1699451 - Double tap to zoom in on text then pictures focuses on wrong element

Status: VERIFIED FIXED

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

Description

[Daniel Cicas [:dcicas], Release QA]

Affected versions

• Fx 88.0a1 (Build ID: 20210318093109)

Affected platforms

• Mac OS Arm

Preconditions

• Have apz.mac.enable_double_tap_zoom_touchpad_gesture pref enabled

Steps to reproduce

1. Start Firefox.
2. Reach the following link
3. Double tap on the right table on some text (the one with the picture) so that the picture is also visible when zoomed in.
4. Double tap on the picture.

Expected result

• The second zoom in on the picture is a small zoom in and focus is on the picture.

Actual result

• The second zoom in is a large zoom and the focus is not where you double tapped.

Regression range
*I don’t think that this is a regression.

Additional notes

• A screencast of the issue is available here.
• issue can be reproduced quite reliably 4 out of 5 times.

Comment 1

[Romain Testard [:RT]]

Martin can you please help set a priority?

Comment 2

[Martin Balfanz [:mbalfanz]]

I can't reproduce this often myself, but it would be good to have a detailed look. Assigning a P3 for now.

Comment 3

[Timothy Nikkel (:tnikkel)]

The problem is here

https://searchfox.org/mozilla-central/rev/97b93cd3205023061d454cf4a270a7e66127310b/gfx/layers/apz/util/DoubleTapToZoom.cpp#147

where we use aPoint it is in visual coordinates but we add it to coords that are in layout coords, ie we need to divide aPoint by the resolution before adding it to things in layout coords. Not sure why this doesn't affect Android yet.

Comment 4

[Timothy Nikkel (:tnikkel)]

All dependant bugs are resolved now, this should be fixed.

Comment 5

[Daniel Cicas [:dcicas], Release QA]

Hello,

I can confirm this issue is verified fixed with 89.0a1 (BuildID: 20210414160838) on macOS 11.2 ARM.