Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!wuarchive!bcm!shell!leo!lee
From: lee@leo (Bill Lee)
Newsgroups: comp.lang.postscript
Subject: Re: Non-orthogonal coordinates?
Message-ID: <1991May15.133539.14593@shell.shell.com>
Date: 15 May 1991 13:35:39 GMT
References: <91130.171855CXT105@psuvm.psu.edu>
Sender: usenet@shell.shell.com (USENET News System)
Organization: Shell Oil
Lines: 35

In article <91130.171855CXT105@psuvm.psu.edu> Christopher Tate <CXT105@psuvm.psu.edu> writes:
>Is it possible, in PostScript, to set up a non-orthogonal coordinate
>system (i.e. one in which the x and y axes are not oriented 90 degrees
>from each other)?
>
>-------
>Christopher Tate                   |
>                                   | "Idle lawyers tend to become politicians,
>cxt105@psuvm.psu.edu               |    so there is a certain social value
>{...}!psuvax1!psuvm.bitnet!cxt105  |          in keeping them busy."
>cxt105@psuvm.bitnet                |

Yes. Here's a little routine that does just what you suggest.

Bill Lee		lee@shell.com
Shell Oil Co.

-------------------------cut here-------------------------------------------
%* _________________________ Oblique __________________________________________
%* Procedure to modify the (normally) rectangular coordinate system of the
%* page to a non-right angle. When used, all x and y dimensions are
%* measured parallel to the new x and y axese. This results in squares
%* becoming parallelograms, circles becoming ellipses, etc. It also means that
%* moving off into the page will often run off the edge of the paper, so
%* be careful of the positining on the page.
%*
%*	angle Oblique
%*		where angle is the off-vertical of the Y axis in degrees.
%*		A positive angle is clockwise rotation of the Y axis 
%*		relative to existing axis.

/Oblique {
  /angle exch def
  [ 1 0 angle sin angle cos 0 0 ] concat
  } def