Font::TTF::Kern(3)    User Contributed Perl Documentation   Font::TTF::Kern(3)


NAME
       Font::TTF::Kern - Kerning tables

DESCRIPTION
       Kerning tables are held as an ordered collection of subtables each
       giving incremental information regarding the kerning of various pairs
       of glyphs.

       The basic structure of the kerning data structure is:

           $kern = $f->{'kern'}{'tables'}[$tnum]{'kerns'}{$leftnum}{$rightnum};

       Due to the possible complexity of some kerning tables the above
       information is insufficient. Reference also needs to be made to the
       type of the table and the coverage field.

INSTANCE VARIABLES
       The instance variables for a kerning table are relatively
       straightforward.

       Version
           Version number of the kerning table

       Num Number of subtables in the kerning table

       tables
           Array of subtables in the kerning table

           Each subtable has a number of instance variables.

           kern
               A two level hash array containing kerning values. The indexing
               is left is via left class and right class. It may seem using
               hashes is strange, but most tables are not type 2 and this
               method saves empty array values.

           type
               Stores the table type. Only type 0 and type 2 tables are
               specified for TrueType so far.

           coverage
               A bit field of coverage information regarding the kerning
               value. See the TrueType specification for details.

           Version
               Contains the version number of the table.

           Num Number of kerning pairs in this type 0 table.

           left
               An array indexed by glyph - left_first which returns a class
               number for the glyph in type 2 tables.

           right
               An array indexed by glyph - right_first which returns a class
               number for the glyph in type 2 tables.

           left_first
               the glyph number of the first element in the left array for
               type 2 tables.

           right_first
               the glyph number of the first element in the right array for
               type 2 tables.

           num_left
               Number of left classes

           num_right
               Number of right classes

METHODS
   $t->read
       Reads the whole kerning table into structures

   $t->out($fh)
       Outputs the kerning tables to the given file

   $t->XML_element($context, $depth, $key, $value)
       Handles outputting the kern hash into XML a little more tidily

   $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.

BUGS
       o   Only supports kerning table types 0 & 2.

       o   No real support functions to do anything with the kerning tables
           yet.

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.

perl v5.38.0                      2023-07-25                Font::TTF::Kern(3)