Creates a UIViewController with Blurred Background Which acts like a UIHostingController for SwiftUI Views (Useful for UIKit developers using SwiftUI Views for Modal Views)

BlurredHostingController.swift

//
//  BluredBackgroundHostingController.swift
//  v1.0.1
//
//  Created by Ashley Chapman on 07/04/2020.
//  Copyright © 2020 Ashley Chapman. All rights reserved.
//

import UIKit

class BlurredHostingController: UIViewController {

    // Variables
    var hostingController: UIViewController!
    var blurEffect: UIBlurEffect.Style = .prominent
    var translucentEffect: TranslucentEffect = .regular
    
    override func viewDidLoad() {
        super.viewDidLoad()

        // Do any additional setup after loading the view.
        self.view.backgroundColor = nil
        
        if (translucentEffect != .opaque) {
            let blurEffect = UIBlurEffect(style: self.blurEffect)
            let blurEffectView = UIVisualEffectView(effect: blurEffect)
            blurEffectView.frame = self.view.frame
            
            self.view.addSubview(blurEffectView)
            
            NSLayoutConstraint.activate([
                blurEffectView.widthAnchor.constraint(equalTo: view.widthAnchor),
                blurEffectView.heightAnchor.constraint(equalTo: view.heightAnchor),
                blurEffectView.centerXAnchor.constraint(equalTo: view.centerXAnchor),
                blurEffectView.centerYAnchor.constraint(equalTo: view.centerYAnchor)
            ])
        }
        
        self.addChild(hostingController)
        hostingController.view.translatesAutoresizingMaskIntoConstraints = false
        hostingController.view.alpha = translucent()
        hostingController.view.backgroundColor = nil
        
        self.view.addSubview(hostingController.view)
        hostingController.didMove(toParent: self)
        
        NSLayoutConstraint.activate([
            hostingController.view.widthAnchor.constraint(equalTo: view.widthAnchor),
            hostingController.view.heightAnchor.constraint(equalTo: view.heightAnchor),
            hostingController.view.centerXAnchor.constraint(equalTo: view.centerXAnchor),
            hostingController.view.centerYAnchor.constraint(equalTo: view.centerYAnchor)
        ])
    }
    
    private func translucent() -> CGFloat {
        if (translucentEffect == .opaque) {
            return 1.0
        } else if (translucentEffect == .ultrathick) {
            return 0.95
        } else if (translucentEffect == .thick) {
            return 0.9
        } else if (translucentEffect == .regular) {
            return 0.85
        } else if (translucentEffect == .prominent) {
            return 0.8
        } else if (translucentEffect == .thin) {
            return 0.75
        } else if (translucentEffect == .ultrathin) {
            return 0.7
        } else {
            return 1.0
        }
    }
}

enum TranslucentEffect {
    case opaque
    case ultrathick
    case thick
    case regular
    case prominent
    case thin
    case ultrathin
}