746120 - Pinch-zooming inwards on pages "separate" them from underlying canvas when a hidden overflow is used

Status: VERIFIED FIXED

(Firefox for Android Graveyard :: General, defect)

Description

[Aaron Train [:aaronmt]]

Attachment: Nightly (04/17) - Screenshot

Currently on DuckDuckGo when one pinch-zooms outwards, the page "separates" from it's underlying white blank canvas. This is evident in the attached screenshot.

--
Samsung Galaxy Nexus (Android 4.0.4)
Nightly (04/17)

Comment 1

[Kevin Brosnan [Ex-Mozilla]]

qawanted to get a reduced test case for ddg

Comment 2

[Aaron Train [:aaronmt]]

Attachment: testcase

Pinch-zoom outwards with this test-case and see the layout separation

Comment 3

[Tony Chung [:tchung]]

removing qawanted now that testcase has been added.

Comment 4

[Aaron Train [:aaronmt]]

Looks like the hidden overflow is the issue here?

Comment 5

[JP Rosevear [:jpr]]

Let us know if this is tricky and needs beta testing instead.

Comment 7

[Timothy Nikkel (:tnikkel)]

If you give the html element a background color then the bottom right rectangle stays white, so I'm wondering what exactly it is.

Comment 8

[Jet Villegas (inactive)]

user-scalable=no is supposed to prevent any zooming per:
https://developer.mozilla.org/en/Mobile/Viewport_meta_tag

Did we break that recently? Regression window please.

Comment 9

[Timothy Nikkel (:tnikkel)]

The bug happens without user-scalable=no so that is a separate issue.

Comment 10

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

(In reply to Jet Villegas (:jet) from comment #8)
> user-scalable=no is supposed to prevent any zooming per:
> https://developer.mozilla.org/en/Mobile/Viewport_meta_tag
> 
> Did we break that recently? Regression window please.

Yes, that is currently broken. Bug 707571 is tracking it. However as :tn said, that is a separate issue.

Comment 11

[Cristian Nicolae (:xti)]

Good build: 03/17

Bad build: 03/18

Possible regression range: 
http://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=ecaad3ae9964&tochange=e94edfdb1f5b

--
Device: Samsung Galaxy S (Captivate)
OS: Android 2.2

Comment 12

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

Attachment: Patch

(In reply to Timothy Nikkel (:tn) from comment #7)
> If you give the html element a background color then the bottom right
> rectangle stays white, so I'm wondering what exactly it is.

I've been investigating this issue indirectly via bug 735652 and bug 748526, and I believe that white rectangle is drawn by Java. By commenting out various lines in this function: http://mxr.mozilla.org/mozilla-central/source/mobile/android/base/gfx/LayerRenderer.java#574 I was able to make it go away. In latest m-c code the white rectangle is drawn by the checkerboard layer; if you comment that out it will turn black because it a "hole" in the background layer; if you comment out the line that sets the mask on the background layer the hole is filled in.

The attached patch that removes the "separation" of the layers by ensuring that the gecko root layer is transformed even if it is not scrollable.

Comment 13

[Ali Juma [:ajuma]]

Comment on attachment 618686 [details] [diff] [review]
Patch

Review of attachment 618686 [details] [diff] [review]:
-----------------------------------------------------------------

Transforming the root layer when it's not scrollable may cause other weirdness (since we don't have a displayport set in that situation). But it seems the right approach is to take this fix, and then get follow-up fixes for the other problems.

Comment 14

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

https://hg.mozilla.org/integration/mozilla-inbound/rev/1cc5c7879c82

Comment 15

[Ed Morley [:emorley]]

https://hg.mozilla.org/mozilla-central/rev/1cc5c7879c82

Comment 16

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

Comment on attachment 618686 [details] [diff] [review]
Patch

[Approval Request Comment]
Regression caused by (bug #): OMTC
User impact if declined: on pages with frameset or an overflow:hidden body, pinch zooming leaves the page anchored to the top-left of the screen with another white rect moving around
Testing completed (on m-c, etc.): tested locally, should probably bake on m-c for a day or two
Risk to taking this patch (and alternatives if risky): could expose other, worse, behaviour on overflow:hidden pages but i'd say low-risk.
String changes made by this patch: none

Comment 17

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

https://hg.mozilla.org/releases/mozilla-aurora/rev/1b143c452318

Comment 18

[IU]

Is there any possibility of this having caused bug 749658?

Comment 19

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

(In reply to IU from comment #18)
> Is there any possibility of this having caused bug 749658?

No, this is a mobile-only change.

Comment 20

[JP Rosevear [:jpr]]

On duckduckgo.com with the following build:
ftp://ftp.mozilla.org/pub/mobile/tinderbox-builds/mozilla-aurora-android/1335647503/

There is a black background you can see when you pinch zoom out.  Is this expected (ie the ignoring the user-scalable piece).

Comment 21

[Aaron Train [:aaronmt]]

(In reply to JP Rosevear [:jpr] from comment #20)
> On duckduckgo.com with the following build:
> ftp://ftp.mozilla.org/pub/mobile/tinderbox-builds/mozilla-aurora-android/
> 1335647503/
> 
> There is a black background you can see when you pinch zoom out.  Is this
> expected (ie the ignoring the user-scalable piece).

Filed bug 749741; it needs attention

Comment 22

[Cristian Nicolae (:xti)]

This issue doesn't occur anymore on the latest Nightly and Aurora builds. Closing bug as verified fixed on:

Firefox 15.0a1 (2012-05-29)
Firefox 14.0a2 (2012-05-29)

Device: Galaxy Nexus
OS: Android 4.0.2