use Imager;
my $img = Imager->new (xsize=>$width, ysize=>$height,
                       channels=>1, bits=>8);
map {
  my @polygon = ();
  map { push (@polygon,
	      [round ($_->[0] * $scale - $minx),
	       round ($maxy - $_->[1] * $scale)]) } @{$_};
  $img->polygon (points=>\@polygon, color=>'white');
} @polygons;
$img->write (fd => fileno(STDOUT), type=>'png');