+++ /dev/null
-package Font::TTF::GPOS;
-
-=head1 NAME
-
-Font::TTF::GPOS - Support for Opentype GPOS tables in conjunction with TTOpen
-
-=head1 DESCRIPTION
-
-The GPOS table is one of the most complicated tables in the TTF spec and the
-corresponding data structure abstraction is also not trivial. While much of the
-structure of a GPOS is shared with a GSUB table via the L<Font::TTF::Ttopen>
-
-=head1 INSTANCE VARIABLES
-
-Here we describe the additions and lookup specific information for GPOS tables.
-Unfortunately there is no one abstraction which seems to work comfortable for
-all GPOS tables, so we will also examine how the variables are used for different
-lookup types.
-
-The following are the values allowed in the ACTION_TYPE and MATCH_TYPE variables:
-
-=over 4
-
-=item ACTION_TYPE
-
-This can take any of the following values
-
-=over 8
-
-=item a
-
-The ACTION is an array of anchor tables
-
-=item o
-
-Offset. There is no RULE array. The ADJUST variable contains a value record (see
-later in this description)
-
-=item v
-
-The ACTION is a value record.
-
-=item p
-
-Pair adjustment. The ACTION contains an array of two value records for the matched
-two glyphs.
-
-=item e
-
-Exit and Entry records. The ACTION contains an array of two anchors corresponding
-to the exit and entry anchors for the glyph.
-
-=item l
-
-Indicates a lookup based contextual rule as per the GSUB table.
-
-=back
-
-=item MATCH_TYPE
-
-This can take any of the following values
-
-=over 8
-
-=item g
-
-A glyph array
-
-=item c
-
-An array of class values
-
-=item o
-
-An array of coverage tables
-
-=back
-
-=back
-
-The following variables are added for Attachment Positioning Subtables:
-
-=over 4
-
-=item MATCH
-
-This contains an array of glyphs to match against for all RULES. It is much like
-having the same MATCH string in all RULES. In the cases it is used so far, it only
-ever contains one element.
-
-=item MARKS
-
-This contains a Mark array consisting of each element being a subarray of two
-elements:
-
-=over 8
-
-=item CLASS
-
-The class that this mark uses on its base
-
-=item ANCHOR
-
-The anchor with which to attach this mark glyph
-
-=back
-
-The base table for mark to base, ligature or mark attachment positioning is
-structured with the ACTION containing an array of anchors corresponding to each
-attachment class. For ligatures, there is more than one RULE in the RULE array
-corresponding to each glyph in the coverage table.
-
-=back
-
-Other variables which are provided for informational purposes are:
-
-=over 4
-
-=item VFMT
-
-Value format for the adjustment of the glyph matched by the coverage table.
-
-=item VFMT2
-
-Value format used in pair adjustment for the second glyph in the pair
-
-=back
-
-=head2 Value Records
-
-There is a subtype used in GPOS tables called a value record. It is used to adjust
-the position of a glyph from its default position. The value record is variable
-length with a bitfield at the beginning to indicate which of the following
-entries are included. The bitfield is not stored since it is recalculated at
-write time.
-
-=over 4
-
-=item XPlacement
-
-Horizontal adjustment for placement (not affecting other unattached glyphs)
-
-=item YPlacement
-
-Vertical adjustment for placement (not affecting other unattached glyphs)
-
-=item XAdvance
-
-Adjust the advance width glyph (used only in horizontal writing systems)
-
-=item YAdvance
-
-Adjust the vertical advance (used only in vertical writing systems)
-
-=item XPlaDevice
-
-Device table for device specific adjustment of horizontal placement
-
-=item YPlaDevice
-
-Device table for device specific adjustment of vertical placement
-
-=item XAdvDevice
-
-Device table for device specific adjustment of horizontal advance
-
-=item YAdDevice
-
-Device table for device specific adjustment of vertical advance
-
-=item XIdPlacement
-
-Horizontal placement metric id (for Multiple Master fonts - but that's all I know!)
