1230085 - White checkerboarding visible (instead of page background)

Status: RESOLVED INCOMPLETE

(Firefox for Android Graveyard :: Toolbar, defect)

Description

[Gian-Carlo Pascutto [:gcp]]

Attachment: 2015-12-03 09.35.16.png

Nexus 7 2013, Android 5.1.1, todays Nightly. All of the below are regressions in this Nightly.

I tested on this URL: http://www.pianoworld.com/forum/ubbthreads.php/topics/1215363/15.html

Issue observed:

Scroll the page quickly. You can occasionally see white checkerboarding, despite the background color being known.

Comment 1

[Kartikaya Gupta (email:[e-mail])]

Thanks for filing these all as separate bugs!

For this one, the checkerboarding you see - is it a strip at the bottom of the page the same height as the url bar?

Comment 2

[Gian-Carlo Pascutto [:gcp]]

Kats, see the attached screenshot. It's way bigger.

This page has always had pretty bad performance, but I don't remember seeing white checkerboards, just ones in the page background color.

Comment 3

[James Willcox (:snorp) ([e-mail]) (he/him)]

I see the page background color here...

Comment 4

[Kartikaya Gupta (email:[e-mail])]

(In reply to Gian-Carlo Pascutto [:gcp] from comment #2)
> Kats, see the attached screenshot. It's way bigger.

Oh, sorry - I didn't see that when I loaded the bug initially. Yeah, that's weird. I'm also seeing the page background color.

Can you set the pref "apz.highlight_checkerboarded_areas" to true and see if the white area turns pink? If so then it's definitely checkerboarding and we're not getting the right layer color; if it stays white then it's something else and not actually checkerboarding.

Comment 5

[Gian-Carlo Pascutto [:gcp]]

With that pref I can get both white, brown and pink areas on the screen :-)

The white parts are most easily visible for me when the page is loading, and you scroll (or attempt to) into the not-drawn-yet part of the page. But it also happens when scrolling up.

If I had to describe it, it's as if we get a single frame of white just before the rendering "fills in" the part that we get to see.

Comment 6

[Gian-Carlo Pascutto [:gcp]]

Attachment: 2015-12-03 15.32.53.png

This is with the pref set, and the page fully loaded. Usually the brown or white rectangles are full-width, but this one wasn't.

Look as if we're seeing the page while its halfway rendered?

Comment 7

[Kartikaya Gupta (email:[e-mail])]

(In reply to Gian-Carlo Pascutto [:gcp] from comment #0)
> Nexus 7 2013, Android 5.1.1, todays Nightly. All of the below are
> regressions in this Nightly.

By "todays" do you mean Dec 2 or Dec 3? Specifically I'm wondering if your build has the patch from bug 1198021. That might help with the white flashing, maybe.

Comment 8

[Kartikaya Gupta (email:[e-mail])]

(In reply to Gian-Carlo Pascutto [:gcp] from comment #6)
> Created attachment 8695309 [details]
> 2015-12-03 15.32.53.png
> 
> This is with the pref set, and the page fully loaded. Usually the brown or
> white rectangles are full-width, but this one wasn't.
> 
> Look as if we're seeing the page while its halfway rendered?

This might be a possible effect from the progressive painting code, which aborts drawing when it discovers it's drawing stuff that won't be seen by the user. I'm just guessing though.

Comment 9

[Gian-Carlo Pascutto [:gcp]]

I'm seeing it both in yesterdays and todays (got an update about 1h ago).

Comment 10

[Gian-Carlo Pascutto [:gcp]]

I think the people in bug 1213873 are reporting very similar things.

Comment 11

[Kartikaya Gupta (email:[e-mail])]

Bug 1213873 has two issues getting conflated. Everything prior to comment 24 is pre-APZ and is something unrelated to this. In comment 24 the bottom two screenshots looks like normal checkerboarding (the background on that page is white) and low-res painting. The top two screenshots look like either progressive paint aborting or the main issue of bug 1213873. I don't think there's an issue on theverge.com with the checkerboarding being the wrong color at least.

Comment 12

[BMO Automation]

We have completed our launch of our new Firefox on Android. The development of the new versions use GitHub for issue tracking. If the bug report still reproduces in a current version of [Firefox on Android nightly](https://play.google.com/store/apps/details?id=org.mozilla.fenix) an issue can be reported at the [Fenix GitHub project](https://github.com/mozilla-mobile/fenix/). If you want to discuss your report please use [Mozilla's chat](https://wiki.mozilla.org/Matrix#Connect_to_Matrix) server https://chat.mozilla.org and join the [#fenix](https://chat.mozilla.org/#/room/#fenix:mozilla.org) channel.