How to blur an existing image in a UIImageView with Swift?

Question

The setup is simple.

• A ViewController with UIImageView that has an image assigned.
• A UIButton that when clicked blurs the image in the UIImageView.<

Answer 1

You could simply use UIVisualEffect to achieve blur effect. As you trying to achieve a blur effect using CoreImage.Try below code after import CoreImage to your class.

var context = CIContext(options: nil)

func blurEffect() {

    let currentFilter = CIFilter(name: "CIGaussianBlur") 
    let beginImage = CIImage(image: bg.image!)
    currentFilter!.setValue(beginImage, forKey: kCIInputImageKey)
    currentFilter!.setValue(10, forKey: kCIInputRadiusKey)

    let cropFilter = CIFilter(name: "CICrop")
    cropFilter!.setValue(currentFilter!.outputImage, forKey: kCIInputImageKey)
    cropFilter!.setValue(CIVector(cgRect: beginImage!.extent), forKey: "inputRectangle")

    let output = cropFilter!.outputImage 
    let cgimg = context.createCGImage(output!, from: output!.extent)
    let processedImage = UIImage(cgImage: cgimg!)
    bg.image = processedImage
}

Output:

Note: I recommend you to test the code in real device as Simulator performance is too slow on coreImage.