LaTeX vs. Unicode

I'm using matplotlib to create figures for my publications. For axes labels, legends, and everything else requiring text and symbols in a figure, I've so far used the excellent LaTeX support of matplotlib, and the results are (obviously) highly satisfactory:

There's a disadvantage, though: there are not too many fonts to chose from. Naively, I thought that this limitation would be lifted if I wouldn't use LaTeX, but Unicode instead:

And wouldn't XeLaTeX even combine the advantages of both?

As you can see, matplotlib allows you to use any of these options, but what you don't see is that the desired results can be achieved only with a very limited set of fonts. For example, there are only a few fonts that include the unicode character for a 'superscript minus' (for an overview, see here). Sadly, most of these are part of the ClearType Font Collection, which was introduced by Microsoft with Windows Vista. Free fonts with a 'superscript minus' include Dejavu Sans, Free Sans, and Free Serif. If the 'superscript minus' is included instead as a command by employing the internal LaTeX support of matplotlib, many more fonts become accessible. Examples are shown in the table below. But even then one can't make any assumptions: while Source Sans Pro works fine, Source Serif Pro doesn't. I have no idea why.

You see from my last statement that this post in not in the least authoritative. I'm just toddling around, and if you find a better way, I'd appreciate corrections and additions. That's particularly true for the case of XeLaTeX, the use of which seems to require OTF-only fonts with math table support. I wasn't even able to find a single Sans Serif font with this profile 😞 . Others have similar problems.

Finally, here's an archive containing the three scripts I've used to create the figures above. In each case, I let matplotlib render a pdf, convert that into an svg by pdftocairo, and compress this svg files by gzip:

./plot_uc.py
pdftocairo -svg plot_uc.pdf plot_uc.svg
gzip -S z plot_uc.svg

The results are compressed scalable vector graphics that are fully compatible with inkscape if a post-processing should be necessary. That's how I got the unicode logo in, by the way. 😉