Swift - 给图片和按钮添加阴影边框

最近比较忙，想要做的事情有很多，能做出来的就只有一部份，我觉得也许是我没有计划和规律造成的，我需要坚持下去，今天写了一个swift2.0给按钮或者图片添加阴影的效果，就当做笔记吧:-)

Swift Code:

let image1 = UIImageView(frame: CGRectMake(,,self.view.frame.width-,))
        image1.image = UIImage(named: "sea.jpg")
        self.view.addSubview(image1)
        //为图片添加阴影
        image1.layer.shadowOpacity = 0.8//设置阴影透明度
        image1.layer.shadowColor = UIColor.blackColor().CGColor
        image1.layer.shadowOffset = CGSize(width: , height: )//设置阴影偏移量

        let image2 = UIImageView(image: UIImage(named: "wenzi"))
        image2.frame = CGRectMake(, , self.view.frame.width-, )
        self.view.addSubview(image2)
        //为图片添加阴影（透明背景）
        image2.layer.shadowOpacity = 0.8
        image2.layer.shadowColor = UIColor.blackColor().CGColor
        image2.layer.shadowOffset = CGSize(width: , height: )
        image2.layer.shadowRadius = 

        let button = UIButton(frame: CGRectMake(, , , ))
        button.backgroundColor = UIColor(red:0.02, green:0.48, blue:, alpha:)
        //设置圆角
        button.layer.borderColor = UIColor.whiteColor().CGColor
        button.layer.borderWidth =
        button.layer.cornerRadius =
        button.setTitle("I am Abel", forState: UIControlState.Normal)//设置按钮标题
        button.setTitleColor(UIColor.whiteColor(), forState: UIControlState.Normal)//设置按钮标题颜色
        self.view.addSubview(button)
        //为按钮添加阴影
        button.layer.shadowOpacity = 0.8
        button.layer.shadowColor = UIColor.blackColor().CGColor
        button.layer.shadowOffset = CGSize(width: , height: )

运行效果：