[R] symbols: zero radius circles are drawn.

Thomas Lumley tlumley at u.washington.edu
Tue Jun 4 02:27:40 CEST 2002

On Mon, 3 Jun 2002, Stephen Eglen wrote:

> Hi,
> I don't think this is a bug, but I thought I'd mention it in case
> others think it is not correct... I guess it is probably just a
> rounding error.
> If I use symbols() to draw some circles, any circle with radius of
> zero gets drawn as a small circle.  As an example:

It seems to be deliberate. In src/main/graphics.c:GCircle we have
    ir = radius/Rf_gpptr(dd)->ipr[0];
    ir = (ir > 0) ? ir : 1;

so that a circle of radius zero is set to a positive radius. What I don't
know is whether this is needed -- perhaps some devices won't draw
zero-radius circles correctly, for example.


Thomas Lumley			Asst. Professor, Biostatistics
tlumley at u.washington.edu	University of Washington, Seattle

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