Custom segue animation DONE RIGHT (no post render flashing)

customsegueanimation.txt

class InitialLBPSegue: UIStoryboardSegue {
	
	override func perform() {
		var firstVCView = sourceViewController.view as UIView!
		var thirdVCView = destinationViewController.view as UIView!
		
		let window = UIApplication.sharedApplication().keyWindow
		window?.insertSubview(thirdVCView, belowSubview: firstVCView)
		
		thirdVCView.transform = CGAffineTransformScale(thirdVCView.transform, 0.001, 0.001)
		
		
		UIView.animateWithDuration(0.5, animations: { () -> Void in
			firstVCView.transform = CGAffineTransformScale(thirdVCView.transform, 0.001, 0.001)
			
			}) { (Finished) -> Void in
				
				UIView.animateWithDuration(0.5, animations: { () -> Void in
					thirdVCView.transform = CGAffineTransformIdentity
					
					}, completion: { (Finished) -> Void in
						
						firstVCView.transform = CGAffineTransformIdentity
						self.sourceViewController.presentViewController(self.destinationViewController as! UIViewController, animated: false, completion: nil)
				})
		}
	}
}