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 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 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
- 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currently withdrawn until the confusion is resolved.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.
