To make a rounded UIView, specify a cornerRadius for the view's layer.
This also applies any class which inherits from UIView, such as UIImageView.
Swift Code
someImageView.layoutIfNeeded()
someImageView.clipsToBounds = true
someImageView.layer.cornerRadius = 10
Objective-C Code
[someImageView layoutIfNeeded];
someImageView.clipsToBounds = YES;
someImageView.layer.cornerRadius = 10;
Example
//Swift code
topImageView.layoutIfNeeded()
bottomImageView.layoutIfNeeded()
topImageView.clipsToBounds = true
topImageView.layer.cornerRadius = 10
bottomImageView.clipsToBounds = true
bottomImageView.layer.cornerRadius = bottomImageView.frame.width / 2
//Objective-C code
[topImageView layoutIfNeeded]
[bottomImageView layoutIfNeeded];
topImageView.clipsToBounds = YES;
topImageView.layer.cornerRadius = 10;
bottomImageView.clipsToBounds = YES;
bottomImageView.cornerRadius = CGRectGetWidth(bottomImageView.frame) / 2;
Here is the result, showing the rounded view effect using the specified corner radius:

Note
To do this you need to include the QuartzCore framework.
#import <QuartzCore/QuartzCore.h>
A rounded view effect can also be achieved non-programmatically by setting the corresponding properties in Storyboard.
Since layer properties aren't exposed in Storyboard, you have to modify the cornerRadius attribute via the User Defined Runtime Attributes section.
You can use this handy extension to apply rounded view as long as it has same width and height.
extension UIView {
@discardableResult
public func setAsCircle() -> Self {
self.clipsToBounds = true
let frameSize = self.frame.size
self.layer.cornerRadius = min(frameSize.width, frameSize.height) / 2.0
return self
}
}
To use it:
yourView.setAsCircle()