lib/tablue.dat

   1 //  tablue.dat
   2 //
   3 //    Auto-fitter data for blue strings.
   4 //
   5 // Copyright (C) 2013-2014 by Werner Lemberg.
   6 //
   7 // This file is part of the ttfautohint library, and may only be used,
   8 // modified, and distributed under the terms given in `COPYING'.  By
   9 // continuing to use, modify, or distribute this file you indicate that you
  10 // have read `COPYING' and understand and accept it fully.
  11 //
  12 // The file `COPYING' mentioned in the previous paragraph is distributed
  13 // with the ttfautohint library.
  14
  15 // originally file `afblue.dat' (2013-Sep-22) from FreeType */
  16
  17
  18 // This file contains data specific to blue zones.  It gets processed by
  19 // a script to simulate `jagged arrays', with enumeration values holding
  20 // offsets into the arrays.
  21 //
  22 // The format of the file is rather simple:  A section starts with three
  23 // labels separated by whitespace and followed by a colon (everything in a
  24 // single line); the first label gives the name of the enumeration template,
  25 // the second the name of the array template, and the third the name of the
  26 // `maximum' template, holding the size of the largest array element.  The
  27 // script then fills the corresponding templates (indicated by `@'
  28 // characters around the name).
  29 //
  30 // A section contains one or more data records.  Each data record consists
  31 // of two or more lines.  The first line holds the enumeration name, and the
  32 // remaining lines the corresponding array data.
  33 //
  34 // There are two possible representations for array data.
  35 //
  36 // - A string of characters in UTF-8 encoding enclosed in double quotes,
  37 //   using C syntax.  There can be only one string per line, thus the
  38 //   starting and ending double quote must be the first and last character
  39 //   in the line, respectively, ignoring whitespace before and after the
  40 //   string.  Space characters within the string are ignored too.  If there
  41 //   are multiple strings (in multiple lines), they are concatenated to a
  42 //   single string.  In the output, a string gets represented as a series of
  43 //   singles bytes, followed by a zero byte.  The enumeration values simply
  44 //   hold byte offsets to the start of the corresponding strings.
  45 //
  46 // - Data blocks enclosed in balanced braces, which get copied verbatim and
  47 //   which can span multiple lines.  The opening brace of a block must be
  48 //   the first character of a line (ignoring whitespace), and the closing
  49 //   brace the last (ignoring whitespace also).  The script appends a comma
  50 //   character after each block and counts the number of blocks to set the
  51 //   enumeration values.
  52 //
  53 // A section can contain either strings only or data blocks only.
  54 //
  55 // A comment line starts with `//'; it gets removed.  A preprocessor
  56 // directive line (using the standard syntax of `cpp') starts with `#' and
  57 // gets copied verbatim to both the enumeration and the array.  Whitespace
  58 // outside of a string is insignificant.
  59 //
  60 // Preprocessor directives are ignored while the script computes maximum
  61 // values; this essentially means that the maximum values can easily be too
  62 // large.  Given that the purpose of those values is to create local
  63 // fixed-size arrays at compile time for further processing of the blue zone
  64 // data, this isn't a problem.  Note the the final zero byte of a string is
  65 // not counted.  Note also that the count holds the number of UTF-8 encoded
  66 // characters, not bytes.
  67
  68
  69 // The blue zone string data, to be used in the blue stringsets below.
