tkinter canvas postscript and odd-even filling problem

[gabor papp]

i try to use postscript method of a canvas to
save a complex polygon in postscript format
and the result is different that it can be seen
on the canvas. 

the polygon crosses itself like a ribbon which
meets some of its parts. tkinter fills everything
of the shape, but postscript uses old-even type
filling, the parts where the polygon crosses
itself are transparent.

i tried piddle module, which works in the same way.

are there any modules which can handle this problem?
or utilities which can convert this postscipt file
to an other fileformat with same output as tkinter
canvas had?
or is it a problem with tk postscript saving?

thank you in advance,
gabor papp