Preflight hinting

[m4rc1e]

It would be nice to have vttLib preflight to check whether hinting will compile for a given font. I'd expect the output to show incompatible glyphs and also glyphs which use SOFTOFFSET.

Such a tool would allow me to produce a list of problematic glyphs I can send to a hinter to get fixed.

Happy to submit a pr if you think it's useful.

[m4rc1e]

Another approach is to just log all the glyphs which cannot be compiled when running vttLib compile. Atm, vtt compile will raise an error and terminate on the first glyph it cannot compile.

[madig]

PR welcome :)

[m4rc1e]

Ended up writing a gftools script for this task, https://github.com/googlefonts/gftools/blob/main/bin/gftools-check-vtt-compile.py

Can improve and transfer it to this repo but I may be a bit slow due to other tasks.

[m4rc1e]

Also looks like it was written in an ad hoc/dirty manner so it should be improved.

[madig]

Take your time :)