Re: Problems with LaTeX source block

[Andreas Leha <andreas.leha@med.uni-goettingen.de>]

Hi Julien,

Julien Cubizolles <j.cubizolles@free.fr> writes:

> Hi Andreas
>
> Andreas Leha <andreas.leha@med.uni-goettingen.de> writes:
>
>> try that instead
>>
>> #+NAME: python-tikz
>> #+header: :results raw :file py2tikz_sin.png
>> #+header: :imagemagick yes :fit yes :headers '("\\usepackage{tikz,pgfplots}")
>> #+BEGIN_SRC latex :exports results
>>   \begin{tikzpicture}
>>     \node[red!50!black] (a) {A};
>>     \node (b) [right of=a] {B};
>>     \draw[->] (a) -- (b);
>>   \end{tikzpicture}
>> #+END_SRC
>
>
>
>> for problem one:  you are missing the :imagemagick yes header argument,
>> which is necessary to do the latex->png conversion.  Also, the filename
>> is inserted for you and is, thus, not part of the latex block.
>
> Thanks for clarifying it, in the worg page:
> The standard :file header argument associated with a LaTeX source code
> block by itself can take the name of either a Portable Network Graphics
> (png) or a Portable Document Format (pdf) file. File names for other
> bitmap file types can be supplied in conjunction with the :imagemagick
> header argument, described below.
> the "other bitmap file types" led me to believe that imagemagick was not
> needed for png.

Indeed, I forgot about that possibility.  I think that was introduced to
support much simpler 'formulas' -- the same way that latex snippets are
supported.  But still, it should work, I guess, with tikz code as well.

As to my understanding, if you do not explicitly specify
the :imagemagick header, internally (org-create-formula-image ) is
called which might run through dvipng -- depending on your setting of
org-latex-create-formula-image-program.  I guess, that you have set this
to dvipng.  In that case tikz is going to fail as it does not work with
'plain' latex.

But interestingly, I do not see the \usepackage{tikz} in the generated
/tmp/....tex file at all when the :imagemagick yes header argument is
missing.  So there is an issue there as well.

At this point I hope, that more knowledgeable people chime in and
clarify, whether there is some intentional limitation on latex blocks
without the :imagemagick yes header argument.


>
>> for problem two: :results raw solves that, although I agree that
>> :results file should work here.
>
> If it were to work, what would be the difference ? Would I need to add a 
> command in the LaTeX code to print the name of the file I want to link
> to ?
>

I actually expected the behaviour that we see with 'raw' to be the same
with 'file' -- without any change to the code of the latex block.

Regards,
Andreas