This module is an attempt to build a general purpose graphing module
that is easily modified and expanded. I borrowed most of the API from
Martien Verbruggen's GIFgraph module. I liked most of GIFgraph, but I
thought it was to difficult to modify, and it was missing a few things
that I needed, most notably legends. So I decided to write a new module
from scratch, and I've designed it from the bottom up to be easy to
modify. Like GIFgraph, Chart::* uses Lincoln Stein's GD module for all
of its graphics primitives calls.