-
-=item YIdPlacement
-
-Vertical placement metric id
-
-=item XIdAdvance
-
-Horizontal advance metric id
-
-=item YIdAdvance
-
-Vertical advance metric id
-
-=back
-
-=head1 CORRESPONDANCE TO LAYOUT TYPES
-
-Here is what is stored in the ACTION_TYPE and MATCH_TYPE for each of the known
-GPOS subtable types:
-
- 1.1 1.2 2.1 2.2 3 4 5 6 7.1 7.2 7.3 8.1 8.2 8.3
- ACTION_TYPE o v p p e a a a l l l l l l
- MATCH_TYPE g c g c o g c o
-
-
-=head1 METHODS
-
-=cut
-
-use strict;
-use Font::TTF::Ttopen;
-use Font::TTF::Delta;
-use Font::TTF::Anchor;
-use Font::TTF::Utils;
-use vars qw(@ISA);
-
-@ISA = qw(Font::TTF::Ttopen);
-
-
-=head2 read_sub
-
-Reads the subtable into the data structures
-
-=cut
-
-sub read_sub
-{
- my ($self, $fh, $main_lookup, $sindex) = @_;
- my ($type) = $main_lookup->{'TYPE'};
- my ($loc) = $fh->tell();
- my ($lookup) = $main_lookup->{'SUB'}[$sindex];
- my ($dat, $mcount, $scount, $i, $j, $count, $fmt, $fmt2, $cover, $srec, $subst);
- my ($c1, $c2, $s, $moff, $boff);
-
-
- if ($type == 8)
- {
- $fh->read($dat, 4);
- ($fmt, $cover) = TTF_Unpack('S2', $dat);
- if ($fmt < 3)
- {
- $fh->read($dat, 2);
- $count = TTF_Unpack('S', $dat);
- }
- } else
- {
- $fh->read($dat, 6);
- ($fmt, $cover, $count) = TTF_Unpack("S3", $dat);
- }
- unless ($fmt == 3 && ($type == 7 || $type == 8))
- { $lookup->{'COVERAGE'} = $self->read_cover($cover, $loc, $lookup, $fh, 1); }
-
- $lookup->{'FORMAT'} = $fmt;
- if ($type == 1 && $fmt == 1)
- {
- $lookup->{'VFMT'} = $count;
- $lookup->{'ADJUST'} = $self->read_value($count, $loc, $lookup, $fh);
- $lookup->{'ACTION_TYPE'} = 'o';
- } elsif ($type == 1 && $fmt == 2)
- {
- $lookup->{'VFMT'} = $count;
- $fh->read($dat, 2);
- $mcount = unpack('n', $dat);
- for ($i = 0; $i < $mcount; $i++)
- { push (@{$lookup->{'RULES'}}, [{'ACTION' =>
- [$self->read_value($count, $loc, $lookup, $fh)]}]); }
- $lookup->{'ACTION_TYPE'} = 'v';
- } elsif ($type == 2 && $fmt == 1)
- {
- $lookup->{'VFMT'} = $count;
- $fh->read($dat, 4);
- ($fmt2, $mcount) = unpack('n2', $dat);
- $lookup->{'VFMT2'} = $fmt2;
- $fh->read($dat, $mcount << 1);
- foreach $s (unpack('n*', $dat))
- {
- $fh->seek($loc + $s, 0);
- $fh->read($dat, 2);
- $scount = TTF_Unpack('S', $dat);
- $subst = [];
- for ($i = 0; $i < $scount; $i++)
- {
- $srec = {};
- $fh->read($dat, 2);
- $srec->{'MATCH'} = [TTF_Unpack('S', $dat)];
- $srec->{'ACTION'} = [$self->read_value($count, $loc, $lookup, $fh),
- $self->read_value($fmt2, $loc, $lookup, $fh)];
- push (@$subst, $srec);
- }
- push (@{$lookup->{'RULES'}}, $subst);
- }
- $lookup->{'ACTION_TYPE'} = 'p';
- $lookup->{'MATCH_TYPE'} = 'g';
- } elsif ($type == 2 && $fmt == 2)
- {
- $fh->read($dat, 10);
