1633276 - Transition of opacity not smooth

Status: RESOLVED FIXED

(Core :: Web Painting, defect)

Description

[alexander.fleischer]

User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:75.0) Gecko/20100101 Firefox/75.0

Steps to reproduce:

Hi created a jsbin:
https://jsbin.com/nimujucugo/edit?html,css,js,output

There is a link "Open Layer". By reducing the output window (400px or smaller) the transition is no longer smooth. I could reproduce this also on many examples on codepen.

Actual results:

The background appears / disappears immediately.

Expected results:

The background should appear smooth and by cklicking on the background it should disappear smooth.

Comment 1

[alexander.fleischer]

This is the right link to jsbin:

https://jsbin.com/hosasaboqa/edit?html,css,js,output

Comment 2

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

Bugbug thinks this bug should belong to this component, but please revert this change in case of error.

Comment 3

[Timothy Nikkel (:tnikkel)]

It only reproduces for me in jsbin, if I copy the contents into a standalone html file it seems to work fine.

regression range
https://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=1c235a552c32ba6c97e6030c497c49f72c7d48a8&tochange=f8acdf0185d786809bfbe8cabab081400dc47c68

verified by commenting out the lines from https://hg.mozilla.org/mozilla-central/rev/41dabd41e63e that this is from bug 1471174.

Comment 4

[Timothy Nikkel (:tnikkel)]

I think I've figured this out.

Comment 5

[Timothy Nikkel (:tnikkel)]

Attachment: Bug 1633276. Ensure that when IsFrameScrolledOutOfView calls nsLayoutUtils::TransformFrameRectToAncestor the ancestor frame is actually an ancestor. r?hiro

The SCROLLABLE_FIXEDPOS_FINDS_ROOT flag makes GetNearestScrollableFrame return the root scroll frame for fixed pos frames. Fixed pos frames are direct children of the root frame, which means that the frame we pass to TransformFrameRectToAncestor are not ancestors of each other in either direction.

So we treat fixed pos frames specially and don't pass that flag.

Comment 6

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/d578f391630a
Ensure that when IsFrameScrolledOutOfView calls nsLayoutUtils::TransformFrameRectToAncestor the ancestor frame is actually an ancestor. r=hiro

Comment 7

[Narcis Beleuzu [:NarcisB]]

Backed out for mochitest failures on test_restyles.html

Backout link: https://hg.mozilla.org/integration/autoland/rev/eef42d39ab68bc9b4f1e25194e1dc9d1fa298f9d
Log link: https://treeherder.mozilla.org/logviewer.html#/jobs?job_id=300595020&repo=autoland&lineNumber=1955

Comment 8

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/e2d84b2e5a7e
Ensure that when IsFrameScrolledOutOfView calls nsLayoutUtils::TransformFrameRectToAncestor the ancestor frame is actually an ancestor. r=hiro

Comment 9

[Andreea Pavel [:apavel]]

https://hg.mozilla.org/mozilla-central/rev/e2d84b2e5a7e