IBInspectable UIView Extensions for Fun and Profit

ViewUtilities.swift

extension UIView {
  @IBInspectable var borderColor: UIColor? {
    get { return layer.borderColor.map(UIColor.init) }
    set { layer.borderColor = newValue?.CGColor }
  }
  @IBInspectable var borderWidth: CGFloat {
    get { return layer.borderWidth }
    set { layer.borderWidth = newValue }
  }
  
  @IBInspectable var cornerRadius: CGFloat {
    get { return layer.cornerRadius }
    set { layer.cornerRadius = newValue }
  }
  
  // Proof of concept, not tested
  @IBInspectable var backgroundImage: UIImage! {
    get { return nil }  // maybe use associated objects, you can't add properties in extensions
    set {
      let imageView = UIImageView(image: newValue)
      imageView.frame = bounds
      addSubview(imageView)
    }
  }
}

In Swift 4:

extension UIView {
    @IBInspectable var borderColor: UIColor? {
        get { return layer.borderColor.map(UIColor.init) }
        set { layer.borderColor = newValue?.cgColor }
    }
    @IBInspectable var borderWidth: CGFloat {
        get { return layer.borderWidth }
        set { layer.borderWidth = newValue }
    }
    
    @IBInspectable var cornerRadius: CGFloat {
        get { return layer.cornerRadius }
        set { layer.cornerRadius = newValue }
    }
    
    // Proof of concept, not tested
    @IBInspectable var backgroundImage: UIImage! {
        get { return nil }  // maybe use associated objects, you can't add properties in extensions
        set {
            let imageView = UIImageView(image: newValue)
            imageView.frame = bounds
            addSubview(imageView)
        }
    }
}