Re: Re: Animations in ConTeXt

[Mojca Miklavec <mojca.miklavec.lists@gmail.com>]

On 5/22/05, Richard Hirsch <richard.hirsch@gmx.net> wrote:
> 
> Of course you would want to put the symbol definitions and the
> definition of the fieldstack into a loop. I tried
> %% \newcount\angle
> %% \angle=0%\zerocount
> %% \dorecurse{12} {%
> %%    \number\angle:\qquad
> %%    \definestarsymbol{\the\angle}
> %%    \symbol[star \number\angle]\par
> %%    \advance\angle by 6}
> and did get the single symbols. I wasn't successful however in putting
> the symbol list of the fieldstack definition into a loop. Perhaps the
> ConTeXt gurus can help.

I discovered some possible sources of problems, but didn't manage to solve them.

I changed this part of code (just for debugging reasons):

\startuniqueMPgraphic{drawstar}{rotation}
  draw thestar rotated \MPvar{rotation};
  % this line was added
  label("\MPvar{rotation}", origin);
\stopuniqueMPgraphic

Problem N. #1:
--------------

Consider now the following definition:

\newcount\angle
\angle=0
\definesymbol
    [star \the\angle]
    [\uniqueMPgraphic{drawstar}{rotation=\the\angle}]
\advance\angle by 6
\definesymbol
    [star \the\angle]
    [\uniqueMPgraphic{drawstar}{rotation=\the\angle}]

This should define two symbols, \symbol[star 0] and \symbol[star 6].
It did, but "rotation=\the\angle" resulted in "6" in both cases (the
last value), so we get two identical pictures. \the\angle can be
replaced manually by 0/6/12/... but that's not the point.

????

Problem N. #2:
--------------

Instead of writing

\definestarsymbol{0}
\definestarsymbol{6}
\definestarsymbol{12}
...

I tried to use:

\newcount\angle
{\angle=0\loop\ifnum\angle<67%
    \definesymbol
        [star \the\angle]
        [{\uniqueMPgraphic{drawstar}{rotation=0}}]
    Defining symbol \the\angle \dots\crlf
    \advance\angle by 6
\repeat}

Because of some unknown reason \symbol[star 0], ... cannot be recalled at all.

Can anyone find the reason for problems? 

I had very similiar problems when trying to add \loop\ifnum...\repeat
to the example in http://www.fi.muni.cz/~xholecek/animations/, which
is written in plain TeX anyway.

Mojca