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Re: Bug in Graphics output of Circle primitive?


Dear Mathgroup,

thank you very much for your suggestions. I will have to avoid using 
those wild scalings when dealing with arc primitives and use some 
workaround as described by your posts.

With best regards,
Yves

Yves Klett schrieb:
> Dear Mathgroup,
> 
> I stumbled upon a strange (and suspicious) graphics output when 
> displaying arcs with small angular length.
> 
> If I evaluate the following lines:
> 
> r = 10000;
> gx = Circle[{r, 0}, r, {179°, 180°}];
> Show[Graphics[{gx, Point[{0, 0}]}], Axes -> True,
>   PlotRange -> {Automatic, Automatic}, AxesOrigin -> {0, 0}];
> 
> (or the same in plain text format...)
> 
> r=10000;
> gx=Circle[{r,0},r,{179\[Degree],180\[Degree]}];
> Show[Graphics[{gx,Point[{0,0}]}],Axes\[Rule]True,
>      PlotRange\[Rule]{Automatic,Automatic},AxesOrigin\[Rule]{0,0}];
> 
> 
> I get the point as specified at the origin {0,0}. The arc though does 
> not intersect at the origin as it should IMHO, but somewhat left of it. 
>   Same thing occurs for arbitrary values of r.
> 
> There might be some precision problem of the postscript output 
> concerning the Circle primitive when very different axes scaling is 
> used, but any enlightment would be appreciated.
> 
> I am using V5.2 on windows. Any hints or tips to get rid of this faulty 
> output would be very welcome,
> 
> Yves Klett
> 


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