[Debian] Generate TeX formulas as SVG or PNG images Wikipédia-like

Preparation

We will use this file named texfile.tex as the .tex to convert:

\documentclass[12pt]{article}
\pagenumbering{gobble}% Remove page numbers (and reset to 1)
\begin{document}
My first \TeX~document.
$s_n = (Ta)_n = \displaystyle\sum_{k=0}^\infty T_{nk} a_k$
\end{document}

Result file

Generating PNG images

Packages you need:

• texlive (or any other TeX program, I guess)
• dvipng

Step by step

1. In the Terminal, go to the directory containing the .tex file.
2. Execute this:

   $ latex texfile.tex

   • Output:

     This is pdfTeX, Version 3.14159265-2.6-1.40.15 (TeX Live 2015/dev/Debian) (preloaded format=latex)
      restricted \write18 enabled.
     entering extended mode
     (./texfile.tex
     LaTeX2e <2014/05/01>
     Babel <3.9l> and hyphenation patterns for 2 languages loaded.
     (/usr/share/texlive/texmf-dist/tex/latex/base/article.cls
     Document Class: article 2014/09/29 v1.4h Standard LaTeX document class
     (/usr/share/texlive/texmf-dist/tex/latex/base/size12.clo)) (./texfile.aux
     ) [1] (./texfile.aux) )
     Output written on texfile.dvi (1 page, 584 bytes).
     Transcript written on texfile.log.
     

3. Convert to PNG at 150dpi (to get a larger image than default):

   $ dvipng texfile.dvi -D 150 -o texfile.png

   • Output:

     This is dvipng 1.14 Copyright 2002-2010 Jan-Ake Larsson
     [1] 

4. Remove the border white spaces of the page and add some borders using imagemagick:

   $ convert texfile.png -trim -bordercolor white -border 5x5 texfile_trimmed.png

5. Your file is ready as texfile_trimmed.png.

Script

I have made a little script to automatize the conversion, with auto-remove of intermediary files:

if latex $1
then
	BASENAME=${1%%.*}
	echo Base name is: $BASENAME
	dvipng $BASENAME.dvi -D 150 -o $BASENAME.png
	OUTPUT_FILENAME="${BASENAME}_trimmed.png"
	echo Output file name is: $OUTPUT_FILENAME
	convert $BASENAME.png -trim -bordercolor white -border 5x5 $OUTPUT_FILENAME
	if test $# = 2
	then
		if test $2 != "-keeptempfiles"
		then
			rm ${BASENAME}.{aux,dvi,log,png}
		fi
	else
		rm ${BASENAME}.{aux,dvi,log,png}
	fi
fi
exit 0

Usage

1. Save the above script as tex2png, anywhere you want, usually near your .tex files for convenience.
2. Make it executable: $ chmod +x tex2png.
3. Syntax: tex2png filename [-keeptempfiles].
   • Example: $ tex2png texfile.tex.
   • Alternatively, you can omit the .tex extension: $ tex2png texfile but I would not recommend it.
   • If you want to keep the intermediary files (dvi, log, etc.), add the -keeptempfiles argument at the end: $ tex2png texfile.tex -keeptempfiles.
4. The final image is named texfile_trimmed.png

Generating SVG images

Packages you need:

• texlive

Step by step

1. In the Terminal, go to the directory containing the .tex file.
2. Execute this:

   $ latex texfile.tex

   • Output:

     This is pdfTeX, Version 3.14159265-2.6-1.40.15 (TeX Live 2015/dev/Debian) (preloaded format=latex)
      restricted \write18 enabled.
     entering extended mode
     (./texfile.tex
     LaTeX2e <2014/05/01>
     Babel <3.9l> and hyphenation patterns for 2 languages loaded.
     (/usr/share/texlive/texmf-dist/tex/latex/base/article.cls
     Document Class: article 2014/09/29 v1.4h Standard LaTeX document class
     (/usr/share/texlive/texmf-dist/tex/latex/base/size12.clo)) (./texfile.aux
     ) [1] (./texfile.aux) )
     Output written on texfile.dvi (1 page, 584 bytes).
     Transcript written on texfile.log.
     

3. Convert to a SVG image with a 1.5 scale factor:

   $ dvisvgm texfile.dvi -TS1.5 --no-fonts

4. Your file is ready as texfile.svg.

Remarks

There is no padding in the SVG method. I have not found yet a method to add a little padding around the figure.

Also, the --no-fonts is necessary to prevent rendering issues about SVG fonts, especially with Firefox and the default SVG viewer of Debian. So the generated formula will not be selectable as a text, but at least, it will render correctly on every device with SVG support.

Background

I needed to include some nice looking formulas on my new game design wiki. I am using MediaWiki but the math add-on was not working on my server (web hosting service, not mine). So I decided to create myself the images offline and upload them as regular image files, so that I don’t need to think too much about trying to set the add-on without having all the privileges I could have on a personal server.