The timingFunction of CAAnimation only allows us to create a named or cubic-bezier CAMediaTimingFunction. TFAnimation is a light weight implementation which enhances CABasicAnimation with a custom timeFunction whose domain should be between 0 and 1, like cubic-bezier.

A simple sin-curve-like animation with timingFunction of f(t) = sin (4π * t)

• Drag TFBasicAnimation.swift to your project
• Use it just as you would CABasicAnimation, but assign timeFunction a (CGFloat) -> CGFloat closure, rather than assigning timingFunction.

let animationY = TFBasicAnimation()
animationY.keyPath = "position.y"
animationY.fromValue = 0
animationY.byValue = height / 4
animationY.duration = 5.0
animationY.timeFunction = {
  t in
  return t * t
}

• Several standard pre-defined timing functions (quadEaseInOut, cubicEaseInOut, etc.) are included in the class.

• animations-explained
• RBBAnimation