Copyright 2000, Anthony Cook.  All rights reserved.
This program is free software, you can redistribute it and/or
modify it under the same terms as Perl itself.


What is it?
===========

Imager::Graph is intended to produce good looking graphs with a
minimum effort on the part of the user.  Hopefully I've managed that.

Currently only the pie graph class, Imager::Graph::Pie, is provided.


Imager
======

Imager::Graph can push the limits of the capabilities that Imager
provides, the default "style" will work with Imager 0.38, but the
other default styles require current CVS or Imager 0.39 when it is
released.  Note that current CVS includes bug fixes that may have an
effect on the appearance of the final output.

Once you have Imager installed, and an appropriate font, Imager::Graph
should just work, there are no other dependencies.


Fonts
=====

For best results you will need one or more attractive fonts, and one
of the outline font libraries that Imager supports.  The ImUgly font
is supplied with Imager::Graph, but it is fairly ugly, so probably
isn't useful if you want nice output.


Installation
============

Imager::Graph follows the normal perl module installation process:

   perl Makefile.PL
   make
   make test
   make install

Please Note: don't be too suprised if you get test failures,
unfortunately minor changes in the image can result in large changes
in the measure I use to check the results.  If you get test failures
please check the results in testout/

The tests require PNG file format and TrueType font format support.

Creating Graphs
===============

The aim is to make things as simple as possible, if you have some data
you can create a pie chart with:

  use Imager::Graph::Pie;

  my $font = Imager::Font->new(file=>$fontfile)
    or die "Cannot create font: ",Imager->errstr;
  my $pie_graph = Imager::Graph::Pie->new();
  my $img = $pie_graph->draw(data=>\@data);

If you want to add a legend, you need to provide some descriptive text
as well:

  my $img = $pie_graph->draw(data=>\@data, labels=>\@labels, font=>$font,
                             features=>'legend');

You might want to add a title instead:

  my $img = $pie_graph->draw(data=>\@data, font=>$font, title=>'MyGraph');

or instead of a legend, use callouts to annotate each segment:

  my $img = $pie_graph->draw(data=>\@data, labels=>\@labels,
	                     features=>'allcallouts', font=>$font);

(The following graphs use features introduce after Imager 0.38.)

If you want draw a monochrome pie graph, using hatched fills, specify
the 'mono' style:

  my $img = $pie_graph->draw(data=>\@data, style=>'mono');

The 'mono' style produces a 1 channel image by default, so if you want
to add some color you need to reset the number of channels, for
example, you could change the drawing color to red:

  my $img = $pie_graph->draw(data=>\@data, style=>'mono', 
                             fg=>'FF0000', channels=>3);


If you're feeling particularly adventurous, you could create a graph
with a transparent background, suitable for compositing onto another
image:

  my $img = $pie_graph->draw(data=>\@data, style=>'mono', 
                             bg=>'00000000', channels=>4);

If you only want the background of the graph to be transparent, while leaving other parts of the chart opaque, use the back option:

  my $img = $pie_graph->draw(data=>\@data, style=>'mono', 
                             back=>'00000000', channels=>4);

or you could make the background an image based fill:

  my $img = $pie_graph->draw(data=>\@data, style=>'mono', channels=>4,
                             back=>{ image=>$otherimage } );

If you want a "prettier" image, you could use one of the fountain fill
based styles:

  my $img = $pie_graph->draw(data=>\@data, style=>'fount_lin');

The image you receive from Imager::Graph is a normal Imager image,
typically an 8-bit/sample direct color image, though options to extend
that may be introduced in the future.


Portability
===========

Imager::Graph should work on any system that Imager works on.


More Information
================

If you have queries about Imager::Graph, please email me at
tony@develop-help.com.

A PPM compatible version of this module should be available from
http://ppd.develop-help.com/.

Thanks go to Addi for Imager.