1396637 - Text shift on hover on Mozilla Gfx Team Blog with WebRender enabled

Status: VERIFIED FIXED

(Core :: Graphics: WebRender, defect, P1)

Description

[Asif Youssuff]

Attachment: jumpy on hover.gif

User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:57.0) Gecko/20100101 Firefox/57.0
Build ID: 20170904100131

Steps to reproduce:

Enable WebRender with steps:


    turn off layers.async-pan-zoom.enabled
    turn on gfx.webrender.enabled
    turn on gfx.webrendest.enabled
    turn on gfx.webrender.layers-free
    add and turn on gfx.webrender.blob-images
    if you are on Linux, turn on layers.acceleration.force-enabled

Naviagate to https://mozillagfx.wordpress.com/

Hover over links for any of:

WebRender newsletter #1
WebRender newsletter #2
WebRender newsletter #3


Actual results:

The link text jumps up and to the left, then snaps back into place with the on hover color. 


Expected results:

Text should not have jumped, color should have just changed. 

See screengrab.

Comment 1

[Aria Beingessner [:Gankra]]

On mac, blob-images and APZ-off doesn't seem to matter.

Probably my fault somehow, not sure why yet.

Comment 2

[Aria Beingessner [:Gankra]]

Ah, for some reason those have a CSS transition, which is what causes it. We're not very good at that kind of thing in webrender right now. 

Kats, any idea if we've seen this one before?

Comment 3

[Kartikaya Gupta (email:[e-mail])]

I don't recall any exising bug on file that would cover this, no.

Comment 4

[Darkspirit]

Nightly 58 x64 20171020100426 de_DE @ Debian Testing (KDE, Radeon RX480).
main profile: layers force accel + webrender + webrendest + blob-image + gpu process + omtp

WFM

(In reply to Asif Youssuff from comment #0)
Can you confirm this?

Comment 5

[Asif Youssuff]

Attachment: moving-text.mp4

It is a lot better now, it jumps a lot less. It's more of a small shift. This doesn't occur in a fresh nightly profile, however, so it continues to be unexpected. 

Updated video attached.

Comment 6

[Lee Salzman [:lsalzman]]

Attachment: disable WR subpixel positioning with FreeType

We are hitting essentially the same problem we are with Skia - that subpixel positioning is causing us to not rasterize glyphs where Cairo metrics are putting them.

So we need the same workaround for now, just to disable subpixel positioning here until such time as we punt Cairo. This should fix the epidemic of text shifting bugs we are seeing.

Comment 7

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/mozilla-inbound/rev/94d10cf318b8
disable WR subpixel positioning with FreeType. r=jrmuizel

Comment 8

[Tiberius Oros[:tiberius_oros]]

https://hg.mozilla.org/mozilla-central/rev/94d10cf318b8

Comment 9

[Darkspirit]

(In reply to Asif Youssuff from comment #5)
> Created attachment 8920741 [details]
> moving-text.mp4
> 
> It is a lot better now, it jumps a lot less. It's more of a small shift. This doesn't occur in a fresh nightly profile, however, so it continues to be unexpected. 

Is it fixed?

Comment 10

[Asif Youssuff]

It is now fixed.