#======================================================================= # ____ ____ _____ _ ____ ___ ____ # | _ \| _ \| ___| _ _ / \ | _ \_ _| |___ \ # | |_) | | | | |_ (_) (_) / _ \ | |_) | | __) | # | __/| |_| | _| _ _ / ___ \| __/| | / __/ # |_| |____/|_| (_) (_) /_/ \_\_| |___| |_____| # # A Perl Module Chain to faciliate the Creation and Modification # of High-Quality "Portable Document Format (PDF)" Files. # #======================================================================= # # THIS IS A REUSED PERL MODULE, FOR PROPER LICENCING TERMS SEE BELOW: # # # Copyright Martin Hosken <Martin_Hosken@sil.org> # # No warranty or expression of effectiveness, least of all regarding # anyone's safety, is implied in this software or documentation. # # This specific module is licensed under the Perl Artistic License. # # # $Id: Kern.pm,v 1.5 2004/06/15 09:13:37 fredo Exp $ # #======================================================================= package PDF::API2::Basic::TTF::Kern; =head1 NAME PDF::API2::Basic::TTF::Kern - Kerning tables =head1 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. =head1 INSTANCE VARIABLES The instance variables for a kerning table are relatively straightforward. =over 4 =item Version Version number of the kerning table =item Num Number of subtables in the kerning table =item tables Array of subtables in the kerning table =over 4 Each subtable has a number of instance variables. =item kern A two level hash array containing kerning values. The indexing is left value and then right value. In the case of type 2 tables, the indexing 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. =item type Stores the table type. Only type 0 and type 2 tables are specified for TrueType so far. =item coverage A bit field of coverage information regarding the kerning value. See the TrueType specification for details. =item Version Contains the version number of the table. =item Num Number of kerning pairs in this type 0 table. =item left An array indexed by glyph - left_first which returns a class number for the glyph in type 2 tables. =item right An array indexed by glyph - right_first which returns a class number for the glyph in type 2 tables. =item left_first the glyph number of the first element in the left array for type 2 tables. =item right_first the glyph number of the first element in the right array for type 2 tables. =item num_left Number of left classes =item num_right Number of right classes =back =back =head1 METHODS =cut use strict; use vars qw(@ISA); use PDF::API2::Basic::TTF::Utils; use PDF::API2::Basic::TTF::Table; @ISA = qw(PDF::API2::Basic::TTF::Table); =head2 $t->read Reads the whole kerning table into structures =cut sub read { my ($self) = @_; my ($fh) = $self->{' INFILE'}; my ($dat, $i, $numt, $len, $cov, $t); $self->SUPER::read or return $self; $fh->read($dat, 4); ($self->{'Version'}, $numt) = unpack("n2", $dat); $self->{'Num'} = $numt; for ($i = 0; $i < $numt; $i++) { $t = {}; $fh->read($dat, 6); ($t->{'Version'}, $len, $cov) = unpack("n3", $dat); $t->{'coverage'} = $cov & 255; $t->{'type'} = $cov >> 8; $fh->read($dat, $len - 6); if ($t->{'Version'} == 0) { my ($j); $t->{'Num'} = unpack("n", $dat); for ($j = 0; $j < $t->{'Num'}; $j++) { my ($f, $l, $v) = TTF_Unpack("SSs", substr($dat, $j * 6 + 8, 