use strict;
use warnings;
use GraphViz;
use CGI;

my $q = new CGI();
print $q->header(), $q->start_html();

my $g = GraphViz->new(layout => 'dot', 
                      rankdir => 0, 
                      node => { height => '0.05', shape => 'box', URL => '\N' } );

$g->add_edge('A' => 'B');
$g->add_edge('A' => 'C');

# hier startet graphviz dot.exe
print $q->p($_) for (split /\n/, $g->as_ismap);

print $q->end_html;

use strict;
use warnings;
use GraphViz;
use CGI;

my $q = new CGI();
print $q->header(), $q->start_html();

open my $dot, ">", "tree.dot" || die $!;
print $dot qq(digraph g { graph [] A -> B; C -> B; });
close $dot;

my $cmd = "dot -Tgif tree.dot -o tree.gif";
system($cmd);

print $q->end_html;

use strict;
use warnings;
# use GraphViz;
use CGI;
use IPC::Run qw(run binary);

my $q = new CGI();
print $q->header(), $q->start_html();

my $dot = qq(digraph g { graph [] A -> B; C -> B; });
run ['dot', '-Tgif'], \$dot, '>', binary(), 'test_tree.gif';

print $q->end_html;

use strict;
use warnings;
use IPC::Run qw(run binary);

my $dot = qq(digraph g { graph [] A -> B; C -> B; });
run ['dot', '-Tgif'], \$dot, '>', binary(), 'test_tree.gif';