R help - Sep 1999 - monitor linearity

demo("graphics") notes that a circle (piechart) is a test of monitor
linearity.
With a new monitor on a new linux system with R-0.65.0 I get an ellipse. This
is not a pincushion effect and the major/minor axis ratio is constant over size
and screen location variation. Is this a hardware problem or are there
alternative possible explanations to explore?



Gordon M. Harrington		Mail:	3720 Village Place, #6308
Professor Emeritus			Waterloo, IA 50702-5848
University of Northern Iowa 	Phone:	319-291-8535
gordon.harrington at uni.edu	Fax:	319-291-8491
dryfly at aya.yale.edu			319-291-8324

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gordon.harrington at uni.edu writes:
> demo("graphics") notes that a circle (piechart) is a test of
monitor linearity.
> With a new monitor on a new linux system with R-0.65.0 I get an ellipse.
This
> is not a pincushion effect and the major/minor axis ratio is constant over
size
> and screen location variation. Is this a hardware problem or are there
> alternative possible explanations to explore?
(Actually, I always though that referred to the colour scale...) 

I get circles. Well, close enough anyway...

I suspect that your hardware is giving rectangular pixels. What's the
resolution of your display? It is possible to set up X with a non-4:3
aspect ratio (i.e. 800x600, 1024x768, 1152x864, ...) which might be
what is happening to you. Or maybe the monitor itself isn't 4:3.

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