Path: utzoo!attcan!uunet!lll-winken!csd4.milw.wisc.edu!mailrus!purdue!decwrl!sgi!andru@rhialto.SGI.COM
From: andru@rhialto.SGI.COM (Andrew Myers)
Newsgroups: comp.sys.sgi
Subject: Re: Mouse location input.
Message-ID: <30737@sgi.SGI.COM>
Date: 14 Apr 89 20:08:56 GMT
References: <8904141229.AA24616@explorer.dgp.toronto.edu>
Sender: daemon@sgi.SGI.COM
Organization: Silicon Graphics, Inc., Mountain View, CA
Lines: 30

In article <8904141229.AA24616@explorer.dgp.toronto.edu>, juancho@dgp.toronto.edu (John Buchanan) writes:
>    Is there any way to determine the location of a mouse relative to
> a window rather than in absolute screen coordinates?  The code that I have
> now looks like this.
  [ a valid solution to the problem ]
> I cannot even imagine the thinking which led to the line drawing occuring
> in window coordinates but the mouse tracking only in screen coordinates.

    Actually, line drawing doesn't occur in window coordinates; it occurs
    in world coordinates. In a pixel-oriented paradigm, the two are the
    same; however, SGI uses a 3D paradigm, and they are quite different.

    As far as getting window-relative mouse coordinates, it seems like a
    decision fraught with trade-offs. The only real issue is programmer
    ease/confusion; as you've demonstrated, it's easy enough to translate
    screen coordinates to window coordinates.

    Personally, I prefer to get the coordinates in an absolute system,
    because it reduces confusion for me, especially when writing multi-
    window programs. De gustibus non est disputandum.

> 
> 	
> John W. Buchanan                  Dynamic Graphics Project
>                			  Computer Systems Research Institute
> 				  University of Toronto
> (416) 978-6619			  Toronto, Ontario M5S 1A4
> 

Andrew Myers