1566604 - FireFox 69 scrolling and/or font rendering issue (see screenshot)

Status: RESOLVED DUPLICATE of bug 1566712

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

Description

[User Dderss]

Attachment: FireFox 69 scrolling (and, or font rendering) issue.png

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:69.0) Gecko/20100101 Firefox/69.0

Steps to reproduce:

Just browsing.

Actual results:

From time to time FireFox shrinks text vertically, skipping a few lines, during scrolling -- exactly at the very threshold between visible and not yet visible text if the users make a pause during the scrolling. The issue stays on until the user scrolls the part completely away up or down so the corrupted part would be re-rendered, and then it looks perfectly fine.

Expected results:

Perfectly accurate text at all times.

Comment 1

[Jeff Muizelaar [:jrmuizel]]

Can you check the "Compositing" feature in about:support? Does it say "WebRender"?

Comment 2

[User Dderss]

Yes.

Comment 3

[User Dderss]

I forgot to add information that might be relevant: as you can see from the screenshot, my Windows 10 runs in graphics scaling mode (about 138% of versus 100% scale by default). This should not affect the issue of lines being skipped at the border of the "viewport" after scrolling is paused, but still.

Comment 4

[User Dderss]

Attachment: Double lines in Firefox 69 scrolling (and, or text render).png

So it looks like a couple of lines get either erased or duplicated at the border of the scrolling viewport.

Comment 5

[Jeff Muizelaar [:jrmuizel]]

I suspect this is a dup of bug 1565473

Comment 6

[Darkspirit]

Please leave a note or reopen this bug in case you see it again. I saw it on Reddit, but bug 1566712 fixed it.