Two-fingered pan doesn't do a scroll until a pinch action is performed

RESOLVED FIXED in Firefox 50

Status

()

Core
Panning and Zooming
P3
normal
RESOLVED FIXED
2 years ago
2 years ago

People

(Reporter: kats, Assigned: kats)

Tracking

Trunk
mozilla52
All
Android
Points:
---

Firefox Tracking Flags

(firefox49 wontfix, firefox50 fixed, firefox51 fixed, firefox52 fixed)

Details

(Whiteboard: [gfx-noted])

MozReview Requests

()

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Attachments

(1 attachment)

If the user tries to pan with two fingers while keeping the fingers a constant distance apart (i.e. just sliding the two fingers down the screen but in the same position relative to each other), the APZ doesn't do any panning.

I suspect this is because we only do two-fingered panning once we enter the PINCH state and we don't enter the PINCH state until the spanChange exceeds a threshold value [1]. If the fingers are a constant distance apart, the span isn't changing and so the code doesn't get triggered. We should probably augment that to also check if the focus has moved beyond the threshold.

[1] http://searchfox.org/mozilla-central/rev/fd672b97f13aa83af5f04caa7b61bd443fb623e9/gfx/layers/apz/src/GestureEventListener.cpp#275
status-firefox49: --- → wontfix
status-firefox50: --- → wontfix
status-firefox51: --- → fix-optional
Ah, I've just been wondering about this, while testing bug 1180799. Good catch!
Comment hidden (mozreview-request)
Fix was pretty straightforward, so I might request uplift to beta as well.
status-firefox50: wontfix → fix-optional

Comment 4

2 years ago
mozreview-review
Comment on attachment 8799035 [details]
Bug 1308627 - Ensure that two-fingered pans scroll the page even if the span between the fingers doesn't change.

https://reviewboard.mozilla.org/r/84334/#review82936
Attachment #8799035 - Flags: review?(botond) → review+

Comment 5

2 years ago
Pushed by kgupta@mozilla.com:
https://hg.mozilla.org/integration/autoland/rev/3b0429208a35
Ensure that two-fingered pans scroll the page even if the span between the fingers doesn't change. r=botond

Comment 6

2 years ago
bugherder
https://hg.mozilla.org/mozilla-central/rev/3b0429208a35
Status: NEW → RESOLVED
Last Resolved: 2 years ago
status-firefox52: affected → fixed
Resolution: --- → FIXED
Target Milestone: --- → mozilla52
Comment on attachment 8799035 [details]
Bug 1308627 - Ensure that two-fingered pans scroll the page even if the span between the fingers doesn't change.

Approval Request Comment
[Feature/regressing bug #]: APZ
[User impact if declined]: when the user does a two-fingered pan (panning the page with two fingers down), the pan may not begin until the user's fingers move apart/closer together (i.e. in a "pinch" gesture). It is unexpected behaviour.
[Describe test coverage new/current, TreeHerder]: there are existing tests covering most of this code, but not this behaviour specifically.
[Risks and why]: very low risk, not much that can go wrong here.
[String/UUID change made/needed]: none
Attachment #8799035 - Flags: approval-mozilla-beta?
Attachment #8799035 - Flags: approval-mozilla-aurora?

Comment 8

2 years ago
Comment on attachment 8799035 [details]
Bug 1308627 - Ensure that two-fingered pans scroll the page even if the span between the fingers doesn't change.

Makes sense, Aurora51+, Beta50+
Attachment #8799035 - Flags: approval-mozilla-beta?
Attachment #8799035 - Flags: approval-mozilla-beta+
Attachment #8799035 - Flags: approval-mozilla-aurora?
Attachment #8799035 - Flags: approval-mozilla-aurora+
I'm hitting conflicts uplifting this patch to aurora. Do we need to uplift Bug 1298886 first? Or can you post a rebased patch?
Flags: needinfo?(bugmail)
Rebased and landed:

https://hg.mozilla.org/releases/mozilla-aurora/rev/9a452e8fde0ffd76d25179f5d6165265444a2247
https://hg.mozilla.org/releases/mozilla-beta/rev/79bb587bcd3dcf679d2c65a0afa11834d1a3f1e7
status-firefox50: fix-optional → fixed
status-firefox51: fix-optional → fixed
Flags: needinfo?(bugmail)
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