Add overlay layer possibility, fix #515

UI/ShowDataLayer/ShowOverlayLayer.ts

@@ -0,0 +1,45 @@
+import TilesourceConfig from "../../Models/ThemeConfig/TilesourceConfig";
+import {UIEventSource} from "../../Logic/UIEventSource";
+import * as L from "leaflet";
+
+export default class ShowOverlayLayer {
+    
+    constructor(config: TilesourceConfig,
+                leafletMap: UIEventSource<any>,
+                isShown: UIEventSource<boolean> = undefined) {
+        
+        leafletMap.map(leaflet => {
+            if(leaflet === undefined){
+                return;
+            }
+
+            const tileLayer =  L.tileLayer(config.source,
+                {
+                    attribution: "",
+                    maxZoom: config.maxzoom,
+                    minZoom: config.minzoom,
+                    // @ts-ignore
+                    wmts: false,
+                });
+            
+            if(isShown === undefined){
+                tileLayer.addTo(leaflet)
+            }
+            
+            isShown?.addCallbackAndRunD(isShown => {
+                if(isShown){
+                    tileLayer.addTo(leaflet)
+                }else{
+                    leaflet.removeLayer(tileLayer)
+                }
+                
+            })
+            
+        } )
+        
+        
+        
+    }
+    
+    
+}