Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!uunet!mcsun!inria!mirsa!daniel
From: daniel@mirsa.inria.fr (Daniel Dardailler)
Newsgroups: comp.windows.x
Subject: Re: Window sizes in X11R3
Message-ID: <486@mirsa.inria.fr>
Date: 11 Jan 90 15:10:51 GMT
References: <9001101658.AA03153@expire.lcs.mit.edu>
Organization: Bull Research Center. Sophia Antipolis. France
Lines: 17

From article <9001101658.AA03153@expire.lcs.mit.edu>, by rws@EXPO.LCS.MIT.EDU (Bob Scheifler):
> screen are "large").  Nothing really bad will happen until you overflow
> 15 bits.  There's no guarantee at this point in time that servers (even
> R4) will deal rationally with 15-bit overflow.

Why these 15 bits? 
Since window dimensions (CARD16 in the X protocol: 0+65536) are different
from window positions (INT16: -32768+32768),
my opinion is that with the viewport widget (or the Motif scrolledwindow 
as well) the toolkit tries to do a MoveWindow with an y > |32768| when the
user scrolls too far (in order to generate an Expose event for the 
application), it looks like a dimension problem but it is a positionning one.

For that matter, I have a question: 
why the Protocol (note the capital letter) does authorize 65536 pixels 
for the window dimensions if the (32768 - DisplayHeight) bottom pixels
can never be exposed ?