UIImage to URL with swift - ios

Question

I have an UIImage generated from a CanvasView.
I want to use the featureprintObservationForImage feature on it. However it seems to take a URL and I am trying to provide a UIImage, how can I get around this?
Here is my code:
//getting image
UIGraphicsBeginImageContextWithOptions(theCanvasView.bounds.size, false, UIScreen.main.scale)
theCanvasView.drawHierarchy(in: theCanvasView.bounds, afterScreenUpdates: true)
let image2 = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
//setting up observation for image
let drawing = featureprintObservationForImage(atURL: Bundle.main.url(image2)!)
I am getting the error on the last line that says:
Cannot convert value of type 'UIImage?' to expected argument type
'String'
Any ideas?

Answer 1

Assuming that you need to get a VNFeaturePrintObservation instance, you could request an image instead of a URL by using the VNImageRequestHandler.
Assuming that featureprintObservationForImage method is (or looks something like this):
func featureprintObservationForImage(atURL url: URL) -> VNFeaturePrintObservation? {
let requestHandler = VNImageRequestHandler(url: url, options: [:])
let request = VNGenerateImageFeaturePrintRequest()
do {
try requestHandler.perform([request])
return request.results?.first as? VNFeaturePrintObservation
} catch {
print("Vision error: \(error)")
return nil
}
}
You could have a different version as:
func featureprintObservationForImage(_ image: CIImage?) -> VNFeaturePrintObservation? {
guard let ciImage = image else {
return nil
}
let requestHandler = VNImageRequestHandler(ciImage: ciImage, options: [:])
let request = VNGenerateImageFeaturePrintRequest()
do {
try requestHandler.perform([request])
return request.results?.first as? VNFeaturePrintObservation
} catch {
print("Vision error: \(error)")
return nil
}
}
The differences in the second one are:
The signature of the method, takes an optional CIImage instead of a URL.
The initializer of the requestHandler.
Therefore:
let drawing = featureprintObservationForImage(image2?.ciImage)