Scaling inconsistency between text and glyphs

[dstoliker]

🗹 Requirements

• [x] I have searched the issues for my issue and found nothing related and/or helpful
• [x] I have searched the FAQ for help
• [x] I have searched the Wiki for help

🎯 Subject of the issue

Experienced behavior: After upgrading to the latest version of the Hack nerd font via homebrew, there is an an apparent inconsistency between text and glyph scaling. I have a command line prompt configured with Oh My Posh with powerline symbols. After upgrading my font to the latest version, the glyphs no longer line up vertically. The glyphs are now taller. See screenshots below.

Expected behavior: Text and glyphs should align as they did before the upgrade.

Example symbols: \ue0b6 \ue0b4

🔧 Your Setup

• Which font are you using (e.g. Anonymice Powerline Nerd Font Complete.ttf)?
  • Hack Regular Nerd Font Complete.ttf
• Where did you get the file from (download link, self patched, source downloaded from link...)
  • Mac cask homebrew install
• Which terminal emulator are you using (e.g. iterm2, urxvt, gnome, konsole)?
  • iterm2
• Are you using OS X, Linux or Windows? And which specific version or distribution?
  • MacOS 12.6.2 (Monterey)

★ Screenshots (Optional)

Powerline bar as it appeared before font package upgrade:

After upgrade:

iTerm2 font settings:

[Finii]

Sorry to hear that. Can see the differences...

[Finii]

Thanks for reporting. And thanks for a complete report with all the details I need to reproduce :+1:

[Finii]

[Finii]

Oh man, do I hate the metrics inconsistencies :unamused:

And whats this

[Finii]

On my machine with tilix

When I can see it, it should be 'easy' to fix.

[Finii]

I think I found the reason.

Introduced a gap-redistribution with #943 The problem is that the gap is always redistributed, even if the font is based on the old WIN metrics. That does not have a gap :roll_eyes:

Rewriting the gap stuff right now.

Thanks again for reporting!

---

Useful links

• https://glyphsapp.com/learn/vertical-metrics
• https://github.com/source-foundry/font-line

In fontforge we have (example for ascent)

sourceFont.os2_winascent
sourceFont.os2_typoascent
sourceFont.hhea_ascent
sourceFont.ascent       <=- what is represented by this

[Finii]

Systematic examination of all source fonts regarding vertical metrics, one file of each font chosen at random.

find src/unpatched-fonts -iname '*.[ot]tf' | \
  sed -E 's! !\\!g;s!([^/]*/[^/]*/[^/]*).*!\0 \1!' | \
  sort | uniq -f 1 | sed 's! .*!!;s!\\! !g;s!^!"!;s!$!"!' | \
  xargs font-line report

