calcChord obbject missing properties crash

[secretrobotron]

https://github.com/Polymer/PointerGestures/blob/master/src/pinch.js#L141 causes a JS exception in Firefox Nightly. Somehow, https://github.com/Polymer/PointerGestures/blob/master/src/pinch.js#L135 always fails, because clientX and clientY are equivalent from a and b.

[secretrobotron]

Changing https://github.com/Polymer/PointerGestures/blob/master/src/pinch.js#L135 to if (d >= dist) { fixes the crash, but I'm not sure it's a valid solve.

[dfreedm]

Were you using touch in Firefox Nightly? I haven't tested that scenario. There could be some missing properties from their Touch implementation.

[secretrobotron]

AFAIK, no. I was just using a wireless trackpad for my macbook. Wouldn't be surprised if Firefox was missing some Touch properties, but I'm not sure it impacts the math here.

[bergie]

This might be the reason for jquery-archive/PEP#131. PointerGestures seem to crash the app quite a bit also with PhoneGap/Mobile Chrome Apps on KitKat.

[bergie]

@secretrobotron I just tried that patch on our mobile chrome app, and it definitely didn't help. We end up passing a lot of NaNs around

[secretrobotron]

@bergie interesting. Maybe there's another problem. The problem I noticed was on desktop, but it might manifest differently on mobile. Can you confirm that the values that are returned from calcChord are NaN? Maybe another branch should return 0s if certain conditions are not met.

[bergie]

@secretrobotron see some debugging data at jquery-archive/PEP#131 from @jonnor. We also provided an Android debug build of the app. But we'll be happy to debug further as needed.