1872788 - In order to support all languages and scripts, use `normal` line height only

Status: RESOLVED FIXED

(Toolkit :: Themes, enhancement)

Description

[Jules Simplicio [:jules]]

It has been brought to the design systems team attention that our existing line height design token values can compromise certain scripts, such as Khmer, for example. Upon getting Jonathan Kew's, who specializes in fonts and scripts, feedback, we have discussed that normal is a better suited value and solution to guarantee proper line spacing in all languages.

Jkew's helpful feedback:

So to clarify what normal does: it doesn't simply map to a particular number (1.2 or anything else), what it does is to look at the first available font from the font-family list -- which may be a specific named font, or may be a CSS generic like sans-serif, in which case it will be resolved depending on the Firefox font prefs and the language/locale involved -- and then computes a line height based on the metrics found in that font. For non-Latin fonts, that can end up being quite different from typical Latin values; e.g. in writing systems that use a lot of tall or "stacked-up" characters, it'll probably be quite a bit larger.

Let's make sure we get rid of line height design tokens and rely on the normal line height default.

Comment 1

[Jules Simplicio [:jules]]

Attachment: Bug 1872788 - In order to support all languages and scripts rely on the default / `normal` r?#desktop-theme-reviewers

Depends on D197612

Comment 2

[Jules Simplicio [:jules]]

Attachment: Bug 1872788 - Improve spacing in preferences upon standardizing line height values r?#desktop-theme-reviewers,#settings-reviewers,#reusable-components-reviewers

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/4fde278ae659
In order to support all languages and scripts rely on the default / `normal` r=desktop-theme-reviewers,reusable-components-reviewers,dao,tgiles
https://hg.mozilla.org/integration/autoland/rev/a9528d76a91b
Improve spacing in preferences upon standardizing line height values r=desktop-theme-reviewers,settings-reviewers,dao,Gijs,reusable-components-reviewers,hjones

Comment 4

[Norisz Fay [:noriszfay]]

Backed out for causing mochitest failure on test_moz_button_group.html

Backout link

Push with failures

Failure log

Comment 5

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/dd78e55fe030
In order to support all languages and scripts rely on the default / `normal` r=desktop-theme-reviewers,reusable-components-reviewers,dao,tgiles
https://hg.mozilla.org/integration/autoland/rev/5085991b354e
Improve spacing in preferences upon standardizing line height values r=desktop-theme-reviewers,settings-reviewers,dao,Gijs,reusable-components-reviewers,hjones

Comment 6

[Noemi Erli[:noemi_erli]]

https://hg.mozilla.org/mozilla-central/rev/dd78e55fe030
https://hg.mozilla.org/mozilla-central/rev/5085991b354e