Hi Jeong,

I played with your code and indeed it is very nice to use this animation feature (I never succeeded to imbed a movie in a TeX file typeset with Context…).
Thanks to Hans and Wolfgang, and you, I can now use such things in my presentations.

Just to say something which may be useful, one can also use \dostepwiserecurse as in

\startanimation[menu=yes]
\dostepwiserecurse{0}{20}{2}{\expanded{\startframe \MyGraphics{\recurselevel} \stopframe}}
\stopanimation

Best regards: OK

On 21 Jan 2016, at 23:47, Wolfgang Schuster <schuster.wolfgang@gmail.com> wrote:

21. Januar 2016 um 15:55
Thanks Hans, Wolfgang, Luigi

The new beta with Luatex 0.88 makes \fieldstacks and \startanimation work.
The following example of Wolfgang is now working well.

\def\MyGraphics#1{%
\unexpanded\def\MyGraphics#1{%
\startMPcode
path p,q;
p:=fullcircle scaled 72;
L:=length p;
N:=20;
q:=subpath (0,#1/N*L) of p;
draw q withcolor red;
fill fullcircle scaled 3 shifted point length q of q withcolor blue;
setbounds currentpicture to unitsquare shifted (-0.5,-0.5) scaled 75;
\stopMPcode}
\usemodule[animation]
\setupinteraction[state=start]

\starttext
\startanimation[menu=yes]
{\MyGraphics {5}}
{\MyGraphics {10}}
{\MyGraphics {15}}
{\MyGraphics {20}}
\stopanimation

\stoptext

One more question. Is there any convenient way to list \MyGraphics{#1}? I tried \dorecurse, but it just display figures one by one.  I also tried lua, but it stops with the error message  “unexpected symbol near ‘\'”.
\startanimation[menu=yes]
\dorecurse{20}{\expanded{\startframe \MyGraphics{\recurselevel} \stopframe}}
\stopanimation

Wolfgang
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