- ($lookup->{'VFMT2'}, $c1, $c2, $mcount, $scount) = TTF_Unpack('S*', $dat);
- $lookup->{'CLASS'} = $self->read_cover($c1, $loc, $lookup, $fh, 0);
- $lookup->{'MATCH'} = [$self->read_cover($c2, $loc, $lookup, $fh, 0)];
- $lookup->{'VFMT'} = $count;
- for ($i = 0; $i < $mcount; $i++)
- {
- $subst = [];
- for ($j = 0; $j < $scount; $j++)
- {
- $srec = {};
- $srec->{'ACTION'} = [$self->read_value($lookup->{'VFMT'}, $loc, $lookup, $fh),
- $self->read_value($lookup->{'VFMT2'}, $loc, $lookup, $fh)];
- push (@$subst, $srec);
- }
- push (@{$lookup->{'RULES'}}, $subst);
- }
- $lookup->{'ACTION_TYPE'} = 'p';
- $lookup->{'MATCH_TYPE'} = 'c';
- } elsif ($type == 3 && $fmt == 1)
- {
- $fh->read($dat, $count << 2);
- for ($i = 0; $i < $count; $i++)
- { push (@{$lookup->{'RULES'}}, [{'ACTION' =>
- [$self->read_anchor(TTF_Unpack('S', substr($dat, $i << 2, 2)),
- $loc, $lookup, $fh),
- $self->read_anchor(TTF_Unpack('S', substr($dat, ($i << 2) + 2, 2)),
- $loc, $lookup, $fh)]}]); }
- $lookup->{'ACTION_TYPE'} = 'e';
- } elsif ($type == 4 || $type == 5 || $type == 6)
- {
- my (@offs, $mloc, $thisloc, $ncomp, $k);
-
- $lookup->{'MATCH'} = [$lookup->{'COVERAGE'}];
- $lookup->{'COVERAGE'} = $self->read_cover($count, $loc, $lookup, $fh, 1);
- $fh->read($dat, 6);
- ($mcount, $moff, $boff) = TTF_Unpack('S*', $dat);
- $fh->seek($loc + $moff, 0);
- $fh->read($dat, 2);
- $count = TTF_Unpack('S', $dat);
- for ($i = 0; $i < $count; $i++)
- {
- $fh->read($dat, 4);
- push (@{$lookup->{'MARKS'}}, [TTF_Unpack('S', $dat),
- $self->read_anchor(TTF_Unpack('S', substr($dat, 2, 2)) + $moff,
- $loc, $lookup, $fh)]);
- }
- $fh->seek($loc + $boff, 0);
- $fh->read($dat, 2);
- $count = TTF_Unpack('S', $dat);
- $mloc = $fh->tell() - 2;
- $thisloc = $mloc;
- if ($type == 5)
- {
- $fh->read($dat, $count << 1);
- @offs = TTF_Unpack('S*', $dat);
- }
- for ($i = 0; $i < $count; $i++)
- {
- if ($type == 5)
- {
- $thisloc = $mloc + $offs[$i];
- $fh->seek($thisloc, 0);
- $fh->read($dat, 2);
- $ncomp = TTF_Unpack('S', $dat);
- } else
- { $ncomp = 1; }
- for ($j = 0; $j < $ncomp; $j++)
- {
- $subst = [];
- $fh->read($dat, $mcount << 1);
- for ($k = 0; $k < $mcount; $k++)
- { push (@$subst, $self->read_anchor(TTF_Unpack('S', substr($dat, $k << 1, 2)) + $thisloc - $loc,
- $loc, $lookup, $fh)); }
-
- push (@{$lookup->{'RULES'}[$i]}, {'ACTION' => $subst});
- }
- }
- $lookup->{'ACTION_TYPE'} = 'a';
- } elsif ($type == 7 || $type == 8)
- { $self->read_context($lookup, $fh, $type - 2, $fmt, $cover, $count, $loc); }
- $lookup;
-}
-
-
-=head2 $t->extension
-
-Returns the table type number for the extension table
-
-=cut
-
-sub extension
-{ return 9; }
-
-
-=head2 $t->out_sub
-
-Outputs the subtable to the given filehandle
-
-=cut
-
-sub out_sub
-{
