Generating graphs with Ruby: monochrome style with SVG::Graph?

[ajalkane]

Hi,

I'm using SVG::Graph to generate some graphs that need to
be printable without colours. The default style sheet in SVG::Graph
uses colours and I couldn't at least see that it has any other
style sheet that is suitable for monochrome.

I wonder if anyone has already done such a style sheet for
SVG::Graph that I could use?