6)); $t->{'kern'}{$f}{$l} = $v; } } elsif ($t->{'Version'} == 2) { my ($wid, $off, $numg, $maxl, $maxr, $j); $wid = unpack("n", $dat); $off = unpack("n", substr($dat, 2)); ($t->{'left_first'}, $numg) = unpack("n2", substr($dat, $off)); $t->{'left'} = [unpack("C$numg", substr($dat, $off + 4))]; foreach (@{$t->{'left'}}) { $_ /= $wid; $maxl = $_ if ($_ > $maxl); } $t->{'left_max'} = $maxl; $off = unpack("n", substr($dat, 4)); ($t->{'right_first'}, $numg) = unpack("n2", substr($dat, $off)); $t->{'right'} = [unpack("C$numg", substr($dat, $off + 4))]; foreach (@{$t->{'right'}}) { $_ >>= 1; $maxr = $_ if ($_ > $maxr); } $t->{'right_max'} = $maxr; $off = unpack("n", substr($dat, 6)); for ($j = 0; $j <= $maxl; $j++) { my ($k) = 0; map { $t->{'kern'}{$j}{$k} = $_ if $_; $k++; } unpack("n$maxr", substr($dat, $off + $wid * $j)); } } push (@{$self->{'tables'}}, $t); } $self; } =head2 $t->out($fh) Outputs the kerning tables to the given file =cut sub out { my ($self, $fh) = @_; my ($i, $l, $r, $loc, $loc1, $t); return $self->SUPER::out($fh) unless ($self->{' read'}); $fh->print(pack("n2", $self->{'Version'}, $self->{'Num'})); for ($i = 0; $i < $self->{'Num'}; $i++) { $t = $self->{'tables'}[$i]; $loc = $fh->tell(); $fh->print(pack("nnn", $t->{'Version'}, 0, $t->{'coverage'})); if ($t->{'Version'} == 0) { my ($dat); foreach $l (sort {$a <=> $b} keys %{$t->{'kern'}}) { foreach $r (sort {$a <=> $b} keys %{$t->{'kern'}{$l}}) { $dat .= TTF_Pack("SSs", $l, $r, $t->{'kern'}{$l}{$r}); } } $fh->print(TTF_Pack("SSSS", PDF::API2::Basic::TTF::Utils::TTF_bininfo(length($dat) / 6, 6))); $fh->print($dat); } elsif ($t->{'Version'} == 2) { my ($arr); $fh->print(pack("nnnn", $t->{'right_max'} << 1, 8, ($#{$t->{'left'}} + 7) << 1, ($#{$t->{'left'}} + $#{$t->{'right'}} + 10) << 1)); $fh->print(pack("nn", $t->{'left_first'}, $#{$t->{'left'}} + 1)); foreach (@{$t->{'left'}}) { $fh->print(pack("C", $_ * (($t->{'left_max'} + 1) << 1))); } $fh->print(pack("nn", $t->{'right_first'}, $#{$t->{'right'}} + 1)); foreach (@{$t->{'right'}}) { $fh->print(pack("C", $_ << 1)); } $arr = "\000\000" x (($t->{'left_max'} + 1) * ($t->{'right_max'} + 1)); foreach $l (keys %{$t->{'kern'}}) { foreach $r (keys %{$t->{'kern'}{$l}}) { substr($arr, ($l * ($t->{'left_max'} + 1) + $r) << 1, 2) = pack("n", $t->{'kern'}{$l}{$r}); } } $fh->print($arr); } $loc1 = $fh->tell(); $fh->seek($loc + 2, 0); $fh->print(pack("n", $loc1 - $loc)); $fh->seek($loc1, 0); } $self; } =head2 $t->XML_element($context, $depth, $key, $value) Handles outputting the kern hash into XML a little more tidily =cut sub XML_element { my ($self) = shift; my ($context, $depth, $key, $value) = @_; my ($fh) = $context->{'fh'}; my ($f, $l); return $self->SUPER::XML_element(@_) unless ($key eq 'kern'); $fh->print("$depth<kern-table>\n"); foreach $f (sort {$a <=> $b} keys %{$value}) { foreach $l (sort {$a <=> $b} keys %{$value->{$f}}) { $fh->print("$depth$context->{'indent'}<adjust first='$f' last='$l' dist='$value->{$f}{$l}'/>\n"); } } $fh->print("$depth</kern-table>\n"); $self; } 1; =head1 BUGS =over 4 =item * Only supports kerning table types 0 & 2. =item * No real support functions to I<do> anything with the kerning tables yet. =back =head1 AUTHOR Martin Hosken Martin_Hosken@sil.org. See L<PDF::API2::Basic::TTF::Font> for copyright and licensing. =cut