波紋っぽいやつを演出してみる

最近、アニメーション関連の作業をしなかったせいでやり方をすっかり忘れてしまいましたので
リハビリがてらに作ってみました。

    func viewHamon(size: CGFloat) -> UIImage{
        UIGraphicsBeginImageContext(CGRectMake(100, 100, size, size).size);

        let context: CGContextRef = UIGraphicsGetCurrentContext()!
        CGContextSaveGState(context)

        CGContextSetFillColorWithColor(context, UIColor.clearColor().CGColor)
        CGContextFillRect(context, self.view.frame)

        let x = CGFloat(size/2)
        let y = CGFloat(size/2)
        let r = CGFloat((size/2)-10)


        let path : CGMutablePathRef = CGPathCreateMutable()

        CGPathAddArc(path, nil, x, y, r, 0, CGFloat(M_PI*2), false)

        CGContextAddPath(context, path)
        CGContextSetStrokeColorWithColor(context,UIColor.blackColor().CGColor)
        CGContextDrawPath(context, CGPathDrawingMode.FillStroke)

        let image = UIGraphicsGetImageFromCurrentImageContext()

        CGContextRestoreGState(context)

        return image
    }


    override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
        super.touchesBegan(touches, withEvent: event)

        if let touch = touches.first {
            let location = touch.locationInView(self.view)

            for(var i:Int = 0; i<3; i++){

                let layer = CAShapeLayer()
                layer.frame = CGRectMake(location.x, location.y, 100, 100)
                layer.position = CGPointMake(location.x, location.y)
                let image = viewHamon(100)
                layer.contents = image.CGImage

                self.view.layer.addSublayer(layer)

                CATransaction.begin()
                CATransaction.setAnimationDuration(5.0)
                CATransaction.setCompletionBlock({
                    layer.removeFromSuperlayer()
                })


                let animation : CABasicAnimation = CABasicAnimation(keyPath: "transform.scale")
                animation.delegate = self
                animation.timingFunction = CAMediaTimingFunction(name:kCAMediaTimingFunctionEaseOut)

                animation.duration = 3
                animation.removedOnCompletion = false
                animation.fillMode = kCAFillModeForwards                
                animation.toValue = NSNumber(double: 2.0)


                let animation2 : CABasicAnimation = CABasicAnimation(keyPath: "opacity")
                animation2.delegate = self
                animation2.duration = 3
                animation2.removedOnCompletion = false
                animation2.fillMode = kCAFillModeForwards
                animation2.fromValue = NSNumber(double: 1.0)
                animation2.toValue = NSNumber(double: 0.0)

                let group : CAAnimationGroup = CAAnimationGroup()
                group.beginTime = CACurrentMediaTime() + Double(i)*0.35
                group.animations = [animation, animation2]
                group.removedOnCompletion = false
                group.fillMode = kCAFillModeBackwards

                layer.addAnimation(group, forKey: "scale")
                layer.opacity = 0.0
                CATransaction.commit()
            }

        }
    }

これだけ。