如何屏蔽和添加阴影到 UIView

Question

我正在制作一个自定义视图，我想屏蔽它并为其添加阴影。

屏蔽：

    let p = UIBezierPath()
    p.moveToPoint(CGPointMake(20, 20))
    p.addLineToPoint(CGPointMake(100, 20))
    p.addLineToPoint(CGPointMake(100, 50))
    p.addLineToPoint(CGPointMake(110, 55))
    p.addLineToPoint(CGPointMake(100, 60))
    p.addLineToPoint(CGPointMake(100, 100))
    p.addLineToPoint(CGPointMake(20, 100))
    p.closePath()

    let s = CAShapeLayer()
    s.frame = layer.bounds
    s.path = p.CGPath
    s.fillColor = UIColor.greenColor().CGColor
    layer.mask = s

蒙版有效，现在我想添加阴影。但它不起作用。

我试着给主层添加阴影，但没有任何反应。

    layer.shadowColor = UIColor.yellowColor().CGColor
    layer.shadowRadius = 10
    layer.shadowOpacity = 0.9
    layer.shadowOffset = CGSizeZero

我尝试将它添加到遮罩层，但主视图被阴影遮住了。

    s.shadowColor = UIColor.yellowColor().CGColor
    s.shadowRadius = 10
    s.shadowOpacity = 0.9
    s.shadowOffset = CGSizeZero

有什么关于如何将这个黄色阴影添加到蒙版视图的建议吗？

谢谢

Answer 1

感谢@WilsonXJ 我将蒙版更改为 addSubLayer。

这是对我有用的答案：

    let p = UIBezierPath()
    p.moveToPoint(CGPointMake(20, 20))
    p.addLineToPoint(CGPointMake(100, 20))
    p.addLineToPoint(CGPointMake(100, 50))
    p.addLineToPoint(CGPointMake(110, 55))
    p.addLineToPoint(CGPointMake(100, 60))
    p.addLineToPoint(CGPointMake(100, 100))
    p.addLineToPoint(CGPointMake(20, 100))
    p.closePath()

    let s = CAShapeLayer()
    s.fillColor = UIColor.whiteColor().CGColor
    s.frame = layer.bounds
    s.path = p.CGPath

    layer.backgroundColor = UIColor.clearColor().CGColor
    layer.addSublayer(s)

    layer.masksToBounds = true
    layer.shadowColor = UIColor.yellowColor().CGColor
    layer.shadowOffset = CGSizeZero
    layer.shadowOpacity = 0.9
    layer.shadowPath = p.CGPath
    layer.shadowRadius = 10

Answer 2

我不认为当前答案是正确的，因为没有 layer.mask 用法了。

如果您需要使用 layer.mask 并删除遮罩层的阴影 - 显而易见的解决方案是在遮罩层下方添加另一个与 layer.mask 具有相同形状的图层并将其删除阴影

示例：

let view = UIView(frame: CGRect(origin: .zero, size: CGSize(width: 500, height: 500)))
view.backgroundColor = .white
PlaygroundPage.current.liveView = view

let path: CGPath = ...

let maskedView = UIView(frame: path.boundingBox)
maskedView.center = view.center
maskedView.backgroundColor = .green
view.addSubview(maskedView)

let maskLayer = CAShapeLayer()
maskLayer.frame = maskedView.bounds
maskLayer.path = path
maskedView.layer.mask = maskLayer

let shadowLayer = CAShapeLayer()
shadowLayer.path = path
shadowLayer.frame = maskedView.frame

shadowLayer.shadowOpacity = 0.4
shadowLayer.shadowRadius = 2
shadowLayer.shadowColor = UIColor.black.cgColor
shadowLayer.shadowOffset = CGSize(width: 4, height: 4)

maskedView.superview!.layer.insertSublayer(shadowLayer, below: maskedView.layer)

Answer 3

如果你不想让你的子视图被图层覆盖，替换：

        layer.addSublayer(s)

来自

        for subview in subviews {
            layer.insertSublayer(s, below: subview.layer)
        }

如何屏蔽和添加阴影到 UIView

How to mask and add shadow to a UIView

ios

swift

uiview

calayer

cashapelayer