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Re: Bug in Graphics output of Circle primitive?

  • To: mathgroup at smc.vnet.net
  • Subject: [mg62889] Re: Bug in Graphics output of Circle primitive?
  • From: "Jean.Pellegri" <Jean.Pellegri at wanadoo.fr>
  • Date: Thu, 8 Dec 2005 00:04:15 -0500 (EST)
  • References: <dn5o7s$nih$1@smc.vnet.net>
  • Sender: owner-wri-mathgroup at wolfram.com

Bonjour

Problem scaling

In[132]:=
r = 10000;
gx = Circle[{r, 0}, r, {179Pi/180, Pi}];
Show[Graphics[{Hue[0.5],gx,PointSize[0.02],Hue[0.8],Point[{0, 0}]}], Axes -> 
False,
PlotRange -> {{-1,1}, {-1,1}}];


The graph is OK



Jean Pellegri





"Yves Klett" <yk at despammed.com> a écrit dans le message de news: 
dn5o7s$nih$1 at smc.vnet.net...
> 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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