  70
  71 TA_BLUE_STRING_ENUM TA_BLUE_STRINGS_ARRAY TA_BLUE_STRING_MAX_LEN:
  72
  73   TA_BLUE_STRING_CYRILLIC_CAPITAL_TOP
  74     "БВЕПЗОСЭ"
  75   TA_BLUE_STRING_CYRILLIC_CAPITAL_BOTTOM
  76     "БВЕШЗОСЭ"
  77   TA_BLUE_STRING_CYRILLIC_SMALL
  78     "хпншезос"
  79   TA_BLUE_STRING_CYRILLIC_SMALL_DESCENDER
  80     "руф"
  81
  82   // we separate the letters with spaces to avoid ligatures;
  83   // this is just for convenience to simplify reading
  84   TA_BLUE_STRING_DEVANAGARI_BASE
  85     "क न म उ छ ट ठ ड"
  86   TA_BLUE_STRING_DEVANAGARI_TOP
  87     "ई ऐ ओ औ ि ी ो ौ"
  88   // note that some fonts have extreme variation in the height of the
  89   // round head elements; for this reason we also define the `base'
  90   // blue zone, which must be always present
  91   TA_BLUE_STRING_DEVANAGARI_HEAD
  92     "क म अ आ थ ध भ श"
  93   TA_BLUE_STRING_DEVANAGARI_BOTTOM
  94     "ु ृ"
  95
  96   TA_BLUE_STRING_GREEK_CAPITAL_TOP
  97     "ΓΒΕΖΘΟΩ"
  98   TA_BLUE_STRING_GREEK_CAPITAL_BOTTOM
  99     "ΒΔΖΞΘΟ"
 100   TA_BLUE_STRING_GREEK_SMALL_BETA_TOP
 101     "βθδζλξ"
 102   TA_BLUE_STRING_GREEK_SMALL
 103     "αειοπστω"
 104   TA_BLUE_STRING_GREEK_SMALL_DESCENDER
 105     "βγημρφχψ"
 106
 107   TA_BLUE_STRING_HEBREW_TOP
 108     "בדהחךכםס"
 109   TA_BLUE_STRING_HEBREW_BOTTOM
 110     "בטכםסצ"
 111   TA_BLUE_STRING_HEBREW_DESCENDER
 112     "קךןףץ"
 113
 114   TA_BLUE_STRING_LATIN_CAPITAL_TOP
 115     "THEZOCQS"
 116   TA_BLUE_STRING_LATIN_CAPITAL_BOTTOM
 117     "HEZLOCUS"
 118   TA_BLUE_STRING_LATIN_SMALL_F_TOP
 119     "fijkdbh"
 120   TA_BLUE_STRING_LATIN_SMALL
 121     "xzroesc"
 122   TA_BLUE_STRING_LATIN_SMALL_DESCENDER
 123     "pqgjy"
 124
 125
 126 // The blue zone stringsets, as used in the script styles, cf. `tastyles.h'.
 127 //
 128 // The TA_BLUE_PROPERTY_XXX flags are defined in `tablue.h'; here some
 129 // explanations.
 130 //
 131 // A blue zone in general is defined by a reference and an overshoot line.
 132 // During the hinting process, all coordinate values between those two lines
 133 // are set equal to the reference value, provided that the blue zone is not
 134 // wider than 0.75 pixels (otherwise the blue zone gets ignored).  All
 135 // entries must have `TA_BLUE_STRING_MAX' as the final line.
 136 //
 137 // During the glyph analysis, edges are sorted from bottom to top, and then
 138 // sequentially checked, edge by edge, against the blue zones in the order
 139 // given below.
 140 //
 141 //
 142 // latin auto-hinter
 143 // -----------------
 144 //
 145 // Characters in a blue string are automatically classified as having a flat
 146 // (reference) or a round (overshoot) extremum.  The blue zone is then set
 147 // up by the mean values of all flat extrema and all round extrema,
 148 // respectively.  Only horizontal blue zones (i.e., adjusting vertical
 149 // coordinate values) are supported.
 150 //
 151 // For the latin auto-hinter, the overshoot should be larger than the
 152 // reference for top zones, and vice versa for bottom zones.
 153 //
 154 //   LATIN_TOP
 155 //     Take the maximum flat and round coordinate values of the blue string
 156 //     characters for computing the blue zone's reference and overshoot
 157 //     values.
 158 //
 159 //     If not set, take the minimum values.
 160 //
 161 //   LATIN_NEUTRAL
 162 //     Ignore round extrema and define the blue zone with flat values only.
 163 //     Both top and bottom of contours can match.  This is useful for
 164 //     scripts like Devanagari where vowel signs attach to the base
 165 //     character and are implemented as components of composite glyphs.
 166 //
 167 //     If not set, both round and flat extrema are taken into account.
 168 //     Additionally, only the top or the bottom of a contour can match,
 169 //     depending on the LATIN_TOP flag.
 170 //
 171 //     Neutral blue zones should always follow non-neutral blue zones.
 172 //
 173 //   LATIN_X_HEIGHT
 174 //     Scale all glyphs vertically from the corresponding script to make the
 175 //     reference line of this blue zone align on the grid.  The scaling
 176 //     takes place before all other blue zones get aligned to the grid.
 177 //     Only one blue character string of a script style can have this flag.
 178 //
 179 //   LATIN_LONG
 180 //     Apply an additional constraint for blue zone values: Don't
 181 //     necessarily use the extremum as-is but a segment of the topmost (or
 182 //     bottommost) contour that is longer than a heuristic threshold, and
 183 //     which is not too far away vertically from the real extremum.  This
 184 //     ensures that small bumps in the outline are ignored (for example, the
 185 //     `vertical serifs' found in many Hebrew glyph designs).
