Re: shading in metapost

["Thomas A. Schmitz" <thomas.schmitz@uni-bonn.de>]

On Jan 16, 2008, at 11:22 PM, John Luciani wrote:

> There is some information on doing transparencies in
> METAPOST at http://www-math.univ-poitiers.fr/~phan/metalpha.html
>
> Using the code at the above link you should be able to produce
> the effect in your jpeg.
>
> (* jcl *)

John,

I never thanked you for your message; sorry about that! Unless I'm  
missing something, this page is just about transparency, but that  
works quite well in metafun; it was the combination of transparency  
and shading which I couldn't get right.


On Jan 24, 2008, at 1:28 AM, Mojca Miklavec wrote:
>
> In theory possible, but in practice not implemented in metafun. But  
> see
>    http://www.fauskes.net/media/pgf/pgfmanualCVS2008-01-23.pdf
> It might satisfy your needs. (Impressive!)
>
> Mojca

Thanks, Mojca, that's what I suspected. For the time being, I prefer  
metafun just because I know a little bit about it (and almost nothing  
about tikz). I have solved the problem at hand by drawing ten  
instances of a very transparent black circle on top of each other and  
increasing the scale of the pencircle slightly at every run. Which  
leads me to one last question: I wanted to be clever and do it in a  
for-loop like this:

  for i=1 upto 10:
  	pickup pencircle scaled (i*0.5) pt ;
  	draw fullcircle scaled 5mm withcolor transparent (1,0.04,black) ;
  endfor ;

Is this because the expression "pencircle scaled" expects a "numeric  
primary" as argument? And is there any way around this?

All best, and thanks to all

Thomas
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