- my ($self, $fh, $main_lookup, $index, $ctables, $base) = @_;
- my ($type) = $main_lookup->{'TYPE'};
- my ($lookup) = $main_lookup->{'SUB'}[$index];
- my ($fmt) = $lookup->{'FORMAT'};
- my ($out, $r, $s, $t, $i, $j, $vfmt, $vfmt2, $loc1);
- my ($num) = $#{$lookup->{'RULES'}} + 1;
- my ($mtables) = {};
- my (@reftables);
-
- if ($type == 1 && $fmt == 1)
- {
- $out = pack('n2', $fmt, Font::TTF::Ttopen::ref_cache($lookup->{'COVERAGE'}, $ctables, 2 + $base));
- $vfmt = $self->fmt_value($lookup->{'ADJUST'});
- $out .= pack('n', $vfmt) . $self->out_value($lookup->{'ADJUST'}, $vfmt, $ctables, 6 + $base);
- } elsif ($type == 1 && $fmt == 2)
- {
- $vfmt = 0;
- foreach $r (@{$lookup->{'RULES'}})
- { $vfmt |= $self->fmt_value($r->[0]{'ACTION'}[0]); }
- $out = pack('n4', $fmt, Font::TTF::Ttopen::ref_cache($lookup->{'COVERAGE'}, $ctables, 2 + $base),
- $vfmt, $#{$lookup->{'RULES'}} + 1);
- foreach $r (@{$lookup->{'RULES'}})
- { $out .= $self->out_value($r->[0]{'ACTION'}[0], $vfmt, $ctables, length($out) + $base); }
- } elsif ($type == 2 && $fmt < 3)
- {
- $vfmt = 0;
- $vfmt2 = 0;
- foreach $r (@{$lookup->{'RULES'}})
- {
- foreach $t (@$r)
- {
- $vfmt |= $self->fmt_value($t->{'ACTION'}[0]);
- $vfmt2 |= $self->fmt_value($t->{'ACTION'}[1]);
- }
- }
- if ($fmt == 1)
- {
- # start PairPosFormat1 subtable
- $out = pack('n5',
- $fmt,
- Font::TTF::Ttopen::ref_cache($lookup->{'COVERAGE'}, $ctables, 2 + $base),
- $vfmt,
- $vfmt2,
- $#{$lookup->{'RULES'}} + 1); # PairSetCount
- my $off = 0;
- $off += length($out);
- $off += 2 * ($#{$lookup->{'RULES'}} + 1); # there will be PairSetCount offsets here
- my $pairsets = '';
- my (%cache);
- foreach $r (@{$lookup->{'RULES'}}) # foreach PairSet table
- {
- # write offset to this PairSet at end of PairPosFormat1 table
- if (defined $cache{"$r"})
- { $out .= pack('n', $cache{"$r"}); }
- else
- {
- $out .= pack('n', $off);
- $cache{"$r"} = $off;
-
- # generate PairSet itself (using $off as eventual offset within PairPos subtable)
- my $pairset = pack('n', $#{$r} + 1); # PairValueCount
- foreach $t (@$r) # foreach PairValueRecord
- {
- $pairset .= pack('n', $t->{'MATCH'}[0]); # SecondGlyph - MATCH has only one entry
- $pairset .=
- $self->out_value($t->{'ACTION'}[0], $vfmt, $ctables, $off + length($pairset) + $base);
- $pairset .=
- $self->out_value($t->{'ACTION'}[1], $vfmt2, $ctables, $off + length($pairset) + $base);
- }
- $off += length($pairset);
- $pairsets .= $pairset;
- }
- }
- $out .= $pairsets;
- die "internal error: PairPos size not as calculated" if (length($out) != $off);
- } else
- {
- $out = pack('n8', $fmt, Font::TTF::Ttopen::ref_cache($lookup->{'COVERAGE'}, $ctables, 2 + $base),
- $vfmt, $vfmt2,
