iOS UILabel文字加上阴影效果

// 店名
let leftNavShop: UILabel = {
    let label = UILabel()
    label.text = "xxx"
    label.textColor = UIColor.white
    label.font = UIFont.adjustBoldFontSize(ofSize: 15)
    label.shadowColor = UIColor.black.withAlphaComponent(0.3)
    label.shadowOffset = CGSize(width: 2, height: 2)
    return label
}()
// 阴影的颜色
label.shadowColor =  UIColor.black.withAlphaComponent(0.3)
// 阴影的偏移
label.shadowOffset = CGSize(width: 2, height: 2)
width: 正 -> 右，负 -> 左
height：正 -> 下，负 -> 上
#这里的width、height代表的是x、y值。

方法二

// 设置阴影
func setShadow(color:UIColor, offset:CGSize, opacity:Float, radius:CGFloat) {
    //设置阴影颜色
    self.layer.shadowColor   = color.cgColor
    //设置阴影偏移量
    self.layer.shadowOffset  = offset
    //设置透明度
    self.layer.shadowOpacity = opacity
    //设置阴影半径
    self.layer.shadowRadius  = radius
 }