From albrecht.gebhardt@uni-klu.ac.at  Wed Jun  7 22:06:24 2000
From: albrecht.gebhardt@uni-klu.ac.at (albrecht.gebhardt@uni-klu.ac.at)
Date: Wed, 7 Jun 2000 23:06:24 +0200 (MET DST)
Subject: [Rd] "clipping error in x11()" (PR#564)
Message-ID: <200006072106.XAA13880@pubhealth.ku.dk>


There seems to be an error in the X11 display code:

try:

plot(c(-30000,-1,0,1,30000),c(30000,1,0,1,30000),type="l")
points(c(-30000,-1,0,1,30000),c(30000,1,0,1,30000))

it gives a big "V" as expexted. Now zoom in using small xlim and ylim:

plot(c(-30000,-1,0,1,30000),c(30000,1,0,1,30000),type="l",
     xlim=c(-5,5),ylim=c(0,5))
points(c(-30000,-1,0,1,30000),c(30000,1,0,1,30000))

gives no "V" as expected but kind of a "M".

It occures not only on Digital Unix as indicated below but also on
Linux (SuSE 5.3 as well as SuSE 6.4), only the angles in the "M"-like display
are sligthly different. Compilers where: gcc 2.95.2 on Tru64 and SuSE 6.4,
egcs 2.91.57 on SuSE 5.3.

Interestingly the plots are correct with postscript().

The error does not occur with rwin 1001.


BTW: This is the error which "destroys" sometimes the output of plot.voronoi()
in my tripack package.


Albrecht

......................................................................
| Albrecht Gebhardt          Tel.: (++43 463) 2700/832               |
| Institut fuer Mathematik   Fax : (++43 463) 2700/834               |
| Universitaet Klagenfurt    mailto:albrecht.gebhardt@uni-klu.ac.at  |
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--please do not edit the information below--

Version:
 platform = alpha-dec-osf4.0
 arch = alpha
 os = osf4.0
 system = alpha, osf4.0
 status = 
 major = 1
 minor = 0.1
 year = 2000
 month = April
 day = 14
 language = R

Search Path:
 .GlobalEnv, Autoloads, package:base


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[Rd] "clipping error in x11()" (PR#564)
albrecht.gebhardt@uni-klu.ac.at