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:
> 
>> Jeong Dal <mailto:haksan@me.com> 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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