Calculating a value in metapost, and using it in ConTeXt

Calculating a value in metapost, and using it in ConTeXt

[Kate F]

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?

I thought perhaps I could \def inside btex..etex. Here's a minimal
example trying to illustrate the idea:

\startuniqueMPgraphic{canon}
    path p, q;

    h := \overlayheight;
    w := \overlaywidth;

    % imagine this is more complex
    p = (0, 0) -- (w, .5h);
    q = (0, h) -- (w, 0);

    draw p;
    draw q;

    z0 = p intersectionpoint q;
%   btex \def\Z{ ypart z0 } etex;

\stopuniqueMPgraphic

\defineoverlay[canon][\uniqueMPgraphic{canon}]
\setupbackgrounds[page][background=canon]

\setuplayout[topspace=0pt, header=0pt, height=22cm] % here I would use \Z
\showgrid

\starttext
    xyz
\stoptext

Thanks,

-- 
Kate
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Re: 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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___________________________________________________________________________________
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
archive  : http://foundry.supelec.fr/projects/contextrev/
wiki     : http://contextgarden.net
___________________________________________________________________________________

Re: Calculating a value in metapost, and using it in ConTeXt

[Kate F]

On 27 May 2015 at 00:18, Hans Hagen <pragma@wxs.nl> wrote:
> 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
>

Wonderful!

-- 
Kate
___________________________________________________________________________________
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
archive  : http://foundry.supelec.fr/projects/contextrev/
wiki     : http://contextgarden.net
___________________________________________________________________________________