1511137 - Zoom isn't restored after exiting fullscreen

Status: RESOLVED FIXED

(Core :: Panning and Zooming, defect, P2)

Description

[csheany]

User Agent: Mozilla/5.0 (Android 7.1.1; Tablet; rv:65.0) Gecko/65.0 Firefox/65.0

Steps to reproduce:

1. Open https://www.mozilla.org/en-US/firefox/
2. Zoom in
3. Enter fullscreen of a video
4. Exit


Actual results:

The page is zoomed out


Expected results:

The page should still be zoomed in

Comment 1

[Botond Ballo [:botond]]

I can reproduce this intermittently. It looks like there may be a race condition between the code to restore the original zoom level that was added in bug 1493976, and some other code that is setting the zoom level.

Comment 2

[Botond Ballo [:botond]]

(In reply to Botond Ballo [:botond] from comment #1)
> and some other code that is setting the zoom level

Specifically, APZCCallbackHelper::UpdateRootFrame() [1].

[1] https://searchfox.org/mozilla-central/rev/8f0db72fb6e35414fb9a6fc88af19c69f332425f/gfx/layers/apz/util/APZCCallbackHelper.cpp#318

Comment 3

[Botond Ballo [:botond]]

We take this branch in NotifyLayersUpdated() [1] which has a comment that says:

  // Any change to the pres shell resolution was requested by APZ and is
  // already included in our zoom;

This is no longer true in light of bug 1493976.

[1] https://searchfox.org/mozilla-central/rev/8f0db72fb6e35414fb9a6fc88af19c69f332425f/gfx/layers/apz/src/AsyncPanZoomController.cpp#4323

Comment 4

[Botond Ballo [:botond]]

Attachment: Bug 1511137 - Track more accurately when the main thread originates a resolution change. r=kats

The tracking is done using nsAtom origins, similarly to how updates to the
scroll offset are tracked.

Currently, APZ still uses some heuristics to deduce that the main thread
originated a resolution change in some cases, but the intention is to try
to remove those and rely only on this mechanism in the furture.

Comment 5

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/79e8494d5df5
Track more accurately when the main thread originates a resolution change. r=kats

Comment 6

[Stefan Hindli [:stefan_hindli]]

https://hg.mozilla.org/mozilla-central/rev/79e8494d5df5

Comment 7

[Botond Ballo [:botond]]

Too late to uplift this on 64.