Overlay tiles on Google Maps (Swift 3) - google-maps

Question

I'm developing an application in Swift 3.0 and iOS10, with the Google Maps SDK.
The application calls WMS with "GMSTileURLConstructor" to make mosaic overlays on the Google Maps map. The overlay is correct at the position level, but the problem is that in the tiles "empty" where the mosaic is not and returns an empty tile, it is a png image, but when changing the opacity of the tile "tileLayer.opacity = 0.2" Makes transparent both the tiles of the supermosaic and the tiles of png and that is why the screen remains like this. Where they are useful with a white color. What solution do you give me? Because I have the bbox on the supermosaic server, is there any way to just make calls about that bbox?
The code in ViewController is:
import UIKit
class ViewController: UIViewController, CLLocationManagerDelegate
{
#IBOutlet weak var mapview: GMSMapView!
let locationManager = CLLocationManager()
let layer: WMSTileOverlay
var url = ""
override func viewDidLoad() {
super.viewDidLoad()
locationManager.delegate = self
locationManager.requestWhenInUseAuthorization()
mapview.isMyLocationEnabled = true
mapview.settings.myLocationButton = true
url = ""
self.getCardfromGeoserver()
self.mapview.mapType = .satellite
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
required init?(coder aDecoder: NSCoder) {
self.layer = WMSTileOverlay(urlArg: url)
super.init(coder: aDecoder)
}
// Warnung ueber Geoserver holen
func getCardfromGeoserver() {
mapview.clear()
//mapview.camera = GMSCameraPosition(target: CLLocationCoordinate2D(latitude: 37.529332577842005, longitude: -6.097075880344892), zoom: 17.5, bearing: 0, viewingAngle: 0)
mapview.camera = GMSCameraPosition(target: CLLocationCoordinate2D(latitude: 41.2514352951879, longitude: 0.6398317662822497), zoom: 17, bearing: 0, viewingAngle: 0)
let urls: GMSTileURLConstructor = { (x: UInt, y: UInt, zoom: UInt) -> URL in
let bbox = self.layer.bboxFromXYZ(x, y: y, z: zoom)
let urlKN = "http://localhost:8080/geoserver/cite/wms?SERVICE=WMS&VERSION=1.1.0&REQUEST=GetMap&FORMAT=image%2Fpng&TRANSPARENT=true&STYLES&LAYERS=cite%3A17_RGB&WIDTH=256&HEIGHT=256&SRS=EPSG%3A3857&BBOX=\(bbox.left),\(bbox.bottom),\(bbox.right),\(bbox.top)"
print(urlKN)
return URL(string: urlKN)!
}
let tileLayer = GMSURLTileLayer(urlConstructor: urls)
tileLayer.opacity = 0.2
tileLayer.zIndex = 1
tileLayer.map = nil
tileLayer.map = mapview
}
func locationManager(_ manager: CLLocationManager, didChangeAuthorization status: CLAuthorizationStatus) {
if status == CLAuthorizationStatus.authorizedWhenInUse {
locationManager.startUpdatingLocation()
mapview.isMyLocationEnabled = true
mapview.settings.myLocationButton = true
}
}
}
The code for WMSTileOverlay is:
import UIKit
class ViewController: UIViewController, CLLocationManagerDelegate {
#IBOutlet weak var mapview: GMSMapView!
let locationManager = CLLocationManager()
let layer: WMSTileOverlay
var url = ""
override func viewDidLoad() {
super.viewDidLoad()
locationManager.delegate = self
locationManager.requestWhenInUseAuthorization()
mapview.isMyLocationEnabled = true
mapview.settings.myLocationButton = true
url = ""
self.getCardfromGeoserver()
self.mapview.mapType = .satellite
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
required init?(coder aDecoder: NSCoder) {
self.layer = WMSTileOverlay(urlArg: url)
super.init(coder: aDecoder)
}
// Warnung ueber Geoserver holen
func getCardfromGeoserver() {
mapview.clear()
//mapview.camera = GMSCameraPosition(target: CLLocationCoordinate2D(latitude: 37.529332577842005, longitude: -6.097075880344892), zoom: 17.5, bearing: 0, viewingAngle: 0)
mapview.camera = GMSCameraPosition(target: CLLocationCoordinate2D(latitude: 41.2514352951879, longitude: 0.6398317662822497), zoom: 17, bearing: 0, viewingAngle: 0)
let urls: GMSTileURLConstructor = { (x: UInt, y: UInt, zoom: UInt) -> URL in
let bbox = self.layer.bboxFromXYZ(x, y: y, z: zoom)
let urlKN = "http://localhost:8080/geoserver/cite/wms?SERVICE=WMS&VERSION=1.1.0&REQUEST=GetMap&FORMAT=image%2Fpng&TRANSPARENT=true&STYLES&LAYERS=cite%3A17_RGB&WIDTH=256&HEIGHT=256&SRS=EPSG%3A3857&BBOX=\(bbox.left),\(bbox.bottom),\(bbox.right),\(bbox.top)"
print(urlKN)
return URL(string: urlKN)!
}
let tileLayer = GMSURLTileLayer(urlConstructor: urls)
tileLayer.opacity = 0.2
tileLayer.zIndex = 1
tileLayer.map = nil
tileLayer.map = mapview
}
func locationManager(_ manager: CLLocationManager, didChangeAuthorization status: CLAuthorizationStatus) {
if status == CLAuthorizationStatus.authorizedWhenInUse {
locationManager.startUpdatingLocation()
mapview.isMyLocationEnabled = true
mapview.settings.myLocationButton = true
}
}
}