Do I need ScrollMagic to use GSAP?

[OSUblake]

Great demo Shaun! 

 

 

Once I have that, I will animate better than Looney Tunes and I will do it all with GSAP.  I will be heralded and win many prizes and do GSAP proud.

 

    Love it!

 

Here's your guide to not using jQuery...

http://youmightnotneedjquery.com

 

For element visibility, you can use element.getBoundingClientRect(). It returns the coordinates of the element relative to the screen, even if it's transformed.

var rect = myElement.getBoundingClientRect();
var vh = window.innerHeight;

if (rect.top >= 0 && rect.bottom <= vh) {
  // Fully visible
}

if (rect.top + rect.height >= 0 && rect.bottom - rect.height <= vh) {
  // Partially visible
}

Listening for "touchmove" and "scroll" events should fix the iOS problem. You need to be careful about how you do scroll events as they can be a performance killer. I would recommend using TweenLite.ticker to run the scroll event updates as it will throttle the calls.

 

Checking the visibility on 600 elements.

See the Pen 0d4742d2200d028ed42297cb874af2b5?editors=0010 by osublake (@osublake) on CodePen