TikZ and org-mode

[2017-11-25 Sat]

TikZ is a very versatile extension to LaTeX which allows you to produce nice images. Recently, whilst writing algebraic topology lecture notes, I have become a TikZ-addict and wanted to include a TikZ-generated diagram into a blog post I was writing in org-mode. After some messing around, and looking here, I figured out what to do. I wrapped my TikZ code in the following org-commands (dots added at beginning of lines and some extra spaces to stop it from compiling):

. #+HEADER: :file ../img/contour.svg :imagemagick yes . #+HEADER: :results output silent :headers '("\\usepackage{tikz}") . #+HEADER: :fit yes :imoutoptions -geometry 400 :iminoptions -density 600 . #+BEGIN_src latex . \ begin{tikzpicture} . \draw[->] (-3,0) -- (-2,0) arc[radius=0.5cm,start angle=-180,end angle=0] (-1,0) -- (1,0) arc[radius=0.5cm,start angle=180,end angle=0] (2,0) -- (3,0); . \filldraw (-1.5,0) circle[radius=1mm]; . \filldraw (1.5,0) circle[radius=1mm]; . \ end{tikzpicture} . #+END_src

When I move the cursor in org-mode onto this src-block and type C-c C-c, it runs the tikz command and generates an SVG file with my diagram in it. Now I add the line (space added to stop it from compiling)...

[ [../img/contour.svg]]

...and org-mode inserts the picture into my blog-post.

The mysterious headers achieve the following:

. #+HEADER: :file ../img/contour.svg :imagemagick yes

This tells org mode where to create the image file and how to do it (i.e. to generate PDF from Tikz and then convert it to SVG using imagemagick).

. #+HEADER: :results output silent :headers '("\\usepackage{tikz}")

This tells org mode not to include the results of running this code block into the blog post (it wrapped them in a LaTeX block which wasn't exporting to HTML).

. #+HEADER: :fit yes :imoutoptions -geometry 400 :iminoptions -density 600

This tells org mode how big and clear to make the image. Of course, ideally the SVG would be generated directly and simply from TikZ (rather than going through PDF and imagemagick), but I'm not sure how to do that. (Any suggestions?)

Comments, corrections and contributions are very welcome; please drop me an email at j.d.evans at lancaster.ac.uk if you have something to share.

CC-BY-SA 4.0 Jonny Evans.