Re: command for a MP graphic

[Roland Thiers <roland.thiers@gmail.com>]

≥
Le 7 mai 13 à 13:05, Wolfgang Schuster a écrit :

>
> Am 07.05.2013 um 09:51 schrieb Marco Patzer <homerow@lavabit.com>:
>
>> On 2013–05–07 Roland Thiers wrote:
>>
>>> Hi,
>>> I did this code to get a regular polygon with metafun, it works but
>>> I would like to have an user command  like  \define or \def
>>> to be able to choose the number of sides, n. I don't know how to do
>>> that ...
>>
>> Here's one way to do it:
>>
>> \startuniqueMPgraphic{polygoneregulier}{sides}
>> drawoptions (withpen pencircle scaled 2pt);
>> numeric u ; u:=1*cm ;
>> numeric n ; n:=\MPvar{sides};
>> pair a[];
>> a[0]:=(0,3u);
>> path polygone[] ;
>> for i=1 upto n :
>> a[i]:=a[0] rotatedaround(origin,i*360/n) ;
>> polygone[i]:=a[i-1]--a[i];
>> draw polygone[i]; endfor;
>> draw fullcircle scaled 6u withcolor blue;
>> \stopuniqueMPgraphic
>>
>> %% \polyreg{<number>}
>> \define[1]\polyreg
>> {\setupMPvariables[polygoneregulier][sides=#1]%%
>>  \uniqueMPgraphic{polygoneregulier}}
>
>
> \define[1]\polyreg
>  {\uniqueMPgraphic{polygoneregulier}{sides=#1}}
>
> Wolfgang
Thank you very much for this precision, Wolfgang. I tried with two  
variables and it works with this
syntax :

\startuniqueMPgraphic{polygoneregulier}
  numeric u ; u:=\MPvar{unite}*cm ;
  numeric n ; n:=\MPvar{sides};
rest of the code
\stopuniqueMPgraphic

  \define[2]\polyreg
   {\setupMPvariables[polygoneregulier][unite,sides]
\uniqueMPgraphic{polygoneregulier}{sides=#1,unite=#2}}

\starttext
%\uniqueMPgraphic{polygoneregulier}{unite=2,sides=4}
\polyreg{6}{0.5}
\stoptext

I did not find any détails on \MPvar et \setupMPvariables on the wiki,  
however
Roland


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