842091 - Cards view sometimes flickers white when opened while app other than homescreen is foreground

Status: VERIFIED FIXED

(Firefox OS Graveyard :: Gaia::System, defect)

Description

[Chris Jones [:cjones] inactive; ni?/f?/r? if you need me]

STR
 (1) Launch dialer, then settings, then email, then calendar, leaving calendar in the foreground
 (2) Long-press HOME to open cards view

The card for calendar flickers white before showing screenshot(?).

Comment 1

[Chris Jones [:cjones] inactive; ni?/f?/r? if you need me]

When the homescreen is foreground, we get bug 837350.

Comment 2

[Chris Jones [:cjones] inactive; ni?/f?/r? if you need me]

The problem seems to be that the foreground app is setVisible(false) before the cards view is ready.

Comment 3

[Chris Jones [:cjones] inactive; ni?/f?/r? if you need me]

This doesn't appear to be gaia's fault; the frame is setVisible(false) in the same CSS "transaction" that removes the white background.  I think the problem is that the app throwing out its layers is racing to the compositor with the window-manager layer transaction that removes the background.  When the app wins, we get the flicker.

Comment 4

[Chris Jones [:cjones] inactive; ni?/f?/r? if you need me]

Attachment: Prevent flickering when transitioning to cards view

This is a pretty gross hack, though not the grossest I've ever written.  Fixing it "for reals" would be too risky to consider for a v1.0 uplift.

The UX improvement is fantastic!  It's amazing how you get inured to these kinds of bugs.

jlebar, do you think this will negatively impact any of the app-launching fixes you've made?  This will keep apps in the fg class for an extra 50ms when they're sent to the background.

Comment 5

[Justin Lebar (not reading bugmail)]

Comment on attachment 714857 [details] [diff] [review]
Prevent flickering when transitioning to cards view

Is the homescreen visible when you're in cards view?  If so, there's a chance that this will cause us to kill the homescreen.

But it's probably fine.  I don't think there's any impact on the app-launching stuff, if this 50ms delay applies only when we're showing cards view.

Comment 6

[Chris Jones [:cjones] inactive; ni?/f?/r? if you need me]

The homescreen becomes visible during this transition, but it's already setVisible(true) before we setVisible(false) the transitioning app, so this patch won't affect that.

I filed bug 842102 on what we need to actually fix this bug.

Comment 7

[Chris Jones [:cjones] inactive; ni?/f?/r? if you need me]

Comment on attachment 714857 [details] [diff] [review]
Prevent flickering when transitioning to cards view

I'm going to go ahead and this through approval triage.

This is a very low-risk change that fixes a major visually jarring glitch when entering the cards view.

Comment 8

[Michael Vines [:m1] [:evilmachines]]

omgthatssomuchbetter

Comment 9

[(inactive after 6/18) Alive Kuo [:alive]]

Comment on attachment 714857 [details] [diff] [review]
Prevent flickering when transitioning to cards view

Review of attachment 714857 [details] [diff] [review]:
-----------------------------------------------------------------

Simple workaround and may be a race condition but if we have no better way before paint event is fired to system app... r=me.

Comment 10

[Tim Guan-tin Chien [:timdream] (please needinfo)]

Comment on attachment 714857 [details] [diff] [review]
Prevent flickering when transitioning to cards view

r+ if this fixes the problem. If you want the hack only apply to cards view opening, considering add

if (screenElement.classList.contains('cards-view'))

Also, Would you file a bug and attach the # to the comment so we could hopefully remove the hack one day?

Comment 11

[Chris Jones [:cjones] inactive; ni?/f?/r? if you need me]

The followup is bug 842102, but I'll add a comment in the code.

Comment 12

[Chris Jones [:cjones] inactive; ni?/f?/r? if you need me]

https://github.com/mozilla-b2g/gaia/commit/22e926333fdd1467ebaace0f835aedc721c06fc9

Comment 14

[Vivien Nicolas (:vingtetun) (:21) - (NOT reading bugmails, needinfo? please)]

Comment on attachment 714857 [details] [diff] [review]
Prevent flickering when transitioning to cards view

Let's say that I really don't like this solution and it is a shame for me to a+ it. But I have been told by all people that have tried the phone that this white flash is ugly and that the phone feels broken because of it and users wins.

This is a very low risk patch that should land on both v1.0.1 and v1-train

Comment 15

[Chris Jones [:cjones] inactive; ni?/f?/r? if you need me]

Bug 842102 won't be hard to fix, but we shouldn't take that for v1.0.

Comment 16

[John Ford [:jhford] CET/CEST Berlin Time]

v1-train@7c2b9afc7601ae7a925ea97bfa0fb1be1639f739

Comment 17

[Chris Jones [:cjones] inactive; ni?/f?/r? if you need me]

(In reply to Vivien Nicolas (:vingtetun) (:21) from comment #14)
> Comment on attachment 714857 [details] [diff] [review]
> Prevent flickering when transitioning to cards view
> 
> This is a very low risk patch that should land on both v1.0.1 and v1-train

This seems to have only landed on v1-train.

Comment 18

[Jonas Sicking (:sicking) No longer reading bugmail consistently]

I think the rule of the week is that only tef+ bugs get to be uplifted to the 1.0.1 release. So I'd expect that that is what people are querying for when looking for what to uplift.

Comment 19

[Lukas Blakk [:lsblakk] use ?needinfo]

Approving low risk fix for uplift.

Comment 20

[John Ford [:jhford] CET/CEST Berlin Time]

v1-train: 7c2b9afc7601ae7a925ea97bfa0fb1be1639f739
v1.0.1: c92d592e77ec11323ad2b1e11be6f5c1157982f7

Comment 21

[Cody Roesch [:croesch]]

Unagi Build ID: 20130313070202
Gecko: http://hg.mozilla.org/releases/mozilla-b2g18_v1_0_1/rev/e74dafa6b2d9
Gaia: b34e726147f8e671ad8c538b50900ccfbffcb084
Kernel: Dec 5th

In the build above, I'm unable to get the bug to occur. I've opened up a a bunch of programs and gone into card view from inside multiple programs but also just on different home screens and not seen this flash.

Marking this as Verified Fixed.