Re: Vector Brushes for MetaFun?

[Hans Hagen via ntg-context <ntg-context@ntg.nl>]

On 9/1/2021 12:48 PM, Henning Hraban Ramm via ntg-context wrote:
> Hi, since Jacob started the pony mode, here’s one I’d like to ride:
> 
> MetaPost pens are constant, i.e. they never change over the length of a path.
> 
> Commercial vector graphics apps have “vector brushes”, e.g. Adobe Fresco:
> https://helpx.adobe.com/fresco/using/vector-brushes.html
> The page nicely shows the necessary variables.
> 
> In Inkscape you can combine “brush images” like
> https://publicdomainvectors.org/en/free-clipart/Paintbrushes-for-Inkscape/86586.html
> with pen shapes:
> https://logosbynick.com/custom-brushes-in-inkscape/
> 
> This stretches the whole shape over the path – not perfect but good enough (and the same what e.g. “my” Affinity Designer does).
> (https://affinity.serif.com/designer/)
> 
> Is this possible with MetaFun, i.e. use a closed path and distort/stretch it along an open path?
> If, how?
you can try to 'reverse engineer the result' and see what is done by 
looking at the output

anyway, i guess it some mix of existing basics, as in

\starttext

\startMPcode
     path p ; p := fullcircle scaled 4cm ;
     for i=1 upto 10 :
         nodraw p xscaled (1 randomized .1) yscaled (1 randomized .1) ;
     endfor ;
     dodraw p xscaled (1 randomized .1) yscaled (1 randomized .1)
         withtransparency (1,.5) ;
\stopMPcode

\startMPcode
     path p ; p := fullcircle scaled 4cm ;
     for i=1 upto 10 :
         draw p xscaled (1 randomized .1) yscaled (1 randomized .1)
         withtransparency (1,.5) ;
     endfor ;
     draw p xscaled (1 randomized .1) yscaled (1 randomized .1)
         withtransparency (1,.5) ;
\stopMPcode

\startMPcode
     path p ; p :=
         (         unitcircle xscaled (5cm randomized 5mm) yscaled (4cm 
randomized 3mm)) --
         (reverse (unitcircle xscaled (5cm randomized 3mm) yscaled (4cm 
randomized 5mm))) -- cycle;
     draw (p)
%         withpattern image (fill fullcircle scaled 2mm withcolor 
"darkyellow" ;)
%         withpattern image (draw figure "mill.png" ;)
         withpattern image (draw figure "hacker.jpg" ;)
         withpatternscale (1/40,1/80)
     ;

\stopMPcode

\stoptext

so, fills, eofills, patterns and such

Hans



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                                           Hans Hagen | PRAGMA ADE
               Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
        tel: 038 477 53 69 | www.pragma-ade.nl | www.pragma-pod.nl
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