706615 - Panning motion slows, then jerks

Status: VERIFIED FIXED

(Firefox for Android Graveyard :: General, defect, P1)

Description

[Johnathan Nightingale [:johnath]]

Our current panning code seems to have ease-out/deceleration physics where it comes to a rest as the panning action completes. However, rather than coming to rest, it decelerates towards zero, and then jumps to a final position a bit further along the panning path.

It seems like we'd want panning to smoothly come to a stop - the jerk at the end feels wrong.

Dupe? Phone-specific? (I'm on a galaxy s2, latest nightly)

Comment 1

[Patrick Walton (:pcwalton)]

I'm pretty sure this is due to some combination of Gecko being slow to paint, CPU contention between Gecko and the compositor, and texture upload. Taking this bug since it's basically what I've been working on for the past few days.

Comment 2

[Patrick Walton (:pcwalton)]

Actually, I think this specific bug is a regression that some of kats' work introduced. CC-ing him.

Comment 3

[Patrick Walton (:pcwalton)]

The problem is changeset 4e745f151abd (bug 705114).

Comment 4

[Patrick Walton (:pcwalton)]

Yeah, this is a massive pain. If we can't rely on devices having sane touch events, I guess we should just use the system gesture detectors, which presumably have been tested by the manufacturer.

Comment 5

[Patrick Walton (:pcwalton)]

Attachment: WIP patch.

Here's a WIP patch. Should basically be a rebased version of your (Cwiiis') patch from earlier that switched to gesture detectors. This regresses clicking on links, so it can't land as is, but it should be the basic idea.

Comment 6

[Chris Lord [:cwiiis]]

Comment on attachment 578182 [details] [diff] [review]
WIP patch.

Review of attachment 578182 [details] [diff] [review]:
-----------------------------------------------------------------

Good other than what's noted below. I'd have thought that combined with wesj's patch in bug #704579 that just went in, this should solve that tapping links no longer works.

::: mobile/android/base/ui/PanZoomController.java
@@ +249,3 @@
>          if (mState == PanZoomState.PANNING_LOCKED) {
>              // check to see if we should break the axis lock
> +            double angle = Math.atan2(distanceY, distanceX);    // range [-pi, pi]

This is not equivalent to what was there before - distanceX,distanceY are the distances moved since the last call to onScroll, where this expects the distance moved since the first touch event.

@@ -454,5 @@
>              PLUS,       // Overscrolled in the positive direction
>              BOTH,       // Overscrolled in both directions (page is zoomed to smaller than screen)
>          }
>  
> -        public float firstTouchPos;             /* Position of the first touch event on the current drag. */

We probably still want firstTouchPos for the comment above.

Comment 8

[Chris Lord [:cwiiis]]

Taking this - will have a fix soon.

Comment 9

[Chris Lord [:cwiiis]]

Attachment: Fix jerk after fling

This patch fixes the issue for me on my Galaxy Nexus.

Comment 10

[Chris Lord [:cwiiis]]

http://hg.mozilla.org/projects/birch/rev/559d132a200e

Comment 11

[Aaron Train [:aaronmt]]

Samsung Galaxy SII (Android 2.3.4)
20111202040206
http://hg.mozilla.org/projects/birch/rev/e2a54aafac18