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边界层动画不从中心缩放

calayer core-animation animation ios

Sohil R. Memon · 技术社区 · 6 年前

我正在努力解决这个奇怪的问题,比如当我向任何层添加缩放变换时,它都不是从中心开始动画的。它是从起源开始的。

func addSquareBorderLayer() {

    borderLayer = CAShapeLayer()
    let rect = CGRect(x: spotlight!.frame.origin.x, y: spotlight!.frame.origin.y, width: spotlight!.frame.width, height: spotlight!.frame.height)
    borderLayer?.path = UIBezierPath(roundedRect: rect, cornerRadius: spotlight!.cornerRadius).cgPath
    borderLayer?.strokeColor = UIColor(red: 91/255, green: 186/255, blue: 162/255, alpha: 1).cgColor //ColorRGB(91, 186, 162)
    borderLayer?.lineWidth = spotlight!.cornerRadius
    borderLayer?.fillColor = UIColor.clear.cgColor
    layer.addSublayer(borderLayer!)

    animatePulsatingLayer(pulsatingLayer: layer)
}

private func animatePulsatingLayer(pulsatingLayer : CALayer) {
    let animation = CABasicAnimation(keyPath: "transform.scale")
    animation.duration       = 0.5
    animation.repeatCount    = .greatestFiniteMagnitude
    animation.autoreverses   = true
    animation.fromValue      = 1
    animation.toValue        = 1.05
    pulsatingLayer.add(animation, forKey: "pulsing")
}

参考正在发生的事情: https://www.dropbox.com/s/0hqdrrv310du7vz/mo.mov?dl=0

1 回复 | 直到 6 年前

Kamran 6 年前

有点棘手。你需要设置 frame 对于作为 rect 您当前正在为 path origin 使圆(或任何形状)绘制在与帧原点相同的位置。这将允许动画应用于 anchorPoint

下面是完整的例子,

var borderLayer: CAShapeLayer!

func addSquareBorderLayer() {

    let size: CGFloat = 100

    borderLayer = CAShapeLayer()
    let rect = CGRect(origin: .zero, size: CGSize(width: size, height: size))
    borderLayer?.path = UIBezierPath(roundedRect: rect, cornerRadius: 50).cgPath
    borderLayer?.strokeColor = UIColor(red: 91/255, green: 186/255, blue: 162/255, alpha: 1).cgColor
    borderLayer?.lineWidth = 20
    borderLayer?.fillColor = UIColor.clear.cgColor
    borderLayer?.frame = CGRect(origin: CGPoint(x: 100, y: 200), size: rect.size)
    self.view.layer.addSublayer(borderLayer!)

    animatePulsatingLayer(pulsatingLayer: borderLayer!)
}

private func animatePulsatingLayer(pulsatingLayer : CALayer) {
    let animation = CABasicAnimation(keyPath: "transform.scale")
    animation.duration       = 0.3
    animation.repeatCount    = .greatestFiniteMagnitude
    animation.autoreverses   = true
    animation.fromValue      = 1
    animation.toValue        = 1.2
    pulsatingLayer.add(animation, forKey: "pulsing")
}

结果