Font	hhea/UPM	typo/UPM	win/UPM	use typo metrics	gap	win/mac	note
3270	1.09	1.0	1.09	X	X	:red_square:	forgot to set typo-gap?
Agave	1.12	1.0	1.12	X	:red_square:
Anonymous	1	1	1	:heavy_check_mark:
Arimo	1.15	1.09	1.15	X	:heavy_check_mark:
Aurulent	1.3	1.09	1.3	X	:heavy_check_mark:
BigBlue	1	1	1	X	:heavy_check_mark:
Bitstream Vera	1.16	1.2	1.16	X	:heavy_check_mark:
Cascadia	1.16	1.16	1.32	X	:heavy_check_mark:
CodeNewRoman	1.17	1.17	1.17	X	:heavy_check_mark:
Couisine	1.13	0.842	1.13	:heavy_check_mark:
DaddyTime	1.25	1.25	1.25	X	:heavy_check_mark:
DejaVu	1.16	1.2	1,16	X	:heavy_check_mark:
Droid	1.16	1.07	1.16	X	:heavy_check_mark:
Fantasque	1.05	1.05	1.05	X	X	:heavy_check_mark:
Fira	1.23	1.23	1.23	X	:heavy_check_mark:
Fira Mono	1.4	1.4	1.4	X	:heavy_check_mark:
Gohu	1.18	1.18	1.18	X	X	:heavy_check_mark:
Go Mono	1.16	1.16	1.16	X	:heavy_check_mark:
Hack	1.16	1.2	1.16	X	:heavy_check_mark:
Hasklig	1.26	1	1.26	:heavy_check_mark:
HeavyData	1.15	1.09	1.15	X	:heavy_check_mark:
Hermit	1.56	1.09	1.56	X	X	:red_square:
iA writer	1.3	1.3	1.3	X	:heavy_check_mark:
IBM Plex	1.3	1.3	1.3	X	:heavy_check_mark:
InconsolataGo	1.05	1.05	1.05	:heavy_check_mark:
Inconsolata	1.05	1.05	1.46	X	:heavy_check_mark:
Inconsolata LGC	1.46	1	1.46	X	:heavy_check_mark:
Iosevka	1.25	1.25	1.25	X	X	:heavy_check_mark:
JetBrains Mono	1.32	1.32	1.32	X	:heavy_check_mark:
Lekton	1	1	1.7	:red_square:
Liberation	1.13	0.842	1.13	:heavy_check_mark:
Lilex	1.3	1.3	1.3	X	:heavy_check_mark:
Meslo	1.55	1.59	1.55	X	:heavy_check_mark:
Monofur	1	1	1	X	:heavy_check_mark:
Monoid	1.33	1.33	1.33	X	:heavy_check_mark:
Mononoki	1.12	1.2	1.12	X	:heavy_check_mark:
M+	1.49	1.09	1.49	X	:heavy_check_mark:
Noto	1.17	1.17	1.17	:heavy_check_mark:
OpenDyslexic	3.58	1.94	3.58	:heavy_check_mark:
Overpass	1.53	1.27	1.53	X	X	:red_square:
ProFont	1.23	1.23	1.23	:heavy_check_mark:
ProggyClean	0.812	1	0.812	:heavy_check_mark:
Roboto	1.17	1.05	1.2	X	:red_square:	'alomst ok'
ShareTech	1.13	1.13	1.13	:heavy_check_mark:
SourceCode	1.26	1	1.26	:heavy_check_mark:
SpaceMono	1.48	1.48	1.48	X	:heavy_check_mark:
Terminus	1.1	1.09	1.1	X	X	:red_square:	'almost ok'
Tinos	1.15	1.04	1.15	X	:heavy_check_mark:
Ubuntu	1.15	1.02	1.15	X	:heavy_check_mark:
Ubuntu Mono	1	0.907	1	X	:heavy_check_mark:
Victor Mono	1.41	1.41	1.41	X	X	:heavy_check_mark:

Most crucial is that WIN does use the other gaps?! See https://learn.microsoft.com/en-us/typography/opentype/spec/recom#baseline-to-baseline-distances

[Finii]

I will combine this with #1055

[Finii]

Problematic cases:

font	behavior	hhea	typo	win	ymin	ymax	y height
3270	[2]	2180	2000	2180	406	1626	2032
Agave	[2]	2304	2048	2304	512	1792	2304
Hermit	[2]	1506	1092	1506	414	1000	1414
Lekton	[1]	1000	1000	1697	585	1112	1697
Overpass	[2]	1532	1266	1532	378	1062	1440
Roboto	[3] 2.5%	2400	2150	2458	555	2163	2718
Terminus	[3] 3%	1122	1090	1122	183	845	1028

[1] Mismatch detected, chooses TYPO [2] Mismatch detected, chooses WIN [3] Mismatch detected, following USE-TYPO-METRICS

All looks ok, except Lekton, the only font that selects TYPO. So changing algo to not guess but always use WIN in thoses cases

[tjapro]

Sorry, to ask this here but I cannot find what I want ...

@dstoliker Where/What is these glyphs (the ones right in the line begining)?

[Finii]

This rounded line? At 2570:

[Finii]

While doing v3.0.0 ... Lekton is still problematic, too big gaps between lines:

Lets have a look at the table from above:

Lekton was the only font that selected TYPO but we forced it to WIN, because not all glyphs fit into the values from TYPO. But that seems to be wrong. Examining the glyphs that are really bigger than the TYPO line spaces, these are only graphical glyphs that shall span multiple lines. So I guess we should revert that change and render Lekton with the TYPO values.

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