Description

If an overline or underline starts or ends with a Han character, and it's adjacent to a Latin letter, then the line will extend to cover the CJK-Latin spacing, which is unwanted.

May relate to #1716.

Workaround: putting an explicit space.

#set text(font: "Noto Sans CJK SC")


- #underline[五日]M // 😓
- #underline[五日] M // ✅
- #underline[五日] // ✅

More examples

#set text(font: "Noto Sans CJK SC")

- M#underline[五日]M
- M #underline[五日] M
- 日#underline[Mn]日
- 日 #underline[Mn] 日

Analysis

Cause

Runge commented on 2025-11-26 (translated from Chinese):

This is basically because add_cjk_latin_spacing does not actually insert spacing. Instead, it adds padding to the Han characters by setting its x_advance and offset.

Desired result

Translating from Chinese in w3c/clreq#716 (comment):

The underline is by default of the same length as the character frame. When two underlines are adjacent, the length of the adjacent side is shortened to visually separate and distinguish them, while the length of the other side remains unchanged.

Additional info

Reproduction URL

No response

Operating system

Web app

Typst version

• I am using the latest version of Typst

This issue was originally reported by 差 on 2025-11-26.

Edit on 2026-12-20: #7521 has just been rejected.

…this patch (#7521) is too hacky and introduces too much maintainability burden.
What it really shows me is that the CJK-Latin spacing should not be considered part of the glyph advance in the first place, but rather be handles as a separate spacing item or similar, that's inserted.