operation.swift

import UIKit

class BlurImageOperation: Operation {

    var outputImage: UIImage?

    override func main() {
        guard let imageProvider = dependencies.first as? ImageProvider,
            let providedImage = imageProvider.providedImage else { return }


        let ciImage = CIImage(image: providedImage)!
        guard let crystallize = CIFilter(name: "CICrystallize",
                                   withInputParameters: [kCIInputRadiusKey: 30,
                                                         kCIInputImageKey: ciImage])
            else { return }

        let ciContext = CIContext()
        guard let crystallizedImage = crystallize.outputImage else { return }
        let cgImage = ciContext.createCGImage(crystallizedImage,
                                              from: crystallizedImage.extent)
        outputImage = UIImage(cgImage: cgImage!)

    }
}