Re: Making metafun pictures fainter (shading, uncolored clash)

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

On 10/11/2021 6:30 AM, Gavin via ntg-context wrote:
> Hi List,
> 
> I made good progress producing fainter pictures in metafun. Here is a uniformly accelerated cow in the style of my book.
> 
> 
> 
> 
> I abandoned transparency, since I actually don’t want to see through anything. I am using uncolored to get the fade. It works great with a picture that is made with fill and draw, but it doesn’t work with shading. The example below has a flat disk and a round ball. The disk looks fine, but the shaded ball is not surviving the application of inverted / uncolored.
> 
> 
> \startMPinclusions
>    picture disk, ball;
>    disk := image(
>      fill fullcircle scaled 1cm withcolor .4white;
>      draw fullcircle scaled 1cm withpen pencircle scaled 0.8pt ;);
>    ball := image(
>      fill fullcircle scaled 1cm
>        withshademethod "circular"
>        withshadecenter (.25,.25)
>        withshadecolors (.8white, black);
>      draw fullcircle scaled 1cm withpen pencircle scaled 0.8pt ;);
> \stopMPinclusions
> 
> \startMPpage
>     draw inverted (disk uncolored .1white) ;
>     draw inverted (disk uncolored .2white) shifted (0.25cm,0) ;
>     draw inverted (disk uncolored .5white) shifted (1cm,0) ;
>     draw disk shifted (2.25cm,0) ;
> 
>     draw inverted (ball uncolored .1white) shifted (0, -2cm) ;
>     draw inverted (ball uncolored .2white) shifted (0.25cm, -2cm) ;
>     draw inverted (ball uncolored .5white) shifted (1cm, -2cm) ;
>     draw ball shifted (2.25cm, -2cm) ;
> \stopMPpage
> 
> 
> 
> 
> Same result in LMTX and MkIV. (ConTeXt  ver: 2021.09.17 10:01 LMTX  fmt: 2021.9.21  int: english/english)
> 
> I’m pretty happy with this uncolored trick, and will be even happier if I can get it to work with the shadings.
> 
> Any suggestions?
\startMPpage
     fill fullcircle scaled 10cm
         shifted (3cm,0)
         withcolor white ;
     fill fullcircle scaled 10cm
         shifted (3cm,0)
         withcolor black
         withtransparency (1,.25) ;

     fill fullcircle scaled 5cm
         shifted (3cm,0)
         withcolor .25[red,white] ;
\stopMPpage


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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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