Xcode playground with live view to quickly test animations

CoreAnimation.swift

//: Playground - noun: a place where people can play

import UIKit
import XCPlayground

let aView = UIView(frame: CGRectMake(0, 0, 200, 200))
aView.backgroundColor = UIColor.whiteColor()

let aLayer = CALayer()
aLayer.bounds = CGRectMake(0, 0, 100, 100)
aLayer.position = aView.center
aLayer.backgroundColor = UIColor.blueColor().CGColor
aView.layer.addSublayer(aLayer)

aLayer.opacity = 1.0
dispatch_after(dispatch_time(DISPATCH_TIME_NOW, Int64(0.5 * Double(NSEC_PER_SEC))), dispatch_get_main_queue(), { () -> Void in
    
    // implicit
//    aLayer.transform = CATransform3DMakeRotation(CGFloat(M_PI_4), 0, 0, 1)
    
    // explicit
    let animation = CABasicAnimation()
    animation.keyPath = "transform"
    animation.fromValue = NSValue(CATransform3D: aLayer.transform)
    animation.toValue = NSValue(CATransform3D: CATransform3DMakeRotation(CGFloat(M_PI_4), 0, 0, 1))
    animation.duration = 1.0
    aLayer.transform = CATransform3DMakeRotation(CGFloat(M_PI_4), 0, 0, 1)
    aLayer.addAnimation(animation, forKey: "rotation")
})

XCPlaygroundPage.currentPage.liveView = aView