swift - 圆形比例动画效果有点奇怪

Question

我正在为我的 GMSMarker 制作动画，以便它在几秒钟内脉冲一次。

func addWave()
    {
//        circleView.layer.cornerRadius = size / 2

        //Scale
        let scaleAnimation = CABasicAnimation(keyPath: "transform.scale")
        scaleAnimation.fromValue = 1
        scaleAnimation.toValue = zoom

        //Opacity
        let alphaAnimation = CABasicAnimation(keyPath: "opacity")
        alphaAnimation.toValue = 0.0

        //Corner radius
//        let cornerRadiusAnimation = CABasicAnimation(keyPath: "cornerRadius")
//        cornerRadiusAnimation.fromValue = size / 2
//        cornerRadiusAnimation.toValue = (size * zoom)/2

        //Animation Group
        let animations: [CAAnimation] = [scaleAnimation, alphaAnimation]

        let animationGroup = CAAnimationGroup()
        animationGroup.duration = duration
        animationGroup.animations = animations
        animationGroup.timingFunction = CAMediaTimingFunction(name: kCAMediaTimingFunctionEaseOut)
        animationGroup.repeatCount = 1
        animationGroup.fillMode = kCAFillModeForwards
        animationGroup.isRemovedOnCompletion = false
        circleView.layer.add(animationGroup, forKey: "group")
    }

结果是这样的:

如果我取消注释 Corner radius 部分，它看起来像这样:

所以我需要一个建议。

Answer 1

根据我的观察，我认为这一定是您的 CAShapeLayer 路径错误的问题，因此圆圈被遮蔽了。

刚刚写了一个雷达动画，希望对你有帮助。

    let scaleAnimation = CABasicAnimation(keyPath: "transform.scale")
    scaleAnimation.fromValue = 0
    scaleAnimation.toValue = 1

    let alphaAnimation = CABasicAnimation(keyPath: "opacity")
    alphaAnimation.fromValue = 1
    alphaAnimation.toValue = 0

    let animations = CAAnimationGroup()
    animations.duration = 0.8
    animations.repeatCount = Float.infinity
    animations.timingFunction = CAMediaTimingFunction(name: kCAMediaTimingFunctionEaseOut)
    animations.animations = [scaleAnimation, alphaAnimation]

    circleView.layer.add(animations, forKey: "animations")

我所做的是，我使用了两个 CAShapeLayer(一个是橙色标记，另一个是标记背面的雷达层)。动画应用于雷达层。

    radarLayer = CAShapeLayer()
    radarLayer.frame = CGRect(x: 0, y: 0, width: self.frame.size.width, height: self.frame.size.height);
    radarLayer.path = UIBezierPath(rect: radarLayer.frame).cgPath
    radarLayer.fillColor = UIColor.orange.cgColor
    radarLayer.position = CGPoint(x: self.frame.size.width/2, y: self.frame.size.height/2)
    radarLayer.cornerRadius = radarLayer.frame.size.width/2
    radarLayer.masksToBounds = true
    radarLayer.opacity = 0
    self.layer.addSublayer(radarLayer)

    circleLayer = CAShapeLayer()
    circleLayer.frame = CGRect(x: 0, y: 0, width: 16, height: 16);
    circleLayer.path = UIBezierPath(rect: circleLayer.frame).cgPath
    circleLayer.fillColor = UIColor.orange.cgColor
    circleLayer.position = CGPoint(x: self.frame.size.width/2, y: self.frame.size.height/2)
    circleLayer.cornerRadius = circleLayer.frame.size.width/2
    circleLayer.masksToBounds = true
    self.layer.addSublayer(circleLayer)

附言。我是 Swift 的新手，如果我哪里错了，请启发我 :)

示例:http://i.imgur.com/v2jFWgw.jpg