/usr/bin/make_gdl

NAME
    make_gdl - Create GDL from a TrueType Font

SYNOPSIS
      make_gdl [-a file] [-i file] [-l type [-s num]] [-n num] [-z bitfield]
               infile outfile
      make_gdl -h
    Creates font specific GDL from a font and optional attachment point database

OPTIONS
      -a file       Attachment point database
      -c classfile  xml file of class and property information to merge in
      --classprops  specifies whether classes are made for property values in
                    the classfile
      --classwarn   issue warnings if classfile contains references to glyphs
                    that are not in the font.
      --autodefines Output per class #defines for key classes
      -d name=val   Add #defines to output gdl
      -e file       A file containing names (1 per line) of glyphs that are
                    known to have no outline (thus shouldn't generate warnings).
      -h            print manpage
      -i file       add #include statement at end of file
      -l type       type =
                        first - class name is first code, contents other codes
                        last  - class name is last code, contents other codes
                        firstcomp - treat extensions as part of elements, as first
                        lastcomp - treat extensions as part of elements, as last
      -m "list"     List of APs to ignore when deciding whether a glyph is a mark
      -n num        Add a normalization substitution with the given pass number
      -o "list"     List of AP names to omit
      --package file
                    Use the named file instead of Font::TTF::Scripts::GDL.pm to
                    open the font. Assumes the internal package name is the
                    same as the basename of file (sans any extension).
      -p num        Add auto positioning attachment rules with the given pass number
      -r            Rename point names such that final M gets initial _ and final S
                    is removed. Typically for Fontographer fonts.
      -s num        Add ligature substitution rules with the given pass number
      -z bitfield   Bitfield of various controls:
                        0 - use component properties to set ligature bounding boxes
                        1 - normalise even if presentation is only references
                        2 - use postscript names in glyph definitions

DESCRIPTION
    When writing a GDL description for a font there are generally two parts
    to such a description. The first part is a general behaviour description
    that is appropriate to a number of fonts for a particular writing
    system. It will contain rules for reordering, substitution, positioning,
    etc and is often written in terms of classes rather than individual
    glyphs. For a very simple script such a description may be empty.

    The second part of a description is font specific and includes names of
    glyphs positions of attachment points and other properties for each
    glyph. It will also contain class definitions and perhaps even some
    glyph specific rules.

    It is this second part that make_gdl is designed to address. Make_gdl
    will take a TTF and perhaps an attachment point database (defined in
    ttfbuilder) and will create a standardised font specific GDL description
    which may or may not be sufficient to describe the behaviour of the
    font. It is more likely that a general behaviour file will also need to
    be written.

    The generated GDL consists of 4 sections:

  Glyph Definitions
    Each glyph has a definition as part of a table(glyph) section. The name
    of the glyph is based on the postscript name of the glyph. If the name
    is of the form of a general Unicode character in the Adobe Glyph List,
    then the name is transformed with an initial "g_" followed by the
    unicode USV. If there is a sequence of unicode values in the name, the
    "uni" parts of the name are replaced by <_> resulting in something like:
    "g_1000_103c". Otherwise the name is transformed to lower case with each
    upper case letter preceded by "_" and the name preceded by "g_" as in
    "g__a" for A. If a glyph has a variant ("."var) the "." is turned into
    "_". If a glyph is multinamed (separated by "/") then only the first
    name is used for the glyph name although the glyph will appear in all
    the classes appropriate to all its names.

    Glyphs may have attachment points and these come from the attachment
    points database given on the command line. In addition any properties
    with the name starting "GDL_" are included as glyph attributes for use
    in rules. Ligature components may also propagate from the attachment
    point database.

    Attachment points are assumed to be named according to the Fontlab
    convention whereby a diacritic has an anchor named "_"x that is anchored
    to a base character on the attachment point x. The names of the se
    attachment points are munged so that "_"x becomes "xM" and x becomes
    x"S".

  Class Definitions
    For each attachment point base name (x) a class is created. Class
    "c"x"Dia" contains a list of all the glyphs with the attachment point
    "_"x. Class "cTakes"x"Dia" contains all the glyphs with attachment point
    x. Class "cn"x"Dia" contains all the glyphs without attachment point
    "_"X. And the class "cnTakes"x"Dia" contains all the glyphs without the
    x attachment point.

    In addition for each glyph name variant (as labelled in a postscript
    name for a glyph using "."var) a class named "c"var is created with all
    the glyphs with that variant in their name. A class named "cno_"var is
    also created containing all the corresponding glyphs without the
    variant, in direct correspondance, so that the non-variant form may be
    mapped to the variant form using a single rule, for all the glyphs in
    the class.

    Finally a class is created for ligature components. If a glyph is part
    of a ligature rule it is either the key glyph for the rule or part of
    the class for the rule. Thus for a rule keyed of a glyph named x there
    will be two classes: "clig_"x which is the ligatures involving x and
    "cligno_"x which contains all the components that correspond to the
    ligatures found in the other class. This makes a ligature rule a simple
    2:1 mapping from "cligno_"x + key to "clig_"x.

  Rules
    Make_gdl may also create generalised rules to simplify the creation of
    GDL descriptions. Which rule sets are generated is controlled from the
    command line.

    If the "-n" command line option is used, make_gdl will create
    normalisation rules. These rules will map any glyph sequence that
    corresponds to a unicode sequence that has a canonical composition that
    exists in the font into that glyph.

    If the "-s" command line option is used, make_gdl will write rules for
    combining glyphs into ligatures according to the glyph naming in the
    postscript name table. Ligature rules are based on a class and a glyph.
    By default the class contains a list of first glyphs in a ligature pair
    and there is a rule for each second glyph. If "-l last" is used then
    this is reversed with there being a rule for each first glyph and the
    second glyph is in a class. If variants are involved, should the name be
    a variant of the ligature or the last glyph in the ligature sequence? If
    "-l firstcomp" or "-l lastcomp" then then variant is considered part of
    the last glyph otherwise it is considered part of the ligature.

  Inclusion
    make_gdl outputs a preprocessor definition "MAXGLYPH" that is set to the
    number of glyphs in the font.

    Since a GDL description is only a single file, the command line allows
    one to specify another GDL file to include at the end of the file. This
    makes including a font independent GDL fragment much easier.

  Classfile
    The DTD for the classes file is:

        <!ELEMENT classes (class, property)*>

        <!ELEMENT class (#PCDATA)>
        <!ATTLIST class
            name    CDATA #REQUIRED
            exts    CDATA #IMPLIED>

        <!ELEMENT property (#PCDATA)>
        <!ATTLIST property
            name    CDATA #REQUIRED
            value   CDATA #REQUIRED
            exts    CDATA #IMPLIED>

SEE ALSO
    ttfbuilder

AUTHOR
    Martin Hosken <http://scripts.sil.org/FontUtils>. (see CONTRIBUTORS for
    other authors).

LICENSING
    Copyright (c) 1998-2016, SIL International (http://www.sil.org)

    This script is released under the terms of the Artistic License 2.0. For
    details, see the full text of the license in the file LICENSE.