Cut a UIImage into a circle

Question

I want to cut a UIImage into a circle so that I can then use it as an annotation. Every answer on this site that I've found describes creating an UIImageView, then modifying that and displaying it, but you cant set the image of an annotation to an UIImageView, only a UIImage. How should I go about this?

Answer 1

Xcode 11 • Swift 5.1 or later

edit/update: For iOS10+ We can use UIGraphicsImageRenderer. For older Swift syntax check edit history.

extension UIImage {     var isPortrait:  Bool    { size.height > size.width }     var isLandscape: Bool    { size.width > size.height }     var breadth:     CGFloat { min(size.width, size.height) }     var breadthSize: CGSize  { .init(width: breadth, height: breadth) }     var breadthRect: CGRect  { .init(origin: .zero, size: breadthSize) }     var circleMasked: UIImage? {         guard let cgImage = cgImage?             .cropping(to: .init(origin: .init(x: isLandscape ? ((size.width-size.height)/2).rounded(.down) : 0,                                               y: isPortrait  ? ((size.height-size.width)/2).rounded(.down) : 0),                                 size: breadthSize)) else { return nil }         let format = imageRendererFormat         format.opaque = false         return UIGraphicsImageRenderer(size: breadthSize, format: format).image { _ in             UIBezierPath(ovalIn: breadthRect).addClip()             UIImage(cgImage: cgImage, scale: format.scale, orientation: imageOrientation)             .draw(in: .init(origin: .zero, size: breadthSize))         }     } } 

Playground Testing

let profilePicture = UIImage(data: try! Data(contentsOf: URL(string:"http://i.stack.imgur.com/Xs4RX.jpg")!))! profilePicture.circleMasked 

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Answer 2

Make sure to import QuarzCore if needed.

 func maskRoundedImage(image: UIImage, radius: CGFloat) -> UIImage {         let imageView: UIImageView = UIImageView(image: image)         let layer = imageView.layer         layer.masksToBounds = true         layer.cornerRadius = radius         UIGraphicsBeginImageContext(imageView.bounds.size)         layer.render(in: UIGraphicsGetCurrentContext()!)         let roundedImage = UIGraphicsGetImageFromCurrentImageContext()         UIGraphicsEndImageContext()         return roundedImage!     }