Writing non-Latin (e.g. Chinese) text without a configured font leads to unpredictable font fallback

[LaurenzV]

Description

Example:

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Result:

Note how there are a few characters that are bolder than the rest. This is kind of a web app issue, but I'm still posting it here so I can label with with "urgent", because I think that should definitely be fixed before the next release, as it's a bad user experience. Maybe by changing the default web app fonts so that a font is chosen that supports both, Japanese and Chinese characters.

From what I can tell, the issue is that it uses MoeSong UN by default, which apparently is missing some characters, which are taken from Noto Sans CJK. Maybe we should just always use Noto Sans CJK?

Reproduction URL

No response

Operating system

No response

Typst version

• I am using the latest version of Typst

[LaurenzV]

I guess this was introduced by typst/webapp-issues#380.

[peng1999]

Maybe we should just always use Noto Sans CJK?

Maybe just move Noto Sans CJK to the higher position of fallback list.

[laurmaedje]

Maybe just move Noto Sans CJK to the higher position of fallback list.

There isn't really one. It goes into last resort fallback here, where all bets are kinda off.

[laurmaedje]

I'm not sure whether it's helpful to make it slightly less bad. Relying on font fallback will always be worse than having properly configured fonts.

I think there's things we can do (like a better default font list when lang == zh or similar), and better warnings in the web app for users that do not configure the language. But just changing the fallback order feels like a band-aid fix to me.

[LaurenzV]

Fair enough. I guess we can transfer this to webapp-issues then?

[laurmaedje]

Not sure. The web app has little say in font selection. It just provides a FontBook. So this might require changes in Typst.

[Andrew15-5]

I agree that a better fallback font selection can be used when specifying text.lang/text.region.