ios - 尝试添加图层蒙版时 UIImage 消失

Question

我创建了这个函数来圆化 UIImageView 上的特定角:

func roundCorners(corners: [UIRectCorner], imageView: UIImageView) -> CAShapeLayer {
    let maskPath = UIBezierPath.init(roundedRect: imageView.bounds, byRoundingCorners:[.topLeft], cornerRadii: CGSize.init(width: 7.0, height: 7.0))
    let maskLayer = CAShapeLayer()
    maskLayer.frame = imageView.frame
    maskLayer.path = maskPath.cgPath
    return maskLayer
}

当我像这样将它应用于图像 topLeftImage 时:topLeftImage.layer.mask = roundCorners(corners: [.topLeft], imageView: topLeftImage)，它使图像消失。这是我声明图像的方式:

let topLeftImage: UIImageView = {
    let iv = UIImageView()
    iv.image = #imageLiteral(resourceName: "myImage")
    iv.layoutIfNeeded()
    iv.translatesAutoresizingMaskIntoConstraints = false
    iv.contentMode = UIViewContentMode.scaleAspectFill
    iv.layer.masksToBounds = true
    iv.clipsToBounds = true
    return iv
}()

如何在应用图层蒙版的同时让图像仍然显示在屏幕上。

Answer 1

我认为图像没有出现在屏幕上，因为您没有使用框架初始化 UIImageView。试试下面的代码片段:

let iv = UIImageView(frame: CGRect(x: 10, y: 10, width: 100, height: 100))