NAME

       Font::TTF::GDEF - Opentype GDEF table support

DESCRIPTION

       The GDEF table contains various global lists of information which are apparantly used in
       other places in an OpenType renderer. But precisely where is open to speculation...

INSTANCE VARIABLES

       There are up to 5 tables in the GDEF table, each with their own structure:

       GLYPH
           This is an Font::TTF::Coverage Class Definition table containing information as to
           what type each glyph is.

       ATTACH
           The attach table consists of a coverage table and then attachment points for each
           glyph in the coverage table:

           COVERAGE
                   This is a coverage table

           POINTS  This is an array of point elements. Each element is an array of curve points
                   corresponding to the attachment points on that glyph. The order of the curve
                   points in the array corresponds to the attachment point number specified in
                   the MARKS coverage table (see below).

       LIG This contains the ligature caret positioning information for ligature glyphs

           COVERAGE
                   A coverage table to say which glyphs are ligatures

           LIGS    An array of elements for each ligature. Each element is an array of
                   information for each caret position in the ligature (there being number of
                   components - 1 of these, generally)

                   FMT         This is the format of the information and is important to provide
                               the semantics for the value. This value must be set correctly
                               before output

                   VAL         The value which has meaning according to FMT

                   DEVICE      For FMT = 3, a device table is also referenced which is stored
                               here

       MARKS
           This class definition table defines the classes of mark glyphs that can be selected
           for processing using the MarkAttachmentType field of lookup FLAG words.

       MARKSETS
           Contains an array of coverage tables indexed by the FILTER value of a lookup.

METHODS

   $t->read
       Reads the table into the data structure

   $t->out($fh)
       Writes out this table.

   $t->minsize()
       Returns the minimum size this table can be. If it is smaller than this, then the table
       must be bad and should be deleted or whatever.

   $t->update
       Sort COVERAGE tables.

AUTHOR

       Martin Hosken <http://scripts.sil.org/FontUtils>.

LICENSING

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

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