sub drawArrow {
  my ($xEnd, $yEnd, $start, $extent, $arrowLength) = @_;

   my $radians = deg2rad($start + $degrees-45);
   my $xArrow = $arrowLength * cos($radians);
   my $yArrow = $arrowLength * sin($radians);

   $can->createLine($xEnd, $yEnd, $xEnd+$xArrow, $yEnd-$yArrow);
   $can->createLine($xEnd, $yEnd, $xEnd+$yArrow, $yEnd+$xArrow);
}