1739117 - Letter spacing is sometimes slightly too much

Status: NEW

(Core :: Layout: Text and Fonts, defect)

Description

[Calixte Denizet (:calixte)]

Attachment: Screenshot 2021-11-03 142048.png

I'm using firefox nightly 20211102213508.
Have a look on the screenshot, I underlined in red the spaces which are too large (from my point view of course).
From the devtools, if I unchecked html, body { letter-spacing: 0.01em then it looks correct.
if check/uncheck the letter-spacing property I've the impress that some letters don't get an extra spacing.

Comment 1

[Jonathan Kew [:jfkthame]]

I suspect this is caused by glyph positions being rounded to integer pixels during textrun creation, which happens before letter-spacing has been applied. (I think we have similar examples already on file...)

Comment 2

[Hiroyuki Ikezoe (:hiro)]

I can't find the bug, though there are a couple of bugs with a negative later-spacing value.