### ======================================================
### UTIL: plot (using GD::Graph::$type)
### ======================================================
sub plot {
    
    ### Set options for graph, cf params and default
    my ($rOpt, $rData, $type, $x, $y) = @_;     # %Opt, @data, ...
    $type ||= 'hb';                             # Default horiz. bars
    $x ||= max(scalar(@{$rData->[1]})*20, 150); # Scale to num. data.pts
    $y ||= 400;                                 # Fixed (dyn: max(ceil($s/2), 400);)
     
    my @opt = %{$rOpt};                         # Flatten option hash to array
    my $graph;                                  # (width:y, height:x)
    if ($type eq 'lp') { $graph = GD::Graph::linespoints->new($y, $x); }
    if ($type eq 'hb') { $graph = GD::Graph::hbars->new($y, $x); }
    $graph->set_x_axis_font(gdTinyFont);
    $graph->set(logo            => ".\\KMD.gif",
                logo_resize     => 0.5,
                logo_position   => "LL",    );
    $graph->set(@opt) or die $graph->error;
    
    
    ### Plot graph, cf @$rData array
    my $gd = $graph->plot($rData) or die $graph->error;
    my $dir = Win32::GetCwd() . "\\plot";
    unless (-e $dir and -d $dir) { mkdir($dir) or die "can't mkdir $dir: $!"; }
    open(IMG, ">$dir\\$rOpt->{title}.png") or die "can't open $dir\\$t.png: $!";
    binmode IMG;
    print IMG $gd->png;
}