Drawing the Shaded Bars 

sub add_pdf_bars {
  my($pdf) = @_;

  my $row_y = $otm;
  while($row_y > $obm) {
    my $row_t = $row_y + $olh - 5;
    my $row_b = $row_y - 5;
    $pdf->shadeRect($osl, $row_t, $osr, $row_b, '#eeeeee');
    $row_y -= $olh * 2;
  }
}