For simple pens, you may define your own (section 9.7 of MetaPost manual).
For complicated strokes, something along these lines could be useful as a
starting point (I'm not taking cyclic paths in consideration, btw). I did
something similar with duck footprints some weeks ago:

%Sorry for the ugly code...

\starttext

\startMPpage
%Unit size

numeric u; u := 1mm;

%In a picture you are able to include everything, kinda

picture Pluma;

Pluma := image(

for i = 1 upto 5:

for j = 1 upto 5:

draw (i,j) randomized 1;

endfor

endfor

);


%Simple curve

path Camino;

Camino := origin for i = 1 upto 30: .. (u*i, u*sind (12i mod 360)) endfor;


%Strokes

for i = 0 step 1/2 until length Camino:

draw Pluma rotated (90 + angle direction i of Camino)

shifted point i of Camino;

endfor

\stopMPpage

\stoptext


Not sure if that's what you need...

Regards,


Jairo

El mar, 11 de may. de 2021 a la(s) 06:31, Mikael Sundqvist (mickep@gmail.com)
escribió:

> Hi!
>
> Not really what you ask for, perhaps, but this could be interesting
> for you: https://tex.stackexchange.com/q/39296/52406
>
> /Mikael
>
> On Tue, May 11, 2021 at 12:58 PM Henning Hraban Ramm <texml@fiee.net>
> wrote:
> >
> > Hi MetaFans,
> >
> > is it possible to get lines with Metapost that look like they were drawn
> with a pencil or brush?
> >
> > Some vector graphics apps (in my case: Affinity Designer) can use such
> naturally looking brushes for vector graphics (and I don’t know how they do
> it), but I’d like to automate/parametrize some designs, and that would
> finally be a reason to learn Metapost...
> >
> > Hraban
> >
> ___________________________________________________________________________________
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> >
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> > wiki     : http://contextgarden.net
> >
> ___________________________________________________________________________________
>
> ___________________________________________________________________________________
> 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://context.aanhet.net
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> wiki     : http://contextgarden.net
>
> ___________________________________________________________________________________
>