Animating on some part of UIBezier path - ios

Question

I have two UIBezierPath...
First path shows the total path from to and fro destination and the second path is a copy of the first path but that copy should be a percentage of the first path which I am unable to do.
Basically I would like the plane to stop at the part where green UIBezier path ends and not go until the past green color.
I am attaching a video in hte link that will show the animation I am trying to get. http://cl.ly/302I3O2f0S3Y
Also a similar question asked is Move CALayer via UIBezierPath
Here is the relevant code
override func viewDidLoad() {
super.viewDidLoad()
let endPoint = CGPointMake(fullFlightLine.frame.origin.x + fullFlightLine.frame.size.width, fullFlightLine.frame.origin.y + 100)
self.layer = CALayer()
self.layer.contents = UIImage(named: "Plane")?.CGImage
self.layer.frame = CGRectMake(fullFlightLine.frame.origin.x - 10, fullFlightLine.frame.origin.y + 10, 120, 120)
self.path = UIBezierPath()
self.path.moveToPoint(CGPointMake(fullFlightLine.frame.origin.x, fullFlightLine.frame.origin.y + fullFlightLine.frame.size.height/4))
self.path.addQuadCurveToPoint(endPoint, controlPoint:CGPointMake(self.view.bounds.size.width/2, -200))
self.animationPath = self.path.copy() as! UIBezierPath
let w = (viewModel?.completePercentage) as CGFloat!
// let animationRectangle = UIBezierPath(rect: CGRectMake(fullFlightLine.frame.origin.x-20, fullFlightLine.frame.origin.y-270, fullFlightLine.frame.size.width*w, fullFlightLine.frame.size.height-20))
// let currentContext = UIGraphicsGetCurrentContext()
// CGContextSaveGState(currentContext)
// self.animationPath.appendPath(animationRectangle)
// self.animationPath.addClip()
// CGContextRestoreGState(currentContext)
self.shapeLayer = CAShapeLayer()
self.shapeLayer.path = path.CGPath
self.shapeLayer.strokeColor = UIColor.redColor().CGColor
self.shapeLayer.fillColor = UIColor.clearColor().CGColor
self.shapeLayer.lineWidth = 10
self.animationLayer = CAShapeLayer()
self.animationLayer.path = animationPath.CGPath
self.animationLayer.strokeColor = UIColor.greenColor().CGColor
self.animationLayer.strokeEnd = w
self.animationLayer.fillColor = UIColor.clearColor().CGColor
self.animationLayer.lineWidth = 3
fullFlightLine.layer.addSublayer(shapeLayer)
fullFlightLine.layer.addSublayer(animationLayer)
fullFlightLine.layer.addSublayer(self.layer)
}
override func viewDidAppear(animated: Bool) {
super.viewDidAppear(animated)
updateAnimationForPath(self.animationLayer)
}
func updateAnimationForPath(pathLayer : CAShapeLayer) {
let animation : CAKeyframeAnimation = CAKeyframeAnimation(keyPath: "position")
animation.path = pathLayer.path
animation.calculationMode = kCAAnimationPaced
animation.delegate = self
animation.duration = 3.0
self.layer.addAnimation(animation, forKey: "bezierPathAnimation")
}
}
extension Int {
var degreesToRadians : CGFloat {
return CGFloat(self) * CGFloat(M_PI) / 180.0
}
}

Answer 1

Your animation for traveling a path is exactly right. The only problem now is that you are setting the key path animation's path to the whole bezier path:
animation.path = pathLayer.path
If you want the animation to cover only part of that path, you have two choices:
Supply a shorter version of the bezier path, instead of pathLayer.path.
Alternatively, wrap the whole animation in a CAAnimationGroup with a shorter duration. For example, if your three-second animation is wrapped inside a two-second animation group, it will stop two-thirds of the way through.