Support non-PNG extensions

[jnothman]

matplotlib's own image_comparison "decorator defaults to generating png, pdf and svg output, but in interest of keeping the size of the library from ballooning we should only include the svg or pdf outputs if the test is explicitly exercising a feature dependent on that backend." (from here).

Only supporting PNG seems very limiting, if not counter-intuitive.

[astrofrog]

+1 to supporting other formats - my only limitation in implementing this has been time. If you have time to contribute fixes for this, that would be great!

[tacaswell]

I suspect much of the code for doing the other format -> png conversion so that these files can be compared can be directly copied from mpl.

[andrzejnovak]

Bump. Is anyone actively working on this? At least pdf?

[astrofrog]

I haven’t had a chance to work on this, and probably won’t be able to in the near future