1540988 - Doing CMD+two finger scroll to zoom breaks layout and looses sync with browser-fullZoom with apz.allow_zooming

Status: RESOLVED FIXED

(Core :: Panning and Zooming, defect, P3)

Description

[Mike de Boer [:mikedeboer]]

This is OSX-only (I'm currently on Mojave) AFAICT, using Firefox 67 Beta.

I've set OSX accessibility zoom to be activated using the '^ Ctrl' modifier.

Comment 1

[Mike de Boer [:mikedeboer]]

Sometimes I can only restore the state by closing the tab and opening a new one with the copied URL. Of course that way I lose my navigation history.

Comment 2

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

Can you describe in a bit more detail what your STR are? CMD+two finger scroll works fine for me on 67 beta on macOS.

Comment 3

[Mike de Boer [:mikedeboer]]

Of course:

Video of the issue in action: https://www.youtube.com/watch?v=m6W84nrjVcE&feature=youtu.be

STR:

1. Open this bug in a separate tab.
2. Hold the Command key while zooming in and out using the two-finger swipe gesture. (Watch the zoom percentage label updating)
3. Press Command+0 after a while to reset the zoom level to 100%

Expected the result:

The content snaps back to its correct zoom level and proper scroll position.

Actual result:

The content looks stuck at a certain zoom level that's always larger than normal. Also the scroll position is weirdly snapped back.

Might this be related to the virtual viewport at all?

Comment 4

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

Hm, interesting. I still cannot reproduce. When I change the zoom the page content remains centered in the window, whereas in your video even the first zoom out to 90% shifts it over to the right. Do you see the problem in a clean profile?

Comment 5

[Botond Ballo [:botond]]

(In reply to Mike de Boer [:mikedeboer] from comment #3)

Might this be related to the virtual viewport at all?

I don't think so, as that currently only affects mobile.

Comment 6

[Mike de Boer [:mikedeboer]]

Oh, on a new profile it doesn't happen to me indeed! I had 'apz.allow_zooming' set to true in this profile, which might be what broke it.

Comment 7

[Mike de Boer [:mikedeboer]]

Yep, can confirm that unsetting that pref fixed it for me. Please feel free to do whatever with this bug ;-)

Comment 8

[Botond Ballo [:botond]]

Let's make it block desktop zooming.

Comment 9

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

I think if we disable pinching while modifier keys are pressed, that should resolve this issue. The basic problem is that command+scroll can easily get turned into command+pinch and both have a somewhat-similar effect so the user may not realize they ended up doing a pinch instead of a reflow zoom.

Comment 10

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

Attachment: Bug 1540988 - Don't do trackpad-based pinch zooming if keyboard modifiers are present. r?botond

Comment 11

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/c9b542fa6957
Don't do trackpad-based pinch zooming if keyboard modifiers are present. r=botond

Comment 12

[Razvan Maries]

https://hg.mozilla.org/mozilla-central/rev/c9b542fa6957

Comment 13

[Ciprian Georgiu, Desktop QA]

Hi Mike! I've tried to reproduce this issue by following the steps from comment 3, while having the apz.allow_zooming pref set to true on an affected Nightly build 80.0a1 (20200720094507). Unfortunately, I was unable to see the behaviour described by you on macOS 10.14.

Would you mind confirming this fix on latest Beta 80, given the fact that I did not encounter the initial bug?