trigger animation on scroll position, iOS sometimes weird

[JohnnyRuvac]

Hi guys,

 

firstly, let me thank you for this fantastic animation platform. Discovering it was simply jaw-dropping experience that changed my life as a developer.

 

I am now playing around with page that will have multiple animations triggered on particular scroll position. I decided to not use any parallax plugins that work on mobile, because they appeared to be slow. Basically, I want to animate some DOM elements when they come in to the view. 

I tested it in all browsers and it works fine, even on iOS, but sometimes it is acting a bit weird. I have problems only on iOS. I haven't tested any android, i don't have any.

When you scroll slowly to the desired element, it animates just fine. But sometimes when you scroll faster, it appears in final position, but without an animation. Sometimes just part of an animation happens. I would like to understand whats going on there. Can you help me please, or at least point me to the right direction?

 

I am using latest version of GSAP, tested on iPhone 4 with iOS 6.1.3 and iPad 3. I was able to recreate the issue on iOS simulator as well. I am attaching example code.

 

Many thanks!

 

scrolltest.zip