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
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37               A two level hash array containing kerning values. The indexing
38               is left value and then right value. In the case of type 2
39               tables, the indexing is via left class and right class. It may
40               seem using hashes is strange, but most tables are not type 2
41               and this method saves empty array values.
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43               type
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45               Stores the table type. Only type 0 and type 2 tables are
46               specified for TrueType so far.
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48               coverage
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50               A bit field of coverage information regarding the kerning
51               value. See the TrueType specification for details.
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53               Version
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55               Contains the version number of the table.
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57               Num
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59               Number of kerning pairs in this type 0 table.
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61               left
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63               An array indexed by glyph - left_first which returns a class
64               number for the glyph in type 2 tables.
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66               right
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68               An array indexed by glyph - right_first which returns a class
69               number for the glyph in type 2 tables.
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71               left_first
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73               the glyph number of the first element in the left array for
74               type 2 tables.
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76               right_first
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78               the glyph number of the first element in the right array for
79               type 2 tables.
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81               num_left
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83               Number of left classes
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85               num_right
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87               Number of right classes
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METHODS

90   $t->read
91       Reads the whole kerning table into structures
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93   $t->out($fh)
94       Outputs the kerning tables to the given file
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96   $t->XML_element($context, $depth, $key, $value)
97       Handles outputting the kern hash into XML a little more tidily
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BUGS

100       ·   Only supports kerning table types 0 & 2.
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102       ·   No real support functions to do anything with the kerning tables
103           yet.
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AUTHOR

106       Martin Hosken Martin_Hosken@sil.org. See Font::TTF::Font for copyright
107       and licensing.
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POD ERRORS

110       Hey! The above document had some coding errors, which are explained
111       below:
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113       Around line 38:
114           You can't have =items (as at line 42) unless the first thing after
115           the =over is an =item
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119perl v5.10.1                      2008-06-11                Font::TTF::Kern(3)