#!/usr/bin/perl -w
use strict;
use GD;
use GD::Graph::lines;

my $g = new GD::Image(400,300);
plot($g);
my $a = new GD::Image(20,300);
addon($a);
my $combined = new GD::Image(420,300);
$combined->copy($g,0,0,0,0,400,300);
$combined->copy($a,400,0,0,0,20,300);
open(OUT,">combined.png") or die "Can't open output: $!\n";
binmode OUT;
print OUT $combined->png;
close OUT;

sub plot {
    my ($graphimage) = @_;
    my @data = ( 
      ["1st","2nd","3rd","4th","5th","6th","7th", "8th", "9th"],
      [    1,    2,    5,    6,    3,  1.5,    1,     3,     4]
    );
    my $graph = GD::Graph::lines->new(400, 300);
    $graph->set( 
       x_label           => 'X Label',
       y_label           => 'Y label',
       title             => 'Some simple graph',
       y_max_value       => 8,
       y_tick_number     => 8,
       y_label_skip      => 2 
    ) or die $graph->error;
    $graphimage = $graph->plot(\@data) or die $graph->error;
    open(OUT,">combined-plotpart.png") or die "Can't open output: $!\n";
    binmode OUT;
    print OUT $graphimage->png;
    close OUT;
    return;
}

sub addon {
    my ($gdadd) = @_;
    my $blue = $gdadd->colorAllocate(0,0,255);
    $gdadd->rectangle(0,0,20,300,$blue);
    return;
}