Create ovalInRect Curt round Red to draw

gistfile1.txt

public extension CGFloat {
    
    public func toRadians() -> CGFloat {
        return (self * CGFloat(M_PI)) / 180.0
    }
    
    public func toDegrees() -> CGFloat {
        return self * 180.0 / CGFloat(M_PI)
    }
    
}

 private var colorLayer:CALayer = {
        return CALayer()
    }()
    
    private var layerView : UIView = {
        return UIView(frame: CGRectMake(160,400,50,50))
    }()
    

  private let kRotationAnimation = "kRotationAnimation"
    
    private let shapeLayer = CAShapeLayer()
    private lazy var identityTransform: CATransform3D = {
        var transform = CATransform3DIdentity
        transform.m34 = CGFloat(1.0 / -500.0)
        transform = CATransform3DRotate(transform, CGFloat(-90.0).toRadians(), 0.0, 0.0, 1.0)
        return transform
    }()
    

 func shapeLayerTest(){
        
        self.view.addSubview(layerView)
        
        shapeLayer.lineWidth = 2.0
        shapeLayer.fillColor = UIColor.clearColor().CGColor
        shapeLayer.strokeColor = UIColor.redColor().CGColor
        shapeLayer.actions = ["strokeEnd" : NSNull(), "transform" : NSNull()]
        shapeLayer.anchorPoint = CGPoint(x: 0.5, y: 0.5)
        
        shapeLayer.frame = layerView.bounds
        
        let inset = shapeLayer.lineWidth / 2.0
        shapeLayer.path = UIBezierPath(ovalInRect: CGRectInset(shapeLayer.bounds, inset, inset)).CGPath
        shapeLayer.strokeEnd = min(0.9 * 100, 0.95) //处理画笔程度
        shapeLayer.transform = identityTransform    //处理角度
        layerView.layer.addSublayer(shapeLayer)
        
        if shapeLayer.animationForKey(kRotationAnimation) != nil { return }
        
        let rotationAnimation = CABasicAnimation(keyPath: "transform.rotation.z")
        rotationAnimation.toValue = CGFloat(2 * M_PI) +  currentDegree()
        rotationAnimation.duration = 1.5
        rotationAnimation.repeatCount = Float.infinity
        rotationAnimation.removedOnCompletion = false
        rotationAnimation.fillMode = kCAFillModeForwards
        shapeLayer.addAnimation(rotationAnimation, forKey: kRotationAnimation)
        
    }
    private func currentDegree() -> CGFloat {
        return shapeLayer.valueForKeyPath("transform.rotation.z") as! CGFloat
    }