Is it possible to use UIKit extensions in SwiftUI? - ios

Question

I have a nice UIImage extension that renders circular images in high quality using less memory. I want to either use this extension or re-create it in SwiftUI so I can use it. The problem is I am very new to SwiftUI and am not sure if it is even possible. Is there a way to use this?
Here's the extension:
extension UIImage {
class func circularImage(from image: UIImage, size: CGSize) -> UIImage? {
let scale = UIScreen.main.scale
let circleRect = CGRect(x: 0, y: 0, width: size.width * scale, height: size.height * scale)
UIGraphicsBeginImageContextWithOptions(circleRect.size, false, scale)
let circlePath = UIBezierPath(roundedRect: circleRect, cornerRadius: circleRect.size.width/2.0)
circlePath.addClip()
image.draw(in: circleRect)
if let roundImage = UIGraphicsGetImageFromCurrentImageContext() {
return roundImage
}
return nil
}
}

Answer 1

You can create your UIImage like normal.
Then, just convert this to a SwiftUI image with:
Image(uiImage: image)
Do not initialize your UIImage in the view body or initializer, as this can be quite expensive - instead do it on appear with onAppear(perform:).
Example:
struct ContentView: View {
#State private var circularImage: UIImage?
var body: some View {
VStack {
Text("Hello world!")
if let circularImage = circularImage {
Image(uiImage: circularImage)
}
}
.onAppear {
guard let image: UIImage = UIImage(named: "background") else { return }
circularImage = UIImage.circularImage(from: image, size: CGSize(width: 100, height: 100))
}
}
}