Math is now 404

[Artoria2e5]

When trying to figure out #699 I discovered that math is now 404:

Maybe using an external service to render the TeX wasn't such a good idea after all... What are the chances we can use KaTeX HTML/CSS output for this?

Implementation sketch

• Link to katex.min.css to output if formula exists. Now linking to an external CSS is really silly for an e-mail, but https://cdn.jsdelivr.net/npm/[email protected]/dist/katex.min.css makes extensive references to fonts and other assets, and we are never getting them all.
• For each formula block, call katex.renderToString() on it and paste in the resulting HTML. If the block is not inline, add { displayMode: true }.

Other ideas

Run mathjax and paste the SVG in -- possibly cheaper than getting the CSS, now that I think about it! Run MathJax.tex2svg() on the string, be sure to respect the inline-ness and set { display: false } if the block is inline.

[adam-p]

Nominally fixed with #261.

For client-side rendering, see #874 (and #261 and #144).