Use MathJax for LaTeX rendering

[lgeiger]

Include a slimed down version of MathJax similar to preview-inline as proposed by @mangecoeur in #99

The file size is 3 MB in total (mainly the font).

I tested it with hydrogen and it works great:

[lgeiger]

I rebased it, because the diff is to large to display ;)
The relevant changes are in this commit.

[minrk]

Should mathjax be included, and not a dependency?

[mangecoeur]

@minrk Including is better because it's easier to include only what's needed (I explored both for preview-inline). There aren't really any packages on npm or bower which would fit - any 'general purpose' package would by definition include things which aren't needed - and a full MathJax install is a beast because they support many browsers and configurations. Even the subset that jupyter/ipython use is pretty heavy. You go from a 35MB install for the full MathJax, to about 12MB for a semi-slim one like ipython use, to about 3MB when you only need to support Atom/Electron (and i suspect it could be even less with a better understanding of font requirements).

[minrk]

Gotcha. It might be worthwhile to make that a package, anyway, even within the nteract org: mathjax-electron, etc.

[mangecoeur]

I guess that could work, assuming it doesn't add too much administrative overhead. Could be a package or a git submodule.

[rgbkrk]

It might be worthwhile to make that a package, anyway, even within the nteract org: mathjax-electron, etc.

This sounds like a great idea, what do you think @lgeiger? I'd use it outside of classic transformime as well (while still in an electron context).

I guess that could work, assuming it doesn't add too much administrative overhead. Could be a package or a git submodule.

We'll find that out fairly quickly!

[lgeiger]

This sounds like a great idea!

I'm a bit busy at the moment so it may take a while, but I'll give it a try this evening.

[rgbkrk]

It can be exactly what you have in here as well, including mathjax-helper.js

[lgeiger]

OK I made a new package: mathjax-electron

[lgeiger]

I couldn't figure out how to unittest the SVG from MathJax. Is there a possibility to do this?

[mangecoeur]

I was able to do some testing in preview-inline using Atom's testing framework since that gives you access to a DOM page for testing. Basically just test that an element is rendered (i.e. exists after the call). No idea how this works in bare Electron. I think it's reasonable to assume MathJax Just Works since they have their own test suite.

[rgbkrk]

You may want to work with electron-mocha, that's what we use on nteract/nteract and a few other packages instead of JSDom. Works quite well as a drop-in replacement for mocha and it can run in the renderer process by using --renderer as one of the args.

[lgeiger]

Maybe I'll try electron-mocha in the future. But for now I agree with @mangecoeur.
I think it's reasonable to assume MathJax works, so testing for the existence of the MathJax script is enough.

[rgbkrk]

Now that the phosphor folks have fully divested from transformime, I think it's reasonable for us to go ahead with this even though it says Electron on the tin (it's more "chrome-like" than Electron I suppose).

[rgbkrk]

Will this reload MathJax every time a LaTeXTransform is done?

[lgeiger]

It should only load the first time: https://github.com/nteract/mathjax-electron/blob/master/src/mathjax-electron.js#L6

[rgbkrk]

Merging, let's keep iterating. Thank you for stellar work as always @lgeiger!

[lgeiger]

Oh I'm flattered 😄.

Should we do another minor release?

[rgbkrk]

Sounds great to me.