AdditionalEvent "panleft" is fired when swiping down

[Sherl0ck007]

I have the case that there are two lines of text under the component that is supposed to be swipeable left or right. Now, if you mark the text in an upwards movement and release the mouse button in the swipeable component and swipe the component down directly after that, an additionalEvent panleft is fired. When you only swipe down the component, nothing happens like it is supposed to.

[jakewhelan]

I am experiencing this problem too. I have pan direction: Hammer.DIRECTION_HORIZONTAL so there should be no vertical pan detected.

This works as intended if deltaX !== 0, but when deltaX === 0 and you vertically pan, a panleft event is fired with a large deltaX. This is really hurting my hammer.js carousel implementation, we go to production soon.

Video demonstration incoming.

[jakewhelan]

Video demonstration: https://gyazo.com/dadccaf5375282c4eb9e619e2a0709a3

Reproduction conditions:

• Chrome 60
• Touch input (chrome emulator or mobile device)
• hammertime.on("pan", foo)

[bradenfcc]

Same issue here (using vertical pan). If I accidentally pan left or right at start, I get a massive spike in the deltaY and then it stops detecting deltaY until next touch.

EDIT: This also appears to only be an issue on Chrome (60). Works as intended on Firefox.

[glomotion]

Yikes. I can't believe hammer's still having these problems. I suspect this issue is related to a much older one:
#1050 (comment)

[jakewhelan]

We've done a hack in our implementation to mitigate this issue, it's not perfect but it is better.

In your pan event handler:

hammertime.on('pan', onPan)

...

const onPan = ({ center, whatever, else, you, need }) => {
  if (center.x === 0 && center.y === 0) return
  // do whatever you need to do 
}

[nickschot]

I'm also encountering this issue (using ember-gestures which uses hammerjs). Massive spike on velocity, deltaX (in my case) on a very small vertical pan.

Thanks for the workaround @jakewhelan . Was already wondering why center was 0,0 anyway.

[Luobata]

same problem with the vertical pan. The first time on vertical pan only trigger a event panleft with center.x = -1 center.y = 0. And the second time trigger 5times most.