Closed Bug 1609022 Opened 4 years ago Closed 4 years ago

background-blend-mode does not blend a fixed first background-image with background-color

Categories

(Core :: Web Painting, defect)

defect
Not set
normal

Tracking

()

RESOLVED FIXED
mozilla74
Tracking Status
firefox-esr68 --- unaffected
firefox72 --- wontfix
firefox73 --- fixed
firefox74 --- fixed

People

(Reporter: go.shoemake, Assigned: mstange)

References

(Regression)

Details

(Keywords: regression)

User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:72.0) Gecko/20100101 Firefox/72.0

Steps to reproduce:

Load a webpage with a background-image, background-color, and background-blend-mode set, where the first (lowest) background image is fixed, as in the following CSS code:

html {
  background: fixed linear-gradient(to bottom, white, black), green;
  background-blend-mode: multiply;
}

Actual results:

The background-image did not blend with the background-color of the element.

Expected results:

The background-image should blend with the background-color of the element, as specified by Compositing and Blending Level 1, which makes no special provisions for fixed background images. This is the behaviour of Chrome.

I can confirm this issue using the latest Nightly 74.0a1 on Windows 10 x64, Ubuntu 18.04 and Mac OS X 10.15.

I managed to find a regression range, here are the results:

Found commit message:
Bug 1599606 - Don't interleave a non-scrolled canvas background color item and a fixed canvas background image with a scrolled background-color item. r=mattwoodrow

Status: UNCONFIRMED → NEW
Has Regression Range: --- → yes
Component: Untriaged → Web Painting
Ever confirmed: true
Keywords: regression
OS: Unspecified → All
Product: Firefox → Core
Regressed by: 1599606
Hardware: Unspecified → All
Version: 72 Branch → Trunk

Markus, do you have cycles to look at this? It's getting late in the Beta cycle for getting a fix into Fx73.

Flags: needinfo?(mstange)

Can you back out the offending changeset on central and beta? The small performance win doesn't warrant a regression in correctness.

Flags: needinfo?(mstange) → needinfo?(ryanvm)

Should bug 1599606 be reopened afterwards or wontfixed?

Flags: needinfo?(mstange)

Reopened, please. Thanks!

Flags: needinfo?(mstange)

This should be fixed in 73.0b9 and newer via backing out bug 1599606.

Assignee: nobody → mstange
Status: NEW → RESOLVED
Closed: 4 years ago
Flags: needinfo?(ryanvm)
Resolution: --- → FIXED
Target Milestone: --- → mozilla74
Regressions: 1611795
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