1598735 - Incorrect rendering when combining -webkit-background-clip:text with background-attachment:fixed

Status: RESOLVED DUPLICATE of bug 1313757

(Core :: Web Painting, defect, P3)

Description

[Markus Stange [:mstange]]

Attachment: testcase 1

Steps to reproduce:

1. Load the attached testcase.
2. Scroll down slowly.

Expected results:
The text should move upwards as usual.

Actual results:
The text stays fixed and gets partially clipped.

This happens both with and without WebRender.

This bug was reported on https://twitter.com/LeaVerou/status/1197609676495622147 .

Comment 1

[Cristian Fogel [:cfogel]]

Regression range:

• Last good: 2016-04-15 changeset: afd82f887093e5e9e4015115ca5795ec82a6f732
• First bad: 2016-04-16 changeset: a5322c766f510d2a6544b519ffcc72a19879c779
• Pushlog URL
• Potential regressor: 1263516 looks like the potential culprit

An additional note is that on builds previous to the push, the container for the text was all black.

Comment 2

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

The priority flag is not set for this bug.
:mattwoodrow, could you have a look please?

For more information, please visit auto_nag documentation.

Comment 3

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

Bugbug thinks this bug is a regression, but please revert this change in case of error.

Comment 4

[Daniel Holbert [:dholbert]]

Attachment: testcase 2

Just ran into this when diagnosing a webcompat.com issue (https://webcompat.com/issues/47689 ) -- attaching my reduced testcase, which is slightly different from the original & helps you visualize the bug a bit clearer perhaps:

• my testcase doesn't use transparent text, so the actual text (lime) & the clipped-background (red) can be visualized separately.
• my testcase adds a border, which makes it clearer that artifacts do get cleaned up when they're outside the border-area (that's why the text starts to get "eaten" from the bottom in the original testcase).

Comment 5

[Daniel Holbert [:dholbert]]

This is not really a regression; it's just a bug in the implementation of background-clip:text, it seems (which was broken at least as far back as when it was preffed on).

--> removing regression keyword & adding association with bug 759568.

Comment 6

[Jonathan Kew [:jfkthame]]

Dupe of bug 1313757, afaics.