING_LATIN_SMALL, AF_BLUE_PROPERTY_LATIN_TOP | 337 AF_BLUE_PROPERTY_LATIN_X_HEIGHT } 338 { AF_BLUE_STRING_LATIN_SMALL, 0 } 339 { AF_BLUE_STRING_LATIN_SMALL_DESCENDER, 0 } 340 { AF_BLUE_STRING_MAX, 0 } 341 342 AF_BLUE_STRINGSET_TELU 343 { AF_BLUE_STRING_TELUGU_TOP, AF_BLUE_PROPERTY_LATIN_TOP } 344 { AF_BLUE_STRING_TELUGU_BOTTOM, 0 } 345 { AF_BLUE_STRING_MAX, 0 } 346 347 AF_BLUE_STRINGSET_THAI 348 { AF_BLUE_STRING_THAI_TOP, AF_BLUE_PROPERTY_LATIN_TOP | 349 AF_BLUE_PROPERTY_LATIN_X_HEIGHT } 350 { AF_BLUE_STRING_THAI_BOTTOM, 0 } 351 { AF_BLUE_STRING_THAI_ASCENDER, AF_BLUE_PROPERTY_LATIN_TOP } 352 { AF_BLUE_STRING_THAI_LARGE_ASCENDER, AF_BLUE_PROPERTY_LATIN_TOP } 353 { AF_BLUE_STRING_THAI_DESCENDER, 0 } 354 { AF_BLUE_STRING_THAI_LARGE_DESCENDER, 0 } 355 { AF_BLUE_STRING_THAI_DIGIT_TOP, 0 } 356 { AF_BLUE_STRING_MAX, 0 } 357 358 359 #ifdef AF_CONFIG_OPTION_CJK 360 361 AF_BLUE_STRINGSET_HANI 362 { AF_BLUE_STRING_CJK_TOP, AF_BLUE_PROPERTY_CJK_TOP } 363 { AF_BLUE_STRING_CJK_BOTTOM, 0 } 364 #ifdef AF_CONFIG_OPTION_CJK_BLUE_HANI_VERT 365 { AF_BLUE_STRING_CJK_LEFT, AF_BLUE_PROPERTY_CJK_HORIZ } 366 { AF_BLUE_STRING_CJK_RIGHT, AF_BLUE_PROPERTY_CJK_HORIZ | 367 AF_BLUE_PROPERTY_CJK_RIGHT } 368 #endif /* AF_CONFIG_OPTION_CJK_BLUE_HANI_VERT */ 369 { AF_BLUE_STRING_MAX, 0 } 370 371 #endif /* AF_CONFIG_OPTION_CJK */ 372 373 374 // END 375
