On Thu, 13 May 2021, Henning Hraban Ramm wrote:

> 
> > Am 11.05.2021 um 18:02 schrieb Aditya Mahajan <adityam@umich.edu>:
> > 
> > Look at this old code on how hide such code behind a macro to have a clean interface:
> > 
> > https://github.com/adityam/mp-sketch/blob/master/mp-sketch.mp
> 
> Hi Aditya,
> I’m trying to include my additions into your code, but it doesn’t work.
> 
> 
> numeric sketch_amount; sketch_amount := 3bp;
> numeric sketch_passes; sketch_passes := 5;
> 
> def sketchdraw expr p =
>   do_sketchdraw(p if (path p): randomized sketch_amount fi)
> enddef;
> 
> def do_sketchdraw(expr p) text t =
>     normaldraw p t ;
> enddef;
> 
> 
> Now I want to draw that path several times.
> 
> If I understand it right, I can’t put that into "sketchdraw" because that leaves the end open for path additions like "withcolor".
> 
> But it also doesn’t work in "do_sketchdraw"; I thought it might like this:

A slightly different approach is needed. See attached. I also added a bit a error protection in case someone sets sketch_passes to be negative by mistake. 

It may be interesting to rewrite these macros using the new key-value interface for metapost, so that something like this works:

\sketchdraw[amount=3bp, passes=5, transparency=yes] fullsquare scaled 1cm withcolor red;