How to set UIImageView with rounded corners for aspect fit mode

Question

I usually use the following code to set rounded corners.

imageView.layer.cornerRadius = 10

It works when the imageView is set at Aspect Fill.

But when the imageView is set to Aspect Fit mode, and the ratio between imageView and picture are different. The rounded corners effect won't be able to tell.

The background color is set to green for showing the rounded corners.

Is there any way to set 'real image part' to rounded corners.

Thank you in advance for your answers.

Answer 1

Use this extension to UIImageView:

extension UIImageView
{
    func roundCornersForAspectFit(radius: CGFloat)
    {
        if let image = self.image {

            //calculate drawingRect
            let boundsScale = self.bounds.size.width / self.bounds.size.height
            let imageScale = image.size.width / image.size.height

            var drawingRect: CGRect = self.bounds

            if boundsScale > imageScale {
                drawingRect.size.width =  drawingRect.size.height * imageScale
                drawingRect.origin.x = (self.bounds.size.width - drawingRect.size.width) / 2
            } else {
                drawingRect.size.height = drawingRect.size.width / imageScale
                drawingRect.origin.y = (self.bounds.size.height - drawingRect.size.height) / 2
            }
            let path = UIBezierPath(roundedRect: drawingRect, cornerRadius: radius)
            let mask = CAShapeLayer()
            mask.path = path.cgPath
            self.layer.mask = mask
        }
    }
}

Answer 2

Swift 3 version of the helpful, accepted answer is over here!

extension UIImageView {
func roundCornersForAspectFit(radius: CGFloat)
{
    if let image = self.image {

        //calculate drawingRect
        let boundsScale = self.bounds.size.width / self.bounds.size.height
        let imageScale = image.size.width / image.size.height

        var drawingRect : CGRect = self.bounds

        if boundsScale > imageScale {
            drawingRect.size.width =  drawingRect.size.height * imageScale
            drawingRect.origin.x = (self.bounds.size.width - drawingRect.size.width) / 2
        }else {
            drawingRect.size.height = drawingRect.size.width / imageScale
            drawingRect.origin.y = (self.bounds.size.height - drawingRect.size.height) / 2
        }
        let path = UIBezierPath(roundedRect: drawingRect, cornerRadius: radius)
        let mask = CAShapeLayer()
        mask.path = path.cgPath
        self.layer.mask = mask
        }
    }
}

Answer 3

Try this may help you:

import UIKit


class ViewController: UIViewController{

    @IBOutlet weak var myImageView: UIImageView!

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.

        myImageView.contentMode = UIViewContentMode.ScaleAspectFit
        myImageView.clipsToBounds = true
        //myImageView.layer.cornerRadius = 10.0
        myImageView.layer.masksToBounds = true

        let simpleImage = UIImage(named:"ipad5_einladung.jpg")
        let corneredImage = generateRoundCornerImage(simpleImage!, radius: 10)

        //Set cornered Image
        myImageView.image = corneredImage;

    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }


    func generateRoundCornerImage(image : UIImage , radius : CGFloat) -> UIImage {

        let imageLayer = CALayer()
        imageLayer.frame = CGRectMake(0, 0, image.size.width, image.size.height)
        imageLayer.contents = image.CGImage
        imageLayer.masksToBounds = true
        imageLayer.cornerRadius = radius

        UIGraphicsBeginImageContext(image.size)
        imageLayer.renderInContext(UIGraphicsGetCurrentContext())
        let roundedImage = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()

        return roundedImage
    }

}