--- /dev/null
+package Font::TTF::Vhea;
+
+=head1 NAME
+
+Font::TTF::Vhea - Vertical Header table
+
+=head1 DESCRIPTION
+
+This is a simple table with just standards specified instance variables
+
+=head1 INSTANCE VARIABLES
+
+ version
+ Ascender
+ Descender
+ LineGap
+ advanceHeightMax
+ minTopSideBearing
+ minBottomSideBearing
+ yMaxExtent
+ caretSlopeRise
+ caretSlopeRun
+ metricDataFormat
+ numberOfVMetrics
+
+
+=head1 METHODS
+
+=cut
+
+use strict;
+use vars qw(@ISA %fields @field_info);
+
+require Font::TTF::Table;
+use Font::TTF::Utils;
+
+@ISA = qw(Font::TTF::Table);
+@field_info = (
+ 'version' => 'v',
+ 'Ascender' => 's',
+ 'Descender' => 's',
+ 'LineGap' => 's',
+ 'advanceHeightMax' => 'S',
+ 'minTopSideBearing' => 's',
+ 'minBottomSideBearing' => 's',
+ 'yMaxExtent' => 's',
+ 'caretSlopeRise' => 's',
+ 'caretSlopeRun' => 's',
+ 'metricDataFormat' => '+10s',
+ 'numberOfVMetrics' => 's');
+
+sub init
+{
+ my ($k, $v, $c, $i);
+ for ($i = 0; $i < $#field_info; $i += 2)
+ {
+ ($k, $v, $c) = TTF_Init_Fields($field_info[$i], $c, $field_info[$i + 1]);
+ next unless defined $k && $k ne "";
+ $fields{$k} = $v;
+ }
+}
+
+
+=head2 $t->read
+
+Reads the table into memory as instance variables
+
+=cut
+
+sub read
+{
+ my ($self) = @_;
+ my ($dat);
+
+ $self->SUPER::read or return $self;
+ init unless defined $fields{'Ascender'};
+ $self->{' INFILE'}->read($dat, 36);
+
+ TTF_Read_Fields($self, $dat, \%fields);
+ $self;
+}
+
+
+=head2 $t->out($fh)
+
+Writes the table to a file either from memory or by copying.
+
+=cut
+
+sub out
+{
+ my ($self, $fh) = @_;
+
+ return $self->SUPER::out($fh) unless $self->{' read'};
+
+ $self->{'numberOfVMetrics'} = $self->{' PARENT'}{'vmtx'}->numMetrics || $self->{'numberOfVMetrics'};
+ $fh->print(TTF_Out_Fields($self, \%fields, 36));
+ $self;
+}
+
+
+=head2 $t->update
+
+Updates various parameters in the hhea table from the hmtx table, assuming
+the C<hmtx> table is dirty.
+
+=cut
+
+sub update
+{
+ my ($self) = @_;
+ my ($vmtx) = $self->{' PARENT'}{'vmtx'};
+ my ($glyphs);
+ my ($num);
+ my ($i, $maw, $mlsb, $mrsb, $mext, $aw, $lsb, $ext);
+
+ return undef unless ($self->SUPER::update);
+ return undef unless (defined $vmtx && defined $self->{' PARENT'}{'loca'});
+ $vmtx->read->update;
+ $self->{' PARENT'}{'loca'}->read->update;
+ $glyphs = $self->{' PARENT'}{'loca'}{'glyphs'};
+ $num = $self->{' PARENT'}{'maxp'}{'numGlyphs'};
+
+ for ($i = 0; $i < $num; $i++)
+ {
+ $aw = $vmtx->{'advance'}[$i];
+ $lsb = $vmtx->{'top'}[$i];
+ if (defined $glyphs->[$i])
+ { $ext = $lsb + $glyphs->[$i]->read->{'yMax'} - $glyphs->[$i]{'yMin'}; }
+ else
+ { $ext = $aw; }
+ $maw = $aw if ($aw > $maw);
+ $mlsb = $lsb if ($lsb < $mlsb or $i == 0);
+ $mrsb = $aw - $ext if ($aw - $ext < $mrsb or $i == 0);
+ $mext = $ext if ($ext > $mext);
+ }
+ $self->{'advanceHeightMax'} = $maw;
+ $self->{'minTopSideBearing'} = $mlsb;
+ $self->{'minBottomSideBearing'} = $mrsb;
+ $self->{'yMaxExtent'} = $mext;
+ $self->{'numberOfVMetrics'} = $vmtx->numMetrics;
+ $self;
+}
+
+
+1;
+
+
+=head1 BUGS
+
+None known
+
+=head1 AUTHOR
+
+Martin Hosken Martin_Hosken@sil.org. See L<Font::TTF::Font> for copyright and
+licensing.
+
+=cut
+