Re: tikzpicture in margin

[Hans Hagen <j.hagen@xs4all.nl>]

On 2/14/2021 10:43 PM, Aditya Mahajan wrote:
> On Sun, 14 Feb 2021, Jigé wrote:
> 
>> Hi all.
>>
>> I'm trying to place a TikZ picture in the margin.
>> Here is a small example:
>>
>> \usemodule[tikz]
>> \setuplayout[backspace=4cm, topspace=2cm, height=middle]
>> \starttext
>> \input{lorem}
>> \margintext{I have discovered a truly
>>              marvelous proof ...  but
>>              this margin is too narrow
>>              to contain it.}
>> \input{lorem}
>> \inmargin{\externalfigure[cow] [width=\marginwidth]}
>> % The above works.
>> % The following does not:
>> \input{lorem}
>> \inmargin{
>> \starttikzpicture
>>    \draw[gray] (-2,0) grid (2,2) ;
>>    \draw plot [domain=-2:2, samples=50, smooth] (\x,{\x * \x});
>> \stoptikzpicture
>> }
>> \stoptext
>>
>> -> Undefined control sequence
> 
> Most likely because the argument of \inmargin is scanned upfront and at that time \draw etc are undefined. One option is:
> 
> \startbuffer[picture]
> \starttikzpicture
> ...
> \stoptikzpicture
> \stopbuffer
> 
> \inmargin{\getbuffer[picture]}
> 
> Another option (but better to do that in tikz module) is:
> 
> \let\draw\relax
> \let\x\relax
> 
> \inmargin{\starttikzpicture ... \stoptikzpicture}
> 
>> Actually the command \startmarginblock ... \stop... described in the ConText reference works with a TikZ picture.
> 
> Because the \start ... \stop blocks don't scan the argument.
Here's one for you to ponder:

we have this:

  % \doifelsenothing{#content}\donefalse\donetrue

we could use the slower (maybe even side effects)

  % \doifelsetext{#content}\donetrue\donefalse

but go modern instead:

    \ifparameter#content\donefalse\or\donetrue\else\donefalse\fi

i'll add that last one to lmtx

Hans

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                                           Hans Hagen | PRAGMA ADE
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