1200684 - Rendering issues with opacity: using skia in Nightly

Status: RESOLVED FIXED

(Core :: Graphics, defect)

Description

[John Drinkwater (:beta)]

Attachment: Screenshot.2015-09-01.170701.png

User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:42.0) Gecko/20100101 Firefox/42.0
Build ID: 20150831004018

Steps to reproduce:

Visited https://steamlug.org/mumble in 43.0a1 with gfx.content.azure.backends set to skia


Actual results:

The Mumble list of users uses css opacity to make channels and subchannels less intense. However with the skia renderer, this is making the background darker as well.


Expected results:

Unlike Firefox with cairo, and Chromium, this appears incorrect.

Comment 1

[John Drinkwater (:beta)]

Attachment: small-testcase.html

Put together an offline reproduction of that behaviour

Comment 2

[Benoit Girard (:BenWa)]

Tentatively hanging this off bug 1007702 as well in case it's not Linux specific.

Comment 3

[Lee Salzman [:lsalzman]]

Upstream bug report with proposed fix: https://codereview.chromium.org/2097883002

Comment 4

[Lee Salzman [:lsalzman]]

Attachment: revise Skia row blits to preserve color when blended against itself

This is a port of work I did in upstream Skia to fix this issue: https://skia.googlesource.com/skia/+/40254c2c2dc28a34f96294d5a1ad94a99b0be8a6

Also some tests needed to be fuzzed due to the slight differences in blending.

Comment 5

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/mozilla-inbound/rev/ffd7f9c1bbf9
revise Skia row blits to preserve color when blended against itself. r=mchang

Comment 6

[Phil Ringnalda (:philor)]

https://hg.mozilla.org/mozilla-central/rev/ffd7f9c1bbf9