#!/usr/bin/perl
use warnings;
use strict;
use GD::Graph::mixed;

my @data = (
    ["1st","2nd","3rd","4th","5th","6th","7th", "8th", "9th"],
    [    1,    4,    9,   16,   25,   36,   49,    64,    81],      # wants left:   0 .. 100     'x**2',
    [    1,  1.4,  1.7,    2,  2.2,  2.4,  2.6,   2.8,     3],      # wants right:  0 .. 5       '~sqrt(x)'
    [   99,   88,   77,   66,   55,   44,   33,    22,    11],      # wants left:   0 .. 100     '11*(10-x)',
    [  0.5,  1.0,  1.5,  2.0,  2.5,  3.0,  3.5,   4.0,   4.5],      # wants right:  0 .. 5       '0.5x',
    [    1,    2,    3,    4,    5,    4,    3,     2,     1],      # wants right:  0 .. 5       '123454321'
    [   98,   76,   54,   32,   10,   '',   '',    '',    ''],      # wants left:   0 .. 100     'descend',
);

my $my_graph = new GD::Graph::mixed( );
my %opts = (
        transparent => '0',
        x_label => 'nth',
        y1_label => 'big',
        y2_label => 'small',
    title => 'Using two axes',
        y1_max_value => 100,
        y2_max_value => 5,
        y_tick_number => 8,
        y_label_skip => 2,
        long_ticks => 1,
    use_axis => [1,2,1,2,2,1],      # big, small, big, small, small, big
        legend_placement => 'BR',
        x_labels_vertical => 1,
        x_label_position => 1/2,
        two_axes => 1,
    legend_marker_width => 100,

    l_margin            => 10,
    b_margin            => 10,
    r_margin            => 20,
    t_margin            => 10,
    show_values         => 1,
);
$my_graph->set(%opts);
$my_graph->set_legend( 'x**2', '~sqrt(x)', '11*(10-x)', '0.5x', '123454321', 'descend');
save_it($my_graph, \@data, 'out1.png');

# second graph, same as the first (except for use_axis)
$opts{use_axis} = [1,2,1,1,1,1];                # big, small, big, big<will shrink>, big<will shrink>
my $second_graph = new GD::Graph::mixed( );
$second_graph->set(%opts);
$second_graph->set_legend( 'x**2', '~sqrt(x)', '11*(10-x)', '0.5x', '123454321', 'descend');
save_it($second_graph, \@data, 'out2.png');

sub save_it {
    my ($graph, $data_ref, $fname) = @_;
    my $gd = $graph->plot($data_ref) or die $graph->error;

    open(my $img, '>', $fname) or die "$fname: $!\n";
    binmode $img;
    print {$img} $gd->png;
    close $img;
}