#!/usr/bin/perl -w

use strict;
use Chart::Plot;

my $img = Chart::Plot->new();

my @xdataset = qw(791.312 809.298 825.259 842.510 855.028 861.120 
                  870.554 870.977 877.036 893.436 1060.006 1066.030 
                  1081.967 1270.989 2211.105 2225.178 2239.090);
my @ydataset = qw(1383.8 1863.9 1247   2191.4 2101.2 624.96 
                  552.55 1050.3 690.71 538.11 705.84 566.41 
                  397.68 133.13 158.5 91.587 82.42);

$img->setGraphOptions (
                       'horGraphOffset' => 75,
                       'vertGraphOffset' => 100,
                       'horAxisLabel' => 'mass/charge',
                       'vertAxisLabel' => 'intensity',
                      );

# plots nothing visible, but sets up axis scales:
$img->setData (\@xdataset, \@ydataset,  'nolines nopoints');

# now draw some vertical bars:
my $gdobj = $img->getGDobject;
my $blue = $gdobj->colorAllocate(0,0,255);
for my $i (0..$#xdataset) {
  $gdobj->line($img->data2pxl($xdataset[$i],0),
               $img->data2pxl($xdataset[$i], $ydataset[$i]),
               $blue);
}

open (WR,'>plot.png') or die ("Failed to write file: $!");
binmode WR;            # for DOSish platforms
print WR $img->draw();
close WR;