1425016 - Wikipedia icon rendered incorrectly

Status: NEW

(Core :: Graphics: ImageLib, defect, P3)

Description

[Thomas Bertels]

Attachment: Screenshot of the favicon since Firefox 52

Since Firefox 52, the Wikipedia icon (favicon) is rendered incorrectly : there are two points above each side of the W.

To reproduce: open https://www.wikipedia.org and check the tab icon.

Works in Firefox 51, broken in Firefox 52.

Regression window: https://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=8002299dfc3fb3b2c53e50e40a8e16f8dff2c3e7&tochange=c44c01dfd264370c1558b747525d220a9a89b51c

Comment 1

[Andre Klapper]

Cannot reproduce in Firefox 56 on Fedora 27.

Comment 2

[Timothy Nikkel (:tnikkel)]

Hmm, I get a different regression range

https://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=3587b25bae302c1eed72968dbd7cef883e715948&tochange=efe7d026ac641759838dd3897c37892e37e5b244

Comment 3

[Thomas Bertels]

(In reply to Timothy Nikkel (:tnikkel) from comment #2)

Here's an excerpt of mozregression:

C:\Users\Utilisateur>mozregression -g 51 -b 52
 0:00.15 INFO: bits option not specified, using 64-bit builds.
 0:00.15 INFO: Using date 2016-11-14 for release 52
 0:00.18 INFO: Using date 2016-09-19 for release 51

So I can't see how it could narrow it down to between 2016-03-22 and 2016-03-23.

By the way, here's the narrower window given by the command line version:
https://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=a7c654513f2ffd9d9ef38fa2bf512b9e8dae3cdd&tochange=c44c01dfd264370c1558b747525d220a9a89b51c

Comment 4

[Timothy Nikkel (:tnikkel)]

Ah, I think I understand this now. If I apply my patch from bug 1404366 that fixes the problem. So the non-premultiplied data must be causing this.

In my regression range is

  Bug 1207332. Enable skia content on OS X.

and I'm on OS X. skia doesn't handle non-premultied data as well as cairo did.

In your regression range there is

  Enable the GPU process for Nightly Windows users. (bug 1314133

which seems plausible for changing how non-premultied data is handled.

Comment 5

[Thomas Bertels]

That's great news! Let's hope it fixes it on Windows too.

Comment 6

[Milan Sreckovic [:milan] (needinfo for best results)]

Is this gone now that bug 1404366 is fixed?

Comment 7

[Thomas Bertels]

Attachment: Screenshot of the favicon since Firefox 59

It's better (see screenshot) but not yet fixed.

Comment 8

[Timothy Nikkel (:tnikkel)]

I think that is an artifact of using high quality downscaling on a 1-bit alpha mask (so we get alpha values other than 0 and 255) on an image that is designed to expect only 0 or 255 alpha.

Perhaps we should just turn off downscaling of ICOs that have an AND mask?