Font::TTF::GDEF - Opentype GDEF table support
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...
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.
Reads the table into the data structure
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.
Martin Hosken <http://scripts.sil.org/FontUtils>.
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.