1544830 - Text looks blurry when using mask-image and text-shadow

Status: RESOLVED FIXED

(Core :: Graphics: WebRender, defect)

Description

[nayinain]

Attachment: 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: https://hg.mozilla.org/integration/autoland/json-pushes?changeset=951d2c0a477d5b5c9c1682d7a7f3b0f9aad7ae41&full=1
2019-04-16T23:32:16: DEBUG : Found commit message:
Bug 1529992 - disable the MergeClipLeaf optimization for all shadows properly. r=kats

Differential Revision: https://phabricator.services.mozilla.com/D27114

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

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Sorry for my bad English.

Comment 1

[nayinain]

Attachment: good.png

Comment 2

[nayinain]

Attachment: bad.png

Comment 3

[Aria Beingessner [:Gankra]]

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.

Comment 4

[Aria Beingessner [:Gankra]]

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

Comment 5

[nayinain]

Attachment: tabbar.png

text blurry on tab titles.

Comment 6

[Aria Beingessner [:Gankra]]

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

Comment 7

[Aria Beingessner [:Gankra]]

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