m4rc1e
commented
7 years ago I've compared the metrics against the old fonts and figured out values which should retain the old leading and not lead to clipping.
We currently have this situation:
Left: Old Right: New
old value totals: win total = 1266 typo total = 1266 hhea total = 1532
new value totals: win total = 1440 typototal = 1266 hheatotal = 1706
Proposed value totals: win total = 1440 typo total = 1266 hhea total = 1532 Enable use typo metrics flag in OS/2 table
Basically, my proposed typo and hhea values are the same as the old. We adopt the new win asc and desc. To negate the consequences of the larger spacing caused by the new win values, we enable 'use typo metrics'. By doing this, we get the following
Left: Proposed, MIddle: Old, Right:New
Here's the proposed vertical metric values
typoAscender: 750
typoDescender: -250
typoLineGap: 266
hheaAscender: 982
hheaDescender: -284
hheaLineGap: 266
winAscent: 1062
winDescent: 378
To enable Use Typo Metrics in glyphsapp:
Apologies I can't do this myself. I hope this helps you. Also use impallari/testing. The site caches fonts with the same name so to compare old and new fonts, you need to open the site again in a new tab/window.
Kind regards and have a nice weekend, Marc
DelveFonts
Hey folks,
Sorry to disturb again. Ok, you've solved the clipping but the line spacing is now too loose. Since it's a Friday, I'll take a stab at this myself I think. Give me a few hours.
There is a flag in the OS/2 table called, 'Use_Typo_Metrics'. Enabling this flag will make Window's applications use the OS/2 typo asc and typo desc values, instead of the Win Asc and Win Desc. Using this flag is crucial in solving this problem. By not enabling this flag and changing the win asc and desc to the bbox, we get this problem.
This error is especially troublesome on the Monospace fonts because Sublime, Notepad, vim etc all don't have control over line-height/leading.
Cheers, Marc