在UIImageView中创建一个圆孔

Question

我正在使用此代码在UIImageVIew中创建一个圆孔

 let r = imageView.bounds
    let r2 = CGRect(x: (mainScroll.contentOffset.x + 30), y:(mainScroll.contentOffset.y + UIScreen.main.bounds.height - radius + 30), width: radius - 60, height: radius - 60)
    UIGraphicsBeginImageContextWithOptions(r.size,false, 0)
    let c = UIGraphicsGetCurrentContext()
    c?.addRect(r2)
    c?.addRect(r)
    c?.clip()


    c?.setFillColor(red: red, green: green, blue: blue, alpha: 0.5)
    c?.fill(r2)
    let imagefinal1 = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return imagefinal1!

“我的问题”可能会得到剪切的图像，因为此代码会产生一个孔。