I have been trying to make some graphs using GD::Graph::lines. I have run into a snag when trying to use multiple Y axes. I can configure the 1st axis with no problem at all. My problem is configuring the ticks for the second axis.

I have tried using attributes like y1_tick_number, y2_tick_number, etc. but get the error No attribute 'y2_tick_number'

I have tried specifying an array such as y_tick_number  => [3,30] but the second element seems to get ignored.

I have searched the documentation and the web but can't seem to find an answer. The idea is to provide a different set of ticks for the second data set. I would like to have 15 ticks numbered 10, 20, 30, etc. on the right side of the graph. Any help will be greatly appreciated.

Here is a short example of my test code: 
#!/usr/bin/perl

use strict;
use GD::Graph::lines;

my @data = (
    ["Mar","Apr","May","Jun","Jul"],
    [5,2,10,6,4],
    [100,80,50,60,20]
  );

my $graph = GD::Graph::lines->new(800, 600);

 $graph->set(
      title             => 'Test Graph',
      two_axes          => 'true',
      use_axis          => [1,2],
      x_label           => 'Month',
      y1_label           => 'Units',
      y1_max_value       => 15,
      y1_min_value     => 0,
      y_tick_number     => [15,15], #second element get ignored
      y_label_skip      => 0,
      y2_label           => 'Profit',
      y2_max_value       => 150,
      y2_min_value     => 0,
      #y2_tick_number     => 15, #throws error
      #y2_label_skip      => 0 #throws error
  ) or die $graph->error;

my $gd = $graph->plot(\@data) or die $graph->error;

open(IMG, '>/var/www/html/file.gif') or die $!;
  binmode IMG;
  print IMG $gd->gif;
  close IMG;

exit;

[download]
Chris Rogers

In reply to GD::Graph and Multiple Y Axes by ChrisR

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