 186 //
 187 //     The segment must be at least EM/25 font units long, and the distance
 188 //     to the extremum must be smaller than EM/4.
 189
 190
 191 TA_BLUE_STRINGSET_ENUM TA_BLUE_STRINGSETS_ARRAY TA_BLUE_STRINGSET_MAX_LEN:
 192
 193   TA_BLUE_STRINGSET_CYRL
 194     { TA_BLUE_STRING_CYRILLIC_CAPITAL_TOP,     TA_BLUE_PROPERTY_LATIN_TOP        }
 195     { TA_BLUE_STRING_CYRILLIC_CAPITAL_BOTTOM,  0                                 }
 196     { TA_BLUE_STRING_CYRILLIC_SMALL,           TA_BLUE_PROPERTY_LATIN_TOP      |
 197                                                TA_BLUE_PROPERTY_LATIN_X_HEIGHT   }
 198     { TA_BLUE_STRING_CYRILLIC_SMALL,           0                                 }
 199     { TA_BLUE_STRING_CYRILLIC_SMALL_DESCENDER, 0                                 }
 200     { TA_BLUE_STRING_MAX,                      0                                 }
 201
 202   TA_BLUE_STRINGSET_DEVA
 203     { TA_BLUE_STRING_DEVANAGARI_TOP,    TA_BLUE_PROPERTY_LATIN_TOP        }
 204     { TA_BLUE_STRING_DEVANAGARI_HEAD,   TA_BLUE_PROPERTY_LATIN_TOP        }
 205     { TA_BLUE_STRING_DEVANAGARI_BASE,   TA_BLUE_PROPERTY_LATIN_TOP      |
 206                                         TA_BLUE_PROPERTY_LATIN_NEUTRAL  |
 207                                         TA_BLUE_PROPERTY_LATIN_X_HEIGHT   }
 208     { TA_BLUE_STRING_DEVANAGARI_BASE,   0                                 }
 209     { TA_BLUE_STRING_DEVANAGARI_BOTTOM, 0                                 }
 210     { TA_BLUE_STRING_MAX,               0                                 }
 211
 212   TA_BLUE_STRINGSET_GREK
 213     { TA_BLUE_STRING_GREEK_CAPITAL_TOP,     TA_BLUE_PROPERTY_LATIN_TOP        }
 214     { TA_BLUE_STRING_GREEK_CAPITAL_BOTTOM,  0                                 }
 215     { TA_BLUE_STRING_GREEK_SMALL_BETA_TOP,  TA_BLUE_PROPERTY_LATIN_TOP        }
 216     { TA_BLUE_STRING_GREEK_SMALL,           TA_BLUE_PROPERTY_LATIN_TOP      |
 217                                             TA_BLUE_PROPERTY_LATIN_X_HEIGHT   }
 218     { TA_BLUE_STRING_GREEK_SMALL,           0                                 }
 219     { TA_BLUE_STRING_GREEK_SMALL_DESCENDER, 0                                 }
 220     { TA_BLUE_STRING_MAX,                   0                                 }
 221
 222   TA_BLUE_STRINGSET_HEBR
 223     { TA_BLUE_STRING_HEBREW_TOP,       TA_BLUE_PROPERTY_LATIN_TOP  |
 224                                        TA_BLUE_PROPERTY_LATIN_LONG   }
 225     { TA_BLUE_STRING_HEBREW_BOTTOM,    0                             }
 226     { TA_BLUE_STRING_HEBREW_DESCENDER, 0                             }
 227     { TA_BLUE_STRING_MAX,              0                             }
 228
 229   TA_BLUE_STRINGSET_LATN
 230     { TA_BLUE_STRING_LATIN_CAPITAL_TOP,     TA_BLUE_PROPERTY_LATIN_TOP        }
 231     { TA_BLUE_STRING_LATIN_CAPITAL_BOTTOM,  0                                 }
 232     { TA_BLUE_STRING_LATIN_SMALL_F_TOP,     TA_BLUE_PROPERTY_LATIN_TOP        }
 233     { TA_BLUE_STRING_LATIN_SMALL,           TA_BLUE_PROPERTY_LATIN_TOP      |
 234                                             TA_BLUE_PROPERTY_LATIN_X_HEIGHT   }
 235     { TA_BLUE_STRING_LATIN_SMALL,           0                                 }
 236     { TA_BLUE_STRING_LATIN_SMALL_DESCENDER, 0                                 }
 237     { TA_BLUE_STRING_MAX,                   0                                 }
 238
 239 // END