title: Getting error [UIImage extent]: unrecognized selector sent to instance
body: <p>I'm trying to apply a radial blur to my UIImageView but when I try this I get the error</p>
  
  <blockquote>
    <p>[UIImage extent]: unrecognized selector sent to instance</p>
  </blockquote>
  
  <p>The code I'm using is from the example on:
  <a href="https://developer.apple.com/documentation/coreimage/selectively_focusing_on_an_image" rel="noreferrer">https://developer.apple.com/documentation/coreimage/selectively_focusing_on_an_image</a></p>
  
  <pre><code>let h = bgImage.image!.size.height
  let w = bgImage.image!.size.width
  guard let radialMask = CIFilter(name:"CIRadialGradient") else {
      return
  }
  let imageCenter = CIVector(x:0.55 * w, y:0.6 * h)
  radialMask.setValue(imageCenter, forKey:kCIInputCenterKey)
  radialMask.setValue(0.2 * h, forKey:"inputRadius0")
  radialMask.setValue(0.3 * h, forKey:"inputRadius1")
  radialMask.setValue(CIColor(red:0, green:1, blue:0, alpha:0),
                      forKey:"inputColor0")
  radialMask.setValue(CIColor(red:0, green:1, blue:0, alpha:1),
                      forKey:"inputColor1")
  
  guard let maskedVariableBlur = CIFilter(name:"CIMaskedVariableBlur") else {
      return
  }
  maskedVariableBlur.setValue(bgImage.image, forKey: kCIInputImageKey)
  maskedVariableBlur.setValue(10, forKey: kCIInputRadiusKey)
  maskedVariableBlur.setValue(radialMask.outputImage, forKey: "inputMask")
  let selectivelyFocusedCIImage = maskedVariableBlur.outputImage/
  </code></pre>
  
  <p>In which <code>bgImage</code> is a <code>UIImageView</code></p>
  
  <p>What am I doing wrong here?</p>