font::ttf::gdef(3)
NAME
Font::TTF::Gdef - Opentype GDEF table support
DESCRIPTION
The GDEF table contains various global lists of informa
tion which are apparantly used in other places in an Open
Type renderer. But precisely where is open to specula
tion...
INSTANCE VARIABLES
There are 4 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 ele
- ment is an array of curve points corresponding
to the attachment points on that glyph. The
order of the curve points in the array corre
sponds to the attachment point number speci
fied in the MARKS coverage table (see below). - LIG This contains the ligature caret positioning informa
- tion for ligature glyphs
- COVERAGE
A coverage table to say which glyphs are liga
tures - 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 informa
tion 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
- Due to confusion in the GDEF specification, this field
is currently withdrawn until the confusion is
resolved. That way, perhaps this stuff will work! - This class definition table stores the mark attachment
point numbers for each attachment mark, to indicate
which attachment point the mark attaches to on its
base glyph.
METHODS
$t->read
Reads the table into the data structure
$t->out($fh)
- Writes out this table.