898054 - Work - Fix panning while zoomed with APZC to get rid of bad jitter

Status: RESOLVED WORKSFORME

(Firefox for Metro Graveyard :: Pan and Zoom, defect)

Description

[Brian R. Bondy [:bbondy]]

1. Zoom in via (un)pinch
2. Start to pan

It works in general but you will notice pretty bad jittering/jumping.

Comment 1

[Brian R. Bondy [:bbondy]]

Attachment: Patch v1.

The extra setResolution call was causing the jumpy behavior. After I removed it it's equally smooth when panning zoomed and not zoomed.

Comment 2

[Matt Brubeck (:mbrubeck)]

Comment on attachment 782932 [details] [diff] [review]
Patch v1.

Could we do this by saving the scale and checking "if (scale != oldScale)"?

Comment 3

[Brian R. Bondy [:bbondy]]

(In reply to Matt Brubeck (:mbrubeck) from comment #2)
> Comment on attachment 782932 [details] [diff] [review]
> Patch v1.
> 
> Could we do this by saving the scale and checking "if (scale != oldScale)"?

That doesn't work but it prompted me to look into it more.
Strangely enough if I setResolution to always 1,1 then the problem goes away.
If I don't call it at all, as the original patch, the problem goes away.
Even a single call to the gfx's FrameMetrics zoom factor causes it.  

I asked kats to see what his thoughts were on how best to fix it.

Comment 4

[Brian R. Bondy [:bbondy]]

maybe it's supposed to be set to the dpi value zoom value?

Comment 5

[Brian R. Bondy [:bbondy]]

Comment on attachment 782932 [details] [diff] [review]
Patch v1.

A better fix for this is to take this code path for Metro, like Android does:
http://mxr.mozilla.org/mozilla-central/source/gfx/layers/composite/AsyncCompositionManager.cpp#663

But Kats and BenWa mentioned that Kat's new patches landing soon gets rid of a lot of this, so I'm obsoleting this patch for now and waiting for that to land for this bug.

Comment 6

[Allison Naaktgeboren :ally]

do we know approximately when kats new patches will land?

Comment 7

[Brian R. Bondy [:bbondy]]

See bug 899810, short story is that they landed but it broke APZC in Metro more.  He's working on it now and has a device that Marco hand delivered to him :)

Comment 8

[Brian R. Bondy [:bbondy]]

This is really hard to test due to fallout from bug 866232, but the jitter/jumpiness when zoomed seems gone when I can test it. Please re-open if you still see this.

Comment 9

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

With the patch on bug 901339 applied, the focal point of zooming appears to be fixed and I can test this bug again. I don't see the same jumpiness as I was seeing before, but I think there is still something wrong. Specifically, after I zoom in the content remains blurry, and doesn't get repainted at high-res. This is usually a result of the setResolution not getting called, or called on a window where it has no effect. I'm not sure if you want to track that in this bug or in a new bug but it's definitely something that needs to be corrected.

Comment 10

[Brian R. Bondy [:bbondy]]

I'll post a new bug for that, thanks for checking.