How to set corner radius of imageView?

Question

In Objective-C such line

self.mainImageView.layer.cornerRadius = CGRectGetWidth(self.mainImageView.frame)/4.0f;

does its job, I tried it in Swift using analogy

self.mainImageView.layer.cornerRadius = CGRectGetWidth(self.mainImageView.frame)/4.0

and it doesn't change anything, the corners are the same as before. Moreover, Xcode does not show any syntax errors. Does Swift support any other way to reach this goal? I checked some other threads here and usually it's getting done in Swift in the way showed above.

Answer 1

Marked with @IBInspectable in swift (or IBInspectable in Objective-C), they are easily editable in Interface Builder’s attributes inspector panel.
You can directly set borderWidth,cornerRadius,borderColor in attributes inspector

extension UIView {

  @IBInspectable var cornerRadius: CGFloat {

   get{
        return layer.cornerRadius
    }
    set {
        layer.cornerRadius = newValue
        layer.masksToBounds = newValue > 0
    }
  }

  @IBInspectable var borderWidth: CGFloat {
    get {
        return layer.borderWidth
    }
    set {
        layer.borderWidth = newValue
    }
  }

  @IBInspectable var borderColor: UIColor? {
    get {
        return UIColor(cgColor: layer.borderColor!)
    }
    set {
        layer.borderColor = borderColor?.cgColor
    }
  }
}

Answer 2

Swift 3, Xcode 8, iOS 10

DispatchQueue.main.async {
  self.mainImageView.layer.cornerRadius = self.mainImageView.bounds.size.width / 2.0
  self.mainImageView.clipsToBounds = true
}

Answer 3

try this

self.mainImageView.layer.cornerRadius = CGRectGetWidth(self.mainImageView.frame)/4.0
self.mainImageView.clipsToBounds = true