---
name: "Font::TTF::Kern"
section: "3pm"
platform: "linux"
package: "perl-font-ttf"
version: "1.06-6"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/Font::TTF::Kern"
---

# Font::TTF::Kern(3pm)

Kerning tables

## 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

- •

  Only supports kerning table types 0 & 2.

- •

  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.