1929182 - Demo at https://codepen.io/amit_sheen/pen/KKLKyyQ doesnt render anything on the screen

Status: VERIFIED FIXED

(Core :: Web Painting, defect)

Description

[Mayank Bansal]

Go to https://codepen.io/amit_sheen/pen/KKLKyyQ

ER: Nothing draws on the screen. Though if you do a "ctrl + A" on the demo, the text is displayed.
AR: It should

Bisection:
Bug 1927315. Do not try to prerender during hit test display list building. r=layout-reviewers,emilio
Differential Revision: https://phabricator.services.mozilla.com/D226981

Comment 1

[Mayank Bansal]

Attachment: about:support

Comment 2

[BugBot [:suhaib / :marco/ :calixte]]

Set release status flags based on info from the regressing bug 1927315

Comment 3

[Timothy Nikkel (:tnikkel)]

Thanks for filing.

It seems that this was already pretty buggy, bug 1927315 just made it worse. Does that match what you see as well?

Comment 4

[Mayank Bansal]

yes, it matches with what i see too.

Comment 5

[Timothy Nikkel (:tnikkel)]

Thanks.

Okay, so there is an underlying pre-existing background-clip: text bug here (there are many existing background-clip: text bugs), and I just happened to disturb it a little worse. I'll restore us to the old less-buggy behaviour but still preserve the perf win of the original patch.

Comment 6

[Timothy Nikkel (:tnikkel)]

Attachment: Bug 1929182. Allow prerender for the GenerateGlyphMask case. r?#gfx-reviewers,#layout-reviewers

GenerateGlyphMask is used for background-clip: text, of which our implementation is pretty buggy. In fact, the testcase of this bug we ar buggy on even before the regressing bug, the regressing bug just made it worse. So we already didn't handle this situation properly and we happened to disturb it and make it worse. Let's just restore the old behaviour for the unusual background-clip: text case, but we still keep the win in display list building for all other (much more common) cases.

Comment 7

[Mayank Bansal]

(In reply to Timothy Nikkel (:tnikkel) from comment #5)

Thanks.

Okay, so there is an underlying pre-existing background-clip: text bug here (there are many existing background-clip: text bugs), and I just happened to disturb it a little worse. I'll restore us to the old less-buggy behaviour but still preserve the perf win of the original patch.

I have filed bug 1929473 to track the pre-existing bug with background-clip: text .

Comment 8

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/a0919cc4b424
Allow prerender for the GenerateGlyphMask case. r=jwatt

Comment 9

[agoloman]

https://hg.mozilla.org/mozilla-central/rev/a0919cc4b424

Comment 10

[Ardelean Oana, Desktop Test Engineering [:oardelean]]

Reproducible on a 2024-11-04 Nightly build on Windows 10.
Verified as fixed on Firefox Nightly 135.0a1 and Firefox 134.0b2 on Windows 10, macOS 14, Ubuntu 22.