Snehanshu Shah > GDGraph-histogram-1.1 > GD::Graph::histogram

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Module Version: 1.1   Source  

NAME ^

GD::Graph::histogram - Histogram plotting module for Perl5

SYNOPSIS ^

  use GD::Graph::histogram;

DESCRIPTION ^

GD::Graph::histogram extends the GD::Graph module to create histograms. The module allow creation of count or percentage histograms.

USAGE ^

Fill an array with all the data values that are to be plotted. Note that GD::Graph::histogram unlike the other GD::Graph modules can only plot one data set at a time.

        $data = [1,5,7,8,9,10,11,3,3,5,5,5,7,2,2];

Create the graph

        my $graph = new GD::Graph::histogram(400,600);

Set graph options

        $graph->set( 
                x_label         => 'X Label',
                y_label         => 'Count',
                title           => 'A Simple Count Histogram Chart',
                x_labels_vertical => 1,
                bar_spacing     => 0,
                shadow_depth    => 1,
                shadowclr       => 'dred',
                transparent     => 0,
        ) 
        or warn $graph->error;

plot the graph

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

save the graph to a file

        open(IMG, '>histogram.png') or die $!;
        binmode IMG;
        print IMG $gd->png;

METHODS ^

GD::Graph::histogram supports all the methods support by GD::Graph. Please refer to the GD::Graph documentation for more information.

The only method that behaves differently is plot

The plot method provided by GD::Graph::histogram expects a reference to an array of numbers.

Based on the input data, GD::Graph::histogram will generate the appropriate labels for the X axis. The X axis label represent the center point of the range of each histogram bin.

OPTIONS ^

GD::Graph::histogram supports all the options supported by GD::Graph::bars. Please refer to the GD::Graph documentation for more information.

The two additional options that are specific to GD::Graph::histogram are:

        histogram_bins
                Specify the number of histogram bins to bucket the data into.
                The default is for the module to automatically computed the
                histogram bins based on the data.

        histogram_type
                Can be set to either 'percentage' or 'count'. By default the module
                will create 'count' histograms.

NOTES ^

As with all Modules for Perl: Please stick to using the interface. If you try to fiddle too much with knowledge of the internals of this module, you could get burned. I may change them at any time.

AUTHOR ^

        Snehanshu Shah
        perl@whizdog.com
        http://www.whizdog.com

ACKNOWLEDGEMENTS ^

Thanks for all the feedback, bug reports and bug fixes

Martin Corley Jonathan Barber William Miller

COPYRIGHT ^

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

The full text of the license can be found in the LICENSE file included with this module.

SEE ALSO ^

perl(1), GD::Graph

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