Hi Fabrice,

Your code works if you add 

 setbounds currentpicture to OverlayBox ;

Indeed with this Metapost determines the boundaries of the rectangle of which you draw the left side.

Best regards: OK

On 30 Aug 2015, at 09:50, Fabrice Couvreur <fabrice1.couvreur@gmail.com> wrote:

Hi,
Hans Otared and thank you for your suggestions.
A question for Hans : why my code does not give the expected result ?
Fabrice

2015-08-29 13:35 GMT+02:00 Hans Hagen <pragma@wxs.nl>:
On 8/29/2015 1:11 PM, Otared Kavian wrote:
Hi fabrice,

I dont’t know whether this the best solution, but you can use the following definition of the MPgraphic Funny:

\startuseMPgraphic{Funny}
     interim linecap := butt ;
     path p ;
     p := unitsquare xyscaled (OverlayWidth,OverlayHeight) ;
     drawoptions (withpen pencircle scaled 6.5pt withcolor \MPcolor{MyColorA}) ;
     draw lrcorner p --urcorner p --ulcorner p withcolor white;
     draw ulcorner p --llcorner p ;

\stopuseMPgraphic

\startuseMPgraphic{Funny}
    interim linecap := butt ;
     draw leftboundary OverlayBox ;
    setbounds currentpicture to OverlayBox ;
\stopuseMPgraphic

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If your question is of interest to others as well, please add an entry to the Wiki!

maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
webpage  : http://www.pragma-ade.nl / http://tex.aanhet.net
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wiki     : http://contextgarden.net
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