Closed Bug 1544830 Opened 1 year ago Closed 1 year ago

Text looks blurry when using mask-image and text-shadow


(Core :: Graphics: WebRender, defect)

68 Branch
Not set



Tracking Status
firefox-esr60 --- unaffected
firefox66 --- unaffected
firefox67 --- unaffected
firefox68 --- fixed


(Reporter: nayinain, Assigned: Gankra)


(Blocks 1 open bug, Regression)


(Keywords: regression)


(4 files)

Attached file test.html

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:68.0) Gecko/20100101 Firefox/68.0

Steps to reproduce:

1.Enable WebRender
2.Open the test.html

Actual results:

Text looks blurry.

Expected results:

Regression range:

2019-04-16T23:32:13: INFO : Narrowed inbound regression window from [4574b686, 951d2c0a] (3 builds) to [a5ccc680, 951d2c0a] (2 builds) (~1 steps left)
2019-04-16T23:32:13: DEBUG : Starting merge handling...
2019-04-16T23:32:13: DEBUG : Using url:
2019-04-16T23:32:16: DEBUG : Found commit message:
Bug 1529992 - disable the MergeClipLeaf optimization for all shadows properly. r=kats

Differential Revision:

2019-04-16T23:32:16: DEBUG : Did not find a branch, checking all integration branches
2019-04-16T23:32:16: INFO : The bisection is done.
2019-04-16T23:32:16: INFO : Stopped

Sorry for my bad English.

Keywords: regression
Regressed by: 1529992
Attached image good.png
Attached image bad.png
Assignee: nobody → a.beingessner
Ever confirmed: true
Blocks: wr-snap

This only happens if the blur is an odd number on non-hidpi. Considering we internally divide the blur in half, an odd blur would lead to a fractional size change. As such I expect this is a snapping bug. Will check if aosmond's snapping fixes also fixes this.

Can similarly reproduce on hidpi with a blur radius of 5.5px.

Attached image tabbar.png

text blurry on tab titles.

oof, showing up in the title bar probably mean I'll need to revert the change regardless of if andrew's patch will fix it (patch may not land for a while).

ni?aosmond just so we remember to check this regardless

Flags: needinfo?(aosmond)

disabled the offending code in Bug 1544895, fixing this but reintroducing the (lesser) bug it was fixing

Closed: 1 year ago
Resolution: --- → FIXED
Flags: needinfo?(aosmond)
Target Milestone: --- → mozilla68
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