7
问题
我正在创建一个爆炸环效果。我使用多个CAShapeLayer
并为每个图层创建一个UIBezierPath
。当视图初始化时,所有图层都有一个宽度为0
的路径。当一个动作被触发时,这些环动画到一个更大的路径。在两个圆形UIBezierPath之间进行动画时出现奇怪行为
如下面的演示所示,每个图层的右侧边缘比每个圆形图层的其余部分的动画更慢。
演示
代码
绘制层:
func draw(inView view: UIView) -> CAShapeLayer {
let shapeLayer = CAShapeLayer()
// size.width defaults to 0
let circlePath = UIBezierPath(arcCenter: view.center, radius: size.width/2, startAngle: 0, endAngle: CGFloat(360.0).toRadians(), clockwise: true)
shapeLayer.path = circlePath.CGPath
shapeLayer.frame = view.frame
return shapeLayer
}
更新层
func updateAnimated(updatedOpacity: CGFloat, updatedSize: CGSize, duration: CGFloat) {
let updatePath = UIBezierPath(arcCenter: view.center, radius: updatedSize.width/2,
startAngle: 0, endAngle: CGFloat(360).toRadians(), clockwise: true)
let pathAnimation = CABasicAnimation(keyPath: "path")
pathAnimation.fromValue = layer.path // the current path (initially with width 0)
pathAnimation.toValue = updatePath.CGPath
let opacityAnimation = CABasicAnimation(keyPath: "opacity")
opacityAnimation.fromValue = self.opacity
opacityAnimation.toValue = updatedOpacity
let animationGroup = CAAnimationGroup()
animationGroup.animations = [pathAnimation, opacityAnimation]
animationGroup.duration = Double(duration)
animationGroup.fillMode = kCAFillModeForwards
animationGroup.removedOnCompletion = false
layer.addAnimation(animationGroup, forKey: "shape_update")
... update variables ...
}
将宽度的初始值设置为1而不是0似乎解决了它,感谢您的帮助! – Ollie