Confirm v metrics info is consistent

[davelab6]

Observed behaviour

There are 4 places that GF currently has information about vertical metrics:

1. https://github.com/googlefonts/gf-docs/tree/master/VerticalMetrics documentation
2. FontBakery GF Profile VM check(s)
3. https://github.com/googlefonts/gf-glyphs-scripts "Official" Google Fonts QA/Production scripts for Glyphs
   1.mf-glyphs-scripts Marc Foley's personal scripts for Glyphs. The QA > Check Font script can be useful

Over time these have drifted apart.

Expected behaviour

These must all be consistent.

[felipesanches]

We have other issues here that may (or may not) be related, but I'm referencing them here to avoid duplicates:

• Is our Vertical Metrics spec inconsistent? (Is our Vertical Metrics spec inconsistent? #2841)
• Check vertical metrics clear Vietnamese (Check vertical metrics clear Vietnamese #2029)
• Vertical Metrics change (Vertical Metrics change #1162)
• GF Docs recommends setting vertical metrics that make line heights different between Windows & Mac, according to fontVal (GF Docs recommends setting vertical metrics that make line heights different between Windows & Mac, according to fontVal #2148)
• Clarify rationale and log messages: check/041: WARN: Checking Vertical Metric Linegaps. (Clarify rationale and log messages: check/041: WARN: Checking Vertical Metric Linegaps. #2164)

[m4rc1e]

Thanks Felipe. I'll see if I can tackle all of them in one go. This week I'm focusing on font names, fvar instancers and STAT etc. I'll try and get to this within the next two weeks.

[felipesanches]

thanks, @m4rc1e. May I reassign this one to you?

[m4rc1e]

SGTM. I may need your help on this as well since there's quite a lot to do. Fancy a hangout next week? We need to run some tests before we can really do anything meaningful.

[felipesanches]

perfect! Let's schedule a call, call me in private ;-)

[RosaWagner]

Since we are talking about updating the script, I would like to mentioned that right now caps are not centered with actual vertical metrics. Maybe you already discussed this, but it could be handy to have (-)TypoDescender = TypoAscender-CapsHeight.