The timingFunction of CAAnimation only allow us create a named or cubic-bezier CAMediaTimingFunction.Now the TFAnimation is a light weight implementation which enhance CABasicAnimation with custom timingFunction 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 TFAnimation folder to your project
• Use it just as CABasicAnimation except assign timeFunction with a block (CGFloat) -> CGFloat rather than assign 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
}

• There are some pre-defined time function for convience,see TFEasingFunction.swift.

• animations-explained
• RBBAnimation