drawing right N-gons

[Igor Schein <igor@txc.com>]

Hi, 

I need to be able to draw right N-gons in PARI.

Here's the steps I do

1) using polroots(), obtain a vector of Nth roots of unity:
v=polroots(x^N-1)
2) Sort the list by arg():
( I wrote a simple function to do that )
3) Draw:
psplothraw(real(v),imag(v),1)

The only problem with above is that the sheet of paper is rectangular,
so the image is scaled and I don't get a right N-gon.  

So my question is how can I scale, so that I get a right N-gon?

Thanks

Igor