The Tk `canvas` has a `postscript` method which allows one to create an
Encapsulated Postscript file describing the canvas. Unfortunately this
does not currently work for images in the canvas.
To get better postscript support, as well as a generally enhanced
canvas, get the Tk dash patch (http://home.wxs.nl/~nijtmans/dash.html)
by Jan Nijtmans (mailto:firstname.lastname@example.org).