Get visible part of UIImageView as UIImage in Swift

Question

In my app, I'm trying to implement a crop feature. So now I need to convert UIImageView's visible part to UIImage. Here's a screenshot from the UI debugger.

I've tried to achieve it with this function, but it doesn't work.

func imageFromImageView(imageView: UIImageView)  -> UIImage? {
   UIGraphicsBeginImageContext(imageView.frame.size)
    let context = UIGraphicsGetCurrentContext()!
    context.rotate(by: 2 * .pi)
    
    imageView.layer.render(in: context)
    
    let image = UIGraphicsGetImageFromCurrentImageContext()
    return image
}

What are your "ImageView" settings for "setClipsToBounds " and " contentMode" ? — Umair Ahmed, Oct 11 '21 at 11:51
imageView.ClipsToBounds = true, contentMode = .scaleAspectFill — Sam, Oct 11 '21 at 12:00
@PtitXav Yep, I was assuming it. I've found that code here https://stackoverflow.com/questions/11120814/ios-get-visible-portion-of-image-for-an-uiimageview . — Sam, Oct 11 '21 at 12:33
try the code from here https://stackoverflow.com/a/41288197/7214847 — Tad, Oct 11 '21 at 12:40
So what is the result for the current code you have? Does it return the image for entire imageView? — SamB, Oct 11 '21 at 13:07
How do you define the area to be cropped? Do you have some sort of a crop rectangle? — SamB, Oct 11 '21 at 13:46
May be outdated but it can explain you : [crip uiimageview to uiimage](https://stackoverflow.com/questions/43720720/how-to-crop-a-uiimageview-to-a-new-uiimage-in-aspect-fill-mode) — Ptit Xav, Oct 11 '21 at 14:18

score 1 · Answer 1 · answered Oct 11 '21 at 13:14

You can use bellow extension:

private var rendererKey: UInt8 = 0
extension UIView {
    var renderer: UIGraphicsImageRenderer! {
         get {
             guard let rendererInstance = objc_getAssociatedObject(self, &rendererKey) as? UIGraphicsImageRenderer else {
                self.renderer = UIGraphicsImageRenderer(bounds: bounds)
                return self.renderer
             }
             return rendererInstance
        }
        set(newValue) {
            objc_setAssociatedObject(self, &rendererKey, newValue, objc_AssociationPolicy.OBJC_ASSOCIATION_RETAIN)
        }
    }
    func snapImageView() -> UIImageView {
        let img:UIImage = renderer.image { ctx in
         DispatchQueue.main.async { 
              layer.render(in: ctx.cgContext)
          }
        }
        let imageView:UIImageView = UIImageView(image: img)
        imageView.frame = renderer.format.bounds
        imageView.clipsToBounds = true
        return imageView
    }
}
// Generate image and image view of any view instance
let anImageView = yourView.snapImageView()

Yep. I've done it, but when I'm trying to upload that imageView's image property to my backend, it is showing an empty photo. — Sam, Oct 11 '21 at 13:25

Get visible part of UIImageView as UIImage in Swift

1 Answers1