- Font::TTF::Ttopen::ref_cache($lookup->{'CLASS'}, $ctables, 8 + $base),
- Font::TTF::Ttopen::ref_cache($lookup->{'MATCH'}[0], $ctables, 10 + $base),
- $lookup->{'CLASS'}{'max'} + 1, $lookup->{'MATCH'}[0]{'max'} + 1);
-
- for ($i = 0; $i <= $lookup->{'CLASS'}{'max'}; $i++)
- {
- for ($j = 0; $j <= $lookup->{'MATCH'}[0]{'max'}; $j++)
- {
- $out .= $self->out_value($lookup->{'RULES'}[$i][$j]{'ACTION'}[0], $vfmt, $ctables, length($out) + $base);
- $out .= $self->out_value($lookup->{'RULES'}[$i][$j]{'ACTION'}[1], $vfmt2, $ctables, length($out) + $base);
- }
- }
- }
- } elsif ($type == 3 && $fmt == 1)
- {
- $out = pack('n3', $fmt, Font::TTF::Ttopen::ref_cache($lookup->{'COVERAGE'}, $ctables, 2 + $base),
- $#{$lookup->{'RULES'}} + 1);
- foreach $r (@{$lookup->{'RULES'}})
- {
- $out .= pack('n2', Font::TTF::Ttopen::ref_cache($r->[0]{'ACTION'}[0], $ctables, length($out) + $base),
- Font::TTF::Ttopen::ref_cache($r->[0]{'ACTION'}[1], $ctables, length($out) + 2 + $base));
- }
- } elsif ($type == 4 || $type == 5 || $type == 6)
- {
- my ($loc_off, $loc_t, $ltables);
-
- $out = pack('n7', $fmt, Font::TTF::Ttopen::ref_cache($lookup->{'MATCH'}[0], $ctables, 2 + $base),
- Font::TTF::Ttopen::ref_cache($lookup->{'COVERAGE'}, $ctables, 4 + $base),
- $#{$lookup->{'RULES'}[0][0]{'ACTION'}} + 1, 12, ($#{$lookup->{'MARKS'}} + 4) << 2,
- $#{$lookup->{'MARKS'}} + 1);
- foreach $r (@{$lookup->{'MARKS'}})
- { $out .= pack('n2', $r->[0], Font::TTF::Ttopen::ref_cache($r->[1], $mtables, length($out) + 2)); }
- push (@reftables, [$mtables, 12]);
-
- $loc_t = length($out);
- substr($out, 10, 2) = pack('n', $loc_t);
- $out .= pack('n', $#{$lookup->{'RULES'}} + 1);
- if ($type == 5)
- {
- $loc1 = length($out);
- $out .= pack('n*', (0) x ($#{$lookup->{'RULES'}} + 1));
- }
- $ltables = {};
- for ($i = 0; $i <= $#{$lookup->{'RULES'}}; $i++)
- {
- if ($type == 5)
- {
- $ltables = {};
- $loc_t = length($out);
- substr($out, $loc1 + ($i << 1), 2) = TTF_Pack('S', $loc_t - $loc1 + 2);
- }
-
- $r = $lookup->{'RULES'}[$i];
- $out .= pack('n', $#{$r} + 1) if ($type == 5);
- foreach $t (@$r)
- {
- foreach $s (@{$t->{'ACTION'}})
- { $out .= pack('n', Font::TTF::Ttopen::ref_cache($s, $ltables, length($out))); }
- }
- push (@reftables, [$ltables, $loc_t]) if ($type == 5);
- }
- push (@reftables, [$ltables, $loc_t]) unless ($type == 5);
- $out = Font::TTF::Ttopen::out_final($fh, $out, \@reftables, 1);
- } elsif ($type == 7 || $type == 8)
- { $out = $self->out_context($lookup, $fh, $type - 2, $fmt, $ctables, $out, $num, $base); }
-# push (@reftables, [$ctables, 0]);
- $out;
-}
-
-
-=head2 $t->read_value($format, $base, $lookup, $fh)
-
-Reads a value record from the current location in the file, according to the
-format given.
