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
        }
    }
}