Animating CAShapeLayer size change

Question

I am drawing a circle, with an initial radius of 200

self.circle = [CAShapeLayer layer];
self.circle.fillColor = nil;
self.circle.strokeColor = [UIColor blac         


        

Answer 1

Here is a direct swift conversion of Jonathan's code should anyone need it.

func scaleShape(shape : CAShapeLayer){

    let newRadius : CGFloat = 50;

    let newPath: UIBezierPath = UIBezierPath(arcCenter: CGPointMake(newRadius, newRadius), radius: newRadius, startAngle: (CGFloat(-M_PI) / 2.0), endAngle: (3 * CGFloat(M_PI) / 2), clockwise: true);


    let newBounds : CGRect = CGRect(x: 0, y: 0, width: 2 * newRadius, height: 2 * newRadius);
    let pathAnim : CABasicAnimation = CABasicAnimation(keyPath: "path");

    pathAnim.toValue = newPath.CGPath;

    let boundsAnim : CABasicAnimation = CABasicAnimation(keyPath: "bounds");
    boundsAnim.toValue = NSValue(CGRect: newBounds);

    let anims: CAAnimationGroup = CAAnimationGroup();
    anims.animations = [pathAnim, boundsAnim];
    anims.removedOnCompletion = false;
    anims.duration = 2.0;
    anims.fillMode = kCAFillModeForwards;

    shape.addAnimation(anims, forKey: nil);
}