-
-=cut
-
-sub read_value
-{
- my ($self, $fmt, $base, $lookup, $fh) = @_;
- my ($flag) = 1;
- my ($res) = {};
- my ($s, $i, $dat);
-
- $s = 0;
- for ($i = 0; $i < 12; $i++)
- {
- $s++ if ($flag & $fmt);
- $flag <<= 1;
- }
-
- $fh->read($dat, $s << 1);
- $flag = 1; $i = 0;
- foreach $s (qw(XPlacement YPlacement XAdvance YAdvance))
- {
- $res->{$s} = TTF_Unpack('s', substr($dat, $i++ << 1, 2)) if ($fmt & $flag);
- $flag <<= 1;
- }
-
- foreach $s (qw(XPlaDevice YPlaDevice XAdvDevice YAdvDevice))
- {
- if ($fmt & $flag)
- { $res->{$s} = $self->read_delta(TTF_Unpack('S', substr($i++ << 1, 2)),
- $base, $lookup, $fh); }
- $flag <<= 1;
- }
-
- foreach $s (qw(XIdPlacement YIdPlacement XIdAdvance YIdAdvance))
- {
- $res->{$s} = TTF_Unpack('S', substr($dat, $i++ << 1, 2)) if ($fmt & $flag);
- $flag <<= 1;
- }
- $res;
-}
-
-
-=head2 $t->read_delta($offset, $base, $lookup, $fh)
-
-Reads a delta (device table) at the given offset if it hasn't already been read.
-Store the offset and item in the lookup cache ($lookup->{' CACHE'})
-
-=cut
-
-sub read_delta
-{
- my ($self, $offset, $base, $lookup, $fh) = @_;
- my ($loc) = $fh->tell();
- my ($res, $str);
-
- return undef unless $offset;
- $str = sprintf("%X", $base + $offset);
- return $lookup->{' CACHE'}{$str} if defined $lookup->{' CACHE'}{$str};
- $fh->seek($base + $offset, 0);
- $res = Font::TTF::Delta->new->read($fh);
- $fh->seek($loc, 0);
- $lookup->{' CACHE'}{$str} = $res;
- return $res;
-}
-
-
-=head2 $t->read_anchor($offset, $base, $lookup, $fh)
-
-Reads an Anchor table at the given offset if it hasn't already been read.
-
-=cut
-
-sub read_anchor
-{
- my ($self, $offset, $base, $lookup, $fh) = @_;
- my ($loc) = $fh->tell();
- my ($res, $str);
-
- return undef unless $offset;
- $str = sprintf("%X", $base + $offset);
- return $lookup->{' CACHE'}{$str} if defined $lookup->{' CACHE'}{$str};
- $fh->seek($base + $offset, 0);
- $res = Font::TTF::Anchor->new->read($fh);
- $fh->seek($loc, 0);
- $lookup->{' CACHE'}{$str} = $res;
- return $res;
-}
-
-
-=head2 $t->fmt_value
-
-Returns the value format for a given value record
-
-=cut
-
-sub fmt_value
-{
- my ($self, $value) = @_;
- my ($fmt) = 0;
- my ($n);
-
- foreach $n (reverse qw(XPlacement YPlacement XAdvance YAdvance XPlaDevice YPlaDevice
- XAdvDevice YAdvDevice XIdPlacement YIdPlacement XIdAdvance
- YIdAdvance))
- {
- $fmt <<= 1;
- $fmt |= 1 if (defined $value->{$n} && (ref $value->{$n} || $value->{$n}));
- }
- $fmt;
-}
-
-
-=head2 $t->out_value
-
-Returns the output string for the outputting of the value for a given format. Also
-updates the offset cache for any device tables referenced.
-
-=cut
-
-sub out_value
-{
- my ($self, $value, $fmt, $tables, $offset) = @_;
- my ($n, $flag, $out);
-
- $flag = 1;
- foreach $n (qw(XPlacement YPlacement XAdvance YAdvance))
- {
- $out .= pack('n', $value->{$n}) if ($flag & $fmt);
- $flag <<= 1;
- }
- foreach $n (qw(XPlaDevice YPlaDevice XAdvDevice YAdvDevice))
- {
- if ($flag & $fmt)
- {
- $out .= pack('n', Font::TTF::Ttopen::ref_cache(
- $value->{$n}, $tables, $offset + length($out)));
- }
- $flag <<= 1;
- }
- foreach $n (qw(XIdPlacement YIdPlacement XIdAdvance YIdAdvance))
- {
- $out .= pack('n', $value->{$n}) if ($flag & $fmt);
- $flag <<= 1;
- }
- $out;
-}
-
-
-=head1 AUTHOR
-
-Martin Hosken Martin_Hosken@sil.org. See L<Font::TTF::Font> for copyright and
-licensing.
-
-=cut
-
-1;
-
fnp / librarian.git / blobdiff