DISLIN Examples: Web Counter

With version 10.2 of Dislin I have added a little web counter to the main site www.dislin.de. The counter is created by a small Dislin program written in Perl, which updates the counter in a file and returns the new counter as an PNG image. Here is the Perl code of the web counter:

  
#!/usr/bin/perl
use Dislin;

$file = "counter.dat";
open (FILE, $file);
$counter = <FILE>;
$counter++;
close (FILE);

open (FILE, ">$file");
print FILE $counter;
close (FILE);
 
print "Content-type: image/png\n\n";

Dislin::imgfmt ('rgb');
Dislin::scrmod ('revers');
Dislin::metafl ('virt');
Dislin::winsiz (140, 37);
Dislin::page (140, 37);
Dislin::sclmod ('full');
Dislin::disini ();
Dislin::unit   (0);
Dislin::bmpfnt ('simplx');

$iclr = Dislin::intrgb (230./255, 242./255., 242./255);
Dislin::pagfll ($iclr);

Dislin::chaspc (0.3);
$s = sprintf ("%08d", $counter);

Dislin::height (10);
$nl = Dislin::nlmess ($s);
Dislin::messag ($s, (140 - $nl)/2, 12);

$iclr = Dislin::intrgb (0.75, 0.75, 0.75);
Dislin::setclr ($iclr);
Dislin::pagera ();

$n=Dislin::rbfpng ($cbuf, 0);
Dislin::rbfpng ($cbuf, $n);
Dislin::disfin ();

print $cbuf;

The Perl script is then called from the Dislin web site as a cgi script with the IMG tag. For example: <img src="/cgi-bin/counter.pl">