Improve fontdata build tools

[pkra]

Streamline the tools so that developers can easily add support for their custom fonts (e.g., ebook readers, apps etc)

[drochgenius]

+1

I would need to add support for a custom font. Given that I have the font files at hand, not sure what are the steps required to generate the font data for MathJax.

Any hint would be greatly appreciated,

Thanks

[pkra]

It's a pretty complicated process, I'm afraid, and complexity depends on the font you're trying to add.

Right now, if you have fonts with math tables, then https://github.com/mathjax/MathJax-dev/tree/master/fonts/OpenTypeMath is probably the best place to start. You'll need to specify how to split the fonts and generate the font metric data. Then you'll have to integrate this into MathJax in a separate step.

If your font doesn't have math tables (i.e., almost all fonts), then the question is if it has the necessary characters for math at all and you'll likely have to create parts of the font data and metrics manually (since e.g. stretchy parts won't be on Unicode positions). Alternatively, you could use an already supported font to provide a fallback.

[drochgenius]

Hi Peter,

Thanks for the quick response. I will review the available options from our side first.
If I could get the math tables for the font, then I understand it would make the process easier.
We'd like to build content for young children, adapting the font to their reading skills. For example, digits would be slightly closer to handwriting.

Regards

[pkra]

It sounds unlikely that such a font will have the necessary glyphs to be used on its own -- and you probably just want roughly the ascii range from the new font; that's a use case we've encountered before.

The "right" way for this would be for us to implement a more flexible fallback chain so that you can use a "non-math" font in combination with one of the supported fonts.

We are hoping to get to the font chain early next year (as part of v3.0) and making such use cases easier is definitely a goal.