1Font::TTF::Kern(3)    User Contributed Perl Documentation   Font::TTF::Kern(3)
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NAME

6       Font::TTF::Kern - Kerning tables
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DESCRIPTION

9       Kerning tables are held as an ordered collection of subtables each
10       giving incremental information regarding the kerning of various pairs
11       of glyphs.
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13       The basic structure of the kerning data structure is:
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15           $kern = $f->{'kern'}{'tables'}[$tnum]{'kerns'}{$leftnum}{$rightnum};
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17       Due to the possible complexity of some kerning tables the above
18       information is insufficient. Reference also needs to be made to the
19       type of the table and the coverage field.
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INSTANCE VARIABLES

22       The instance variables for a kerning table are relatively
23       straightforward.
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25       Version
26           Version number of the kerning table
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28       Num Number of subtables in the kerning table
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30       tables
31           Array of subtables in the kerning table
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33           Each subtable has a number of instance variables.
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35           kern
36               A two level hash array containing kerning values. The indexing
37               is left is via left class and right class. It may seem using
38               hashes is strange, but most tables are not type 2 and this
39               method saves empty array values.
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41           type
42               Stores the table type. Only type 0 and type 2 tables are
43               specified for TrueType so far.
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45           coverage
46               A bit field of coverage information regarding the kerning
47               value. See the TrueType specification for details.
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49           Version
50               Contains the version number of the table.
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52           Num Number of kerning pairs in this type 0 table.
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54           left
55               An array indexed by glyph - left_first which returns a class
56               number for the glyph in type 2 tables.
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58           right
59               An array indexed by glyph - right_first which returns a class
60               number for the glyph in type 2 tables.
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62           left_first
63               the glyph number of the first element in the left array for
64               type 2 tables.
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66           right_first
67               the glyph number of the first element in the right array for
68               type 2 tables.
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70           num_left
71               Number of left classes
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73           num_right
74               Number of right classes
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METHODS

77   $t->read
78       Reads the whole kerning table into structures
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80   $t->out($fh)
81       Outputs the kerning tables to the given file
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83   $t->XML_element($context, $depth, $key, $value)
84       Handles outputting the kern hash into XML a little more tidily
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86   $t->minsize()
87       Returns the minimum size this table can be. If it is smaller than this,
88       then the table must be bad and should be deleted or whatever.
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BUGS

91       •   Only supports kerning table types 0 & 2.
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93       •   No real support functions to do anything with the kerning tables
94           yet.
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AUTHOR

97       Martin Hosken <http://scripts.sil.org/FontUtils>.
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LICENSING

100       Copyright (c) 1998-2016, SIL International (http://www.sil.org)
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102       This module is released under the terms of the Artistic License 2.0.
103       For details, see the full text of the license in the file LICENSE.
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107perl v5.36.0                      2023-01-20                Font::TTF::Kern(3)
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