UIView to UIImage code is not working. It causing an runtime error - swift

Question

I have to convert UIView to UIImage because I want to make a custom marker.
Currently, I'm making an app using Naver Map SDK.
Here is My Code.
let marker = NMFMarker()
marker.position = NMGLatLng(lat: lat, lng: lng)
let windowView = CustomInfoWindowView()
windowView.nameLabel.text = name
windowView.jobLabel.text = job
windowView.scoreLabel.text = "\(score)"
marker.iconImage = NMFOverlayImage(image: windowView.asImage())
marker.mapView = mapView
NMFOverlayImage only supported UIImage type.
Here is My full code.
class MapViewController: UIViewController {
let viewModel = MapViewModel()
let locations = BehaviorRelay<Void>(value: ())
let disposedBag = DisposeBag()
private let imageCell = UIImageView()
override func viewDidLoad() {
super.viewDidLoad()
let mapView = NMFMapView(frame: view.frame)
view.addSubview(mapView)
bind(mapView: mapView)
}
private func bind(mapView: NMFMapView) {
let input = MapViewModel.Input(getLocations: locations.asSignal(onErrorJustReturn: ()))
let output = viewModel.transform(input)
output.getLocations.asObservable().subscribe(onNext: { [unowned self] res in
if !res.isEmpty {
for i in 0..<res.count {
addMarker(
lat: res[i].address[1],
lng: res[i].address[0],
mapView: mapView,
name: res[i].name,
job: res[i].field,
score: res[i].level
)
}
}
}).disposed(by: disposedBag)
}
private func addMarker(lat: Double, lng: Double, mapView: NMFMapView, name: String, job: String, score: Double) {
let marker = NMFMarker()
marker.position = NMGLatLng(lat: lat, lng: lng)
let windowView = CustomInfoWindowView()
windowView.nameLabel.text = name
windowView.jobLabel.text = job
windowView.scoreLabel.text = "\(score)"
marker.iconImage = NMFOverlayImage(image: windowView.asImage())
marker.mapView = mapView
}
}
and this is my custom view code.
import UIKit
import SnapKit
import Then
class CustomInfoWindowView: UIView {
let customView = UIView().then {
$0.backgroundColor = .clear
}
let windowView = UIView().then {
$0.backgroundColor = R.color.mainColor()
$0.layer.cornerRadius = 10
}
let marker = UIImageView().then {
$0.image = R.image.marker()
}
let nameLabel = UILabel().then {
$0.font = .boldSystemFont(ofSize: 16)
$0.textColor = .white
}
let jobLabel = UILabel().then {
$0.font = .systemFont(ofSize: 12, weight: .medium)
$0.textColor = R.color.underLine()!
}
let starLogo = UIImageView().then {
$0.image = UIImage(systemName: "star.fill")
$0.tintColor = .systemYellow
}
let scoreLabel = UILabel().then {
$0.font = .boldSystemFont(ofSize: 14)
$0.textColor = .white
}
override init(frame: CGRect) {
super.init(frame: frame)
setUpSubViews()
}
required init?(coder: NSCoder) {
super.init(coder: coder)
}
private func setUpSubViews() {
self.addSubview(customView)
[windowView, marker].forEach({customView.addSubview($0)})
[nameLabel, jobLabel, starLogo, scoreLabel].forEach({self.addSubview($0)})
customView.snp.makeConstraints {
$0.width.equalTo(108)
$0.height.equalTo(100)
}
windowView.snp.makeConstraints {
$0.width.equalToSuperview()
$0.height.equalTo(64)
$0.top.equalTo(0)
}
marker.snp.makeConstraints {
$0.width.equalTo(20)
$0.height.equalTo(27)
$0.top.equalTo(windowView.snp.bottom).offset(10)
$0.centerX.equalTo(windowView.snp.centerX)
}
nameLabel.snp.makeConstraints {
$0.top.leading.equalTo(10)
$0.width.equalTo(10)
}
jobLabel.snp.makeConstraints {
$0.centerY.equalTo(nameLabel.snp.centerY)
$0.leading.equalTo(nameLabel.snp.trailing).offset(5)
}
starLogo.snp.makeConstraints {
$0.top.equalTo(nameLabel.snp.bottom).offset(5)
$0.leading.equalTo(nameLabel.snp.leading)
$0.width.height.equalTo(15)
}
scoreLabel.snp.makeConstraints {
$0.centerY.equalTo(starLogo.snp.centerY)
$0.leading.equalTo(starLogo.snp.trailing).offset(3)
}
}
}
and this is my UIView Extension code.
extension UIView {
func asImage() -> UIImage {
let renderer = UIGraphicsImageRenderer(bounds: bounds)
return renderer.image { context in
layer.render(in: context.cgContext)
}
}
}
I Use Snapkit, Then, RxSwift, RxCocoa,NMapsMap.
please Help me.
When I run the code .asImage(), It had runtime error.
enter image description here