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 UIImage

Answer 1

UIImage extension:

extension UIImage {

    func circularImage(size size: CGSize?) -> UIImage {
        let newSize = size ?? self.size

        let minEdge = min(newSize.height, newSize.width)
        let size = CGSize(width: minEdge, height: minEdge)

        UIGraphicsBeginImageContextWithOptions(size, false, 0.0)
        let context = UIGraphicsGetCurrentContext()

        self.drawInRect(CGRect(origin: CGPoint.zero, size: size), blendMode: .Copy, alpha: 1.0)

        CGContextSetBlendMode(context, .Copy)
        CGContextSetFillColorWithColor(context, UIColor.clearColor().CGColor)

        let rectPath = UIBezierPath(rect: CGRect(origin: CGPoint.zero, size: size))
        let circlePath = UIBezierPath(ovalInRect: CGRect(origin: CGPoint.zero, size: size))
        rectPath.appendPath(circlePath)
        rectPath.usesEvenOddFillRule = true
        rectPath.fill()

        let result = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()

        return result
    }

}

Usage:

UIImageView:

@IBDesignable class CircularImageView: UIImageView {

    override var image: UIImage? {
        didSet {
            super.image = image?.circularImage(size: nil)
        }
    }

}

UIButton:

@IBDesignable class CircularImageButton: UIButton {

    override func setImage(image: UIImage?, forState state: UIControlState) {
        let circularImage = image?.circularImage(size: nil)
        super.setImage(circularImage, forState: state)
    }

}