1783779 - With Webrender, strike through disappears at certain level of scale

Status: NEW

(Core :: Graphics: WebRender, defect, P3)

Description

[jimsleon]

Attachment: Screenshot 2022-08-09 124102.png

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/104.0.0.0 Safari/537.36

Steps to reproduce:

I was debugging a styling issue on Firefox and was directed to https://bugzilla.mozilla.org/show_bug.cgi?id=1344545#c1, so I added text-decoration to the style of the element whose display is set to inline-flex. then zoom the content using browser zoom feature or using css tranform to scale the element

Actual results:

at certain zoom/scale levels, the strike-through will disappear

https://codepen.io/jimsleon/pen/vYRrVMj

Expected results:

Strike-through should not disappear.

Comment 1

[Mayank Bansal]

Regression : https://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=1130661c79c222fb1acd29b7ec5dc5202cdd0d2d&tochange=6567bdeb3c1e97a75f12fd72d92a6fb4a2cfcc91

Which contains bug 1681921 , which just enabled webrender (in software form) on my machine.
So this bug is WR specific.

Comment 2

[Mayank Bansal]

With WR forced, this is the regression range :
https://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=255b4f5888e9e9cdd40f59fec969af247859d76a&tochange=26de281d4c2171a75d4ad19b07fbd62bd7e69c69

Comment 3

[Mayank Bansal]

Attachment: Standalone Testcase.html

Comment 4

[Alice0775 White]

FYI,
Even with Nightly58 (20170923093829), I am able to reproduce this at certain zoom levels when I force webrender is enabled.

Comment 5

[jimsleon]

This not only happens to Strike Through but also Underline.
https://codepen.io/jimsleon/pen/vYRrVMj

Comment 6

[jimsleon]

Attachment: Underline and Strikethrough disappear

Comment 7

[jimsleon]

Attachment: FirefoxStrikeThrough.gif

Comment 8

[Brad Werth [:bradwerth]]

I found a different regression range by checking the appearance of the testcase at 170% zoom on macOS. When I do that, the strikethrough disppears at 170% but is visible at both 150% and 200%. The regression range I found is centered around July 17th, 2020: https://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=a35461d1fc07e6e855d064453363a46d32bb5a3d&tochange=bd7c35b7e234712f94f6dbb755ad983c1db8b07b

There's no obvious candidate bug in that list. I'll keep looking.

Comment 9

[Brad Werth [:bradwerth]]

Found a candidate. This could have been introduced when Euclid was updated in Bug 1650990. We'll discuss in triage.

Comment 10

[Alice0775 White]

(In reply to Alice0775 White from comment #4)

FYI,
Even with Nightly58 (20170923093829), I am able to reproduce this at certain zoom levels when I force webrender is enabled.

My regression window: https://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=ffe6cc09ccf38cca6f0e727837bbc6cb722d1e71&tochange=948dc86aabc97e16d51ad19ea90debab6f93a628

This seems to be introduced by Bug 1400034

Comment 11

[Brad Werth [:bradwerth]]

(In reply to Brad Werth [:bradwerth] from comment #9)

Found a candidate. This could have been introduced when Euclid was updated in Bug 1650990. We'll discuss in triage.

Nical, you've done some Euclid work. Can you assess if this is a Euclid issue?

Comment 12

[Jeff Muizelaar [:jrmuizel]]

Bug 1400034 seems a lot more likely than bug 1650990. Moving the ni to Glenn as he's looking at snapping/various wr quality stuffs

Comment 13

[jimsleon]

Any updates on this?

Comment 14

[Brandon]

Bug also impacts <del> and overline
https://codepen.io/HotDog_Water/pen/bGzgjWe

Comment 15

[Glenn Watson [:gw]]

No updates yet, but I'll add it to my assigned list, hopefully we can get to it within the next 2-3 months.