transcript documentation.

This glyph is used for drawing transcripts. It is essentially a
"segments" glyph in which the connecting segments are hats. The
direction of the transcript is indicated by an arrow attached to the
end of the glyph. The following options are standard among all Glyphs. See
Bio::Graphics::Glyph for a full explanation.

  Option      Description                      Default
  ------      -----------                      -------

  -fgcolor      Foreground color	       black

  -outlinecolor	Synonym for -fgcolor

  -bgcolor      Background color               turquoise

  -fillcolor    Synonym for -bgcolor

  -linewidth    Line width                     1

  -height       Height of glyph		       10

  -font         Glyph font		       gdSmallFont

  -connector    Connector type                 0 (false)

  -connector_color
                Connector color                black

  -label        Whether to draw a label	       0 (false)

  -description  Whether to draw a description  0 (false)

  -hilite       Highlight color                undef (no color)

In addition, the alignment glyph recognizes the following
glyph-specific options:

  Option         Description                  Default
  ------         -----------                  -------

  -arrow_length  Length of the directional   8
                 arrow.

sub pad_left {

  my $self = shift;
  return 0 unless $self->{level} == 0;
  my $pad  = $self->SUPER::pad_left;
  my $strand = $self->feature->strand;
  return $pad unless defined $strand && $strand < 0;
  return $self->arrow_length > $pad ? $self->arrow_length : $pad;

}

sub pad_right {

  my $self = shift;
  return 0 unless $self->{level} == 0;
  my $pad = $self->SUPER::pad_right;
  my $strand = $self->feature->strand;
  return $pad unless defined($strand) && $strand > 0;
  return $self->arrow_length > $pad ? $self->arrow_length : $pad;

}

sub draw_connectors {

  my $self = shift;
  my $gd = shift;
  my ($left,$top) = @_;

  $self->SUPER::draw_connectors($gd,$left,$top);
  my @parts = $self->parts; # or return;

  # H'mmm.  No parts.  Must be in an intron, so draw intron
  # spanning entire range
  if (!@parts) {
    return unless $self->feature_has_subparts;
    my($x1,$y1,$x2,$y2) = $self->bounds(0,0);
    $self->_connector($gd,$left,$top,$x1,$y1,$x1,$y2,$x2,$y1,$x2,$y2);
    @parts = ($self);
  }

  # flip argument makes this confusing
  # certainly there's a simpler way to express this idea
  my $strand    = $self->feature->strand;
  my ($first,$last) = ($parts[0],$parts[-1]);

  ($first,$last) = ($last,$first) if exists $self->{flip};

  if ($strand > 0) {
    my($x1,$y1,$x2,$y2) = $last->bounds(@_);
    my $center = ($y2+$y1)/2;
    $self->{flip} ?
	$self->arrow($gd,$x1,$x1-$self->arrow_length,$center)
      :
	$self->arrow($gd,$x2,$x2+$self->arrow_length,$center);
  }

  elsif ($strand < 0) {
    my($x1,$y1,$x2,$y2) = $first->bounds(@_);
    my $center = ($y2+$y1)/2;
    $self->{flip } ?
	$self->arrow($gd,$x2,$x2+$self->arrow_length,$center)
      :
	$self->arrow($gd,$x1,$x1 - $self->arrow_length,$center);
  }

}

sub connector {

  my $self = shift;
  return $self->SUPER::connector(@_) if $self->all_callbacks;
  return ($self->option('connector') || 'hat');

}

pad_left	No description	Code
pad_right	No description	Code
draw_component	No description	Code
part_label_merge	No description	Code
draw_connectors	No description	Code
arrow_length	No description	Code
connector	No description	Code