[NTG-context] Calculating a value in metapost, and using it in ConTeXt

[Hans Hagen]

On 5/26/2015 9:17 PM, Kate F wrote:
> Hello,
>
> Is it possible to calculate the position of something in Metapost, and
> to export that value to TeX such that I can use it in setups and
> things?

it depends on what you want to calculate

\startMPcalculation
     path p, q;

     h := PaperHeight;
     w := PaperWidth;

     p = (0, 0) -- (w, .5h);
     q = (0, h) -- (w, 0);

     z0 = p intersectionpoint q;

     passvariable("z",ypart z0) ;
\stopMPcalculation

\setuplayout
   [topspace=0pt,
    header=0pt,
    height=\MPrunvar{z}bp]

\showgrid

\starttext
     xyz:\MPrunvar{z}
\stoptext




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