'Print the contents of the canvas to a postscript
file. Valid options: colormap, colormode, file, fontmap,
height, pageanchor, pageheight, pagewidth, pagex, pagey,
rotate, witdh, x, y.'

def postscript(self, cnf={}, **kw):

    return self.tk.call(((self._w, 'postscript') + self._options(cnf, kw)))
