<%
  my ($types, $colors, $defaults) = @_;
  my %hex;

  foreach my $type (@$types) {
    my $flag = 0;

    foreach my $color (@$colors) {
      my $value = $Request->Form("$type$color");
      $flag++ unless ($value =~ /^\d+$/ and $value >= 0 and $value < 256);
    }

    if ($flag) {
      # user supplied an unacceptable value
      $hex{$type} = $defaults->{$type};
    }
    else {
      my @rgb;
      foreach my $color (@$colors) {
        push (@rgb, $Request->Form("$type$color"));
      }
      $hex{$type} = sprintf("%02X%02X%02X", @rgb);
    }
  }

  $Response->Include('form.html', $types, $colors, \%hex);
%>