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

You can use this code to circle Image

extension UIImage {
func circleImage(_ cornerRadius: CGFloat, size: CGSize) -> UIImage? {
    let rect = CGRect(x: 0, y: 0, width: size.width, height: size.height)
    UIGraphicsBeginImageContextWithOptions(size, false, 0)
    if let context = UIGraphicsGetCurrentContext() {
        var path: UIBezierPath
        if size.height == size.width {
            if cornerRadius == size.width/2 {
                path = UIBezierPath(arcCenter: CGPoint(x: size.width/2, y: size.height/2), radius: cornerRadius, startAngle: 0, endAngle: 2.0*CGFloat(Double.pi), clockwise: true)
            }else {
                path = UIBezierPath(roundedRect: rect, cornerRadius: cornerRadius)
            }
        }else {
            path = UIBezierPath(roundedRect: rect, cornerRadius: cornerRadius)
        }
        context.addPath(path.cgPath)
        context.clip()
        self.draw(in: rect)
        // 从上下文上获取剪裁后的照片
        guard let uncompressedImage = UIGraphicsGetImageFromCurrentImageContext() else {
            UIGraphicsEndImageContext()
            return nil
        }
        // 关闭上下文
        UIGraphicsEndImageContext()
        return uncompressedImage
    }else {
        return nil
    }
}}

Answer 2

Based on Nikos answer:

public extension UIImage {

func roundedImage() -> UIImage {
    let imageView: UIImageView = UIImageView(image: self)
    let layer = imageView.layer
    layer.masksToBounds = true
    layer.cornerRadius = imageView.frame.width / 2
    UIGraphicsBeginImageContext(imageView.bounds.size)
    layer.render(in: UIGraphicsGetCurrentContext()!)
    let roundedImage = UIGraphicsGetImageFromCurrentImageContext()
    UIGraphicsEndImageContext()
    return roundedImage!
    }

}

//Usage

let roundedImage = image.roundedImage()

Answer 3

Xcode 8.1, Swift 3.0.1

My code will look like this:

let image = yourImage.resize(CGSize(width: 20, height: 20))?.circled(forRadius: 20)

Add UIImage Extension, then:

func resize(_ size: CGSize) -> UIImage? {
    let rect = CGRect(origin: .zero, size: size)
    return redraw(in: rect)
}

func redraw(in rect: CGRect) -> UIImage? {
    UIGraphicsBeginImageContextWithOptions(rect.size, false, UIScreen.main.scale)

    guard let context = UIGraphicsGetCurrentContext(), let cgImage = cgImage else { return nil }

    let rect = CGRect(origin: .zero, size: size)
    let flipVertical = CGAffineTransform(a: 1, b: 0, c: 0, d: -1, tx: 0, ty: rect.size.height)

    context.concatenate(flipVertical)
    context.draw(cgImage, in: rect)

    let image = UIGraphicsGetImageFromCurrentImageContext()
    UIGraphicsEndImageContext()
    return image
}

func circled(forRadius radius: CGFloat) -> UIImage? {
    let rediusSize = CGSize(width: radius, height: radius)
    let rect = CGRect(origin: .zero, size: size)

    UIGraphicsBeginImageContextWithOptions(size, false, UIScreen.main.scale)

    guard let context = UIGraphicsGetCurrentContext(), let cgImage = cgImage else { return nil }

    let flipVertical = CGAffineTransform(a: 1, b: 0, c: 0, d: -1, tx: 0, ty: rect.size.height)
    context.concatenate(flipVertical)

    let bezierPath = UIBezierPath(roundedRect: rect, byRoundingCorners: [.allCorners], cornerRadii: rediusSize)
    context.addPath(bezierPath.cgPath)
    context.clip()

    context.drawPath(using: .fillStroke)
    context.draw(cgImage, in: rect)

    let image = UIGraphicsGetImageFromCurrentImageContext()
    UIGraphicsEndImageContext()

    return image
}

Answer 4

swift 3 conform to MVC pattern create an external file

@IBDesignable
class RoundImage: UIImageView{


@IBInspectable var cornerRadius: CGFloat = 0 {
    didSet{
        self.layer.cornerRadius = cornerRadius
    }
}

// set border width
@IBInspectable var borderWidth: CGFloat = 0 {
    didSet{
        self.layer.borderWidth = borderWidth
    }
}

// set border color

@IBInspectable var borderColor: UIColor = UIColor.clear {
    didSet{
        self.layer.borderColor = borderColor.cgColor
    }
}

override func awakeFromNib() {
    self.clipsToBounds = true
}


}// class

call class in the IB on storyboard

set cornerradius as you please (1/2 of width if desire circle)

Done!

Answer 5

All these answers were really complex for a straight forward solution. I just replicated my Objective-C code and adjusted for Swift.

self.myImageView?.layer.cornerRadius = (self.myImageView?.frame.size.width)! / 2;
self.myImageView?.clipsToBounds = true