Inkscape rotary encoder generator is an extension for Inkscape (http://inkscape.org/) which enables you to create
optical rotary encoder discs fast and efficiently. It currently supports creating single and two-track (quadrature) 
encoders, gray encoders and single-track gray encoders (at least for cases mentioned in NZ patent 264738).

More details in my blog http://www.dgkelectronics.com/inkscape-extension-for-creating-optical-rotary-encoder-discs

I'm currently using Python v. 2.7.3, Inkscape version 0.48.3.1 r9886.

You install the plugin by extracting the .inx and the .py file to your Inkscape extensions folder (for Linux it is 
~/.config/inkscape/extensions and for windows it is \Inkscape\share\extensions\. I have not tested this on Windows
but it *should* work.

-Kalle Hyvönen, http://www.dgkelectronics.com