Use Storyboard to mask UIView and give rounded corners?

Lots of questions like this explain how to programmatically create a mask and provide rounded corners to a UIView.

Is there a way to do it all within Storyboard? Just asking because it seems like creating rounded corners in Storyboard keeps a clearer demarcation between presentation and logic.


Yes, I use that a lot but question like this was already answered many times.

But anyway in Interface Builder. You need to add User Defined Runtime Attributes like this:

layer.masksToBounds Boolean YES
layer.cornerRadius Number {View's Width/2}

and enable

Clips subviews


You can do it in a storyboard by using user-defined properties. Select the view that you want to round and open its Identity Inspector. In the User Defined Runtime Attributes section, add the following two entries:

  • Key Path: layer.cornerRadius, Type: Number, Value: (whatever radius you want)
  • Key Path: layer.masksToBounds, Type: Boolean, Value: checked

You may have to import QuartzKit in your view's corresponding class file (if any), but I swear that I've gotten it to work without doing that. Your results may vary.

EDIT: Example of a dynamic radius

extension UIView {

    /// The ratio (from 0.0 to 1.0, inclusive) of the view's corner radius
    /// to its width. For example, a 50% radius would be specified with
    /// `cornerRadiusRatio = 0.5`.
    @IBDesignable public var cornerRadiusRatio: CGFloat {
        get {
            return layer.cornerRadius / frame.width

        set {
            // Make sure that it's between 0.0 and 1.0. If not, restrict it
            // to that range.
            let normalizedRatio = max(0.0, min(1.0, newValue))
            layer.cornerRadius = frame.width * normalizedRatio


I verified that this works in a playground.

Select view

extension UIView {

    @IBInspectable var cornerRadiusV: CGFloat {
        get {
            return layer.cornerRadius
        set {
            layer.cornerRadius = newValue
            layer.masksToBounds = newValue > 0

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

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

Even after making all changes in storyboard, Woraphot's answer doesn't work for me.

This worked for me :
layer.cornerRadius = 10
layer.borderWidth = 1
layer.borderColor =

Long answer :

Rounded Corners of UIView/UIButton etc
customUIView.layer.cornerRadius = 10
Border Thickness
pcustomUIView.layer.borderWidth = 1
Border Color
customUIView.layer.borderColor =

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