I don't get it. Examples (animations) on
http://www.fi.muni.cz/~xholecek/animations/ compile and work OK with
my TeX and Acrobat (Windows XP, Adobe Acrobat Professional 6.0.1).
However, the example below doesn't work on my computer.

I replaced some lines below with:

\starttext
  \placefigure [here] [fig:animation]
  {A simple \MetaFun\ animation,
  click \goto {here} [JS(Rotate_Star)] to start (or stop) or
  % this line was added as described in MetaFun manual
  click \goto {here} [JS(Walk_Field{vortex})] for next step}
  {\fieldstack [vortex]}
\stoptext 

which results in the PDF file attached.

Stepping in JS(Walk_Field{vortex}) works OK, while continuous
animation in JS(Rotate_Star) doesn't. Is this because of my (old?)
ConTeXt distribution (ver 2005.01.31, fmt 2005.5.16), because of my
(old/buggy?) Acrobat/OS or because of problems in JavaScript?

Thank you,
     Mojca

Willi Egger wrote:
> Hi Richard,
> 
> thanks for this example. I tried it and voilą!
> 
> Willi
> 
> Richard Hirsch wrote:
> > Richard Rascher-Friesenhausen asked
> >
> >>So again. Is it possible to write something like the above animation
> >
> > packages
> >
> >>in ConTeXt (as a module)?
> >
> >
> > If Acrobat can display them, ConTeXt can generate them.
> >
> > Here is a simple example.
> >
> > \setupoutput      [pdf]
> > \setupcolors      [state=start]
> > \setupinteraction [state=start]
> > \setuppapersize   [S6][S6]
> >
> > %% this is just code to get something to animate
> > \startMPinclusions
> >   picture thearrow, thestar;
> >
> >   drawarrow (origin--up) scaled 10mm
> >     withpen pencircle scaled 3pt
> >     withcolor .9 red;
> >   setbounds currentpicture to (fullcircle scaled 22mm);
> >
> >   thearrow:= currentpicture scaled 5;
> >   currentpicture:= nullpicture;
> >
> >   for angle=0 step 72 until 359:
> >     draw thearrow rotated angle;
> >   endfor
> >
> >   thestar:= currentpicture;
> >   currentpicture:= nullpicture
> > \stopMPinclusions
> >
> > \setupMPvariables [drawstar] [rotation=0]
> > \startuniqueMPgraphic{drawstar}{rotation}
> >   draw thestar rotated \MPvar{rotation};
> > \stopuniqueMPgraphic
> >
> >
> > %% now we define some symbols (the frames of the animated sequence)
> > \def\definestarsymbol#1{%
> >   \definesymbol [star #1] [\uniqueMPgraphic{drawstar}{rotation=#1}]}
> >
> > \definestarsymbol{0}
> > \definestarsymbol{6}
> > \definestarsymbol{12}
> > \definestarsymbol{18}
> > \definestarsymbol{24}
> > \definestarsymbol{30}
> > \definestarsymbol{36}
> > \definestarsymbol{42}
> > \definestarsymbol{48}
> > \definestarsymbol{54}
> > \definestarsymbol{60}
> > \definestarsymbol{66}
> >
> > %% the frames are put into a fieldstack
> > \definefieldstack [vortex]
> >   [star 0,  star 6,  star 12, star 18, star 24, star 30,
> >    star 36, star 42, star 48, star 54, star 60, star 66]
> >
> > %% and this is the JavaScrip code that displays the frames one by one
> > \startJSpreamble MyField used later
> > var current = 1;
> > var delay   = 200;              % 200 milliseconds
> > var timer;
> > var running = false;            % animation currently not running
> >
> > function Advance_Angle ( ) {
> >   this.getField("vortex:"+current).value = "Off";
> >   if (++current > 12)    % number of frames
> >     { current = 1; }    % loop through frames
> >   this.getField("vortex:"+current).value = "On";
> > }
> > \stopJSpreamble
> >
> > %% we want to control the starting and stopping of the animation
> > \startJScode Rotate_Star uses MyField
> > if (running) {
> >   try { app.clearInterval(timer); } catch(except) {};
> >   running = false;
> > }
> > else {
> >   timer = app.setInterval("Advance_Angle()",delay);
> >   running = true;
> > }
> > \stopJScode
> >
> >
> > \starttext
> >   \placefigure [here] [fig:animation]
> >   {A simple \MetaFun\ animation,
> >   click \goto {here} [JS(Rotate_Star)] to start (or stop)}
> >   {\fieldstack [vortex]}
> > \stoptext
> >
> > Best regards,
> >
> >   Richard