Closed Bug 945634 Opened 8 years ago Closed 8 years ago

Async zooming of fixed position, aligned content has regressed


(Core :: Panning and Zooming, defect)

Not set



Tracking Status
firefox27 --- unaffected
firefox28 + fixed
firefox29 --- fixed


(Reporter: cwiiis, Assigned: roc)




(Keywords: regression)


(1 file)

It looks like the transform applied to fixed position content anchored to the bottom, right and/or top is applied twice now, as can be seen when zooming in at the given URL.

This seems to be a regression from either the fix in bug 941050 or bug 919144. Or maybe from some other bug (but I tested it prior to bug 919144 landing, and it was working then).

Let's track this, it makes async zooming of fixed content feel very weird/broken. I've only tested on Android, but this likely affects b2g and Metro too.
roc, looks like some significant user impact regression. Can you look into this or assign someone to with possible backout?
Flags: needinfo?(roc)
Assignee: nobody → roc
Flags: needinfo?(roc)
I do not see this on my Nexus S on trunk.

I see what looks like a bug involving the vertical position of the pink div when I'm scrolling up. It's unrelated to zooming in. Everything else looks OK.

Did this get fixed by something else?
Er, scrub that. I think I was testing the wrong build.
I think the problem is that anchor computation is busted.
Attached patch fixSplinter Review
Attachment #8346320 - Flags: review?(matt.woodrow)
The anchor point is in the layer's coordinate system, whose 0,0 is the top-left of the fixed-pos frame.
Attachment #8346320 - Flags: review?(matt.woodrow) → review+
Closed: 8 years ago
Resolution: --- → FIXED
Target Milestone: --- → mozilla29
Comment on attachment 8346320 [details] [diff] [review]

[Approval Request Comment]
Bug caused by (feature/regressing bug #): 919144
User impact if declined: broken fixed-pos elements when zooming on mobile
Testing completed (on m-c, etc.): a little manual testing
Risk to taking this patch (and alternatives if risky): very low risk
String or IDL/UUID changes made by this patch: none
Attachment #8346320 - Flags: approval-mozilla-aurora?
Attachment #8346320 - Flags: approval-mozilla-aurora? → approval-mozilla-aurora+
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