Add overlay layer possibility, fix #515

Models/ThemeConfig/Json/LayoutConfigJson.ts

@@ -1,5 +1,7 @@
 import {TagRenderingConfigJson} from "./TagRenderingConfigJson";
 import {LayerConfigJson} from "./LayerConfigJson";
+import TilesourceConfig from "../TilesourceConfig";
+import TilesourceConfigJson from "./TilesourceConfigJson";
 
 /**
  * Defines the entire theme.
@@ -155,6 +157,11 @@ export interface LayoutConfigJson {
      */
     defaultBackgroundId?: string;
 
+    /**
+     * Define some (overlay) slippy map tilesources
+     */
+    tileLayerSources?: TilesourceConfigJson[]
+
     /**
      * The number of seconds that a feature is allowed to stay in the cache.
      * The caching flow is as following:

Models/ThemeConfig/Json/TilesourceConfigJson.ts

@@ -0,0 +1,36 @@
+/**
+ * Configuration for a tilesource config
+ */
+export default interface TilesourceConfigJson {
+
+
+    /**
+     * The path, where {x}, {y} and {z} will be substituted
+     */
+    source: string,
+    
+    isOverlay?: boolean,
+
+    /**
+     * How this will be shown in the selection menu.
+     * Make undefined if this may not be toggled
+     */
+    name?: any | string
+
+    /**
+     * Only visible at this or a higher zoom level
+     */
+    minZoom?: number
+
+    /**
+     * Only visible at this or a lower zoom level
+     */
+    maxZoom?: number
+
+
+    /**
+     * The default state, set to false to hide by default
+     */
+    defaultState: boolean;
+
+}

Models/ThemeConfig/LayoutConfig.ts

@@ -7,6 +7,7 @@ import {Utils} from "../../Utils";
 import LayerConfig from "./LayerConfig";
 import {LayerConfigJson} from "./Json/LayerConfigJson";
 import Constants from "../Constants";
+import TilesourceConfig from "./TilesourceConfig";
 
 export default class LayoutConfig {
     public readonly id: string;
@@ -27,6 +28,7 @@ export default class LayoutConfig {
     public readonly roamingRenderings: TagRenderingConfig[];
     public readonly defaultBackgroundId?: string;
     public layers: LayerConfig[];
+    public tileLayerSources: TilesourceConfig[]
     public readonly clustering?: {
         maxZoom: number,
         minNeededElements: number,
@@ -108,6 +110,7 @@ export default class LayoutConfig {
             }
         );
         this.defaultBackgroundId = json.defaultBackgroundId;
+        this.tileLayerSources = (json.tileLayerSources??[]).map((config, i) => new TilesourceConfig(config, `${this.id}.tileLayerSources[${i}]`))
         this.layers = LayoutConfig.ExtractLayers(json, official, context);
 
         // ALl the layers are constructed, let them share tagRenderings now!

Models/ThemeConfig/TilesourceConfig.ts

@@ -0,0 +1,38 @@
+import TilesourceConfigJson from "./Json/TilesourceConfigJson";
+import Translations from "../../UI/i18n/Translations";
+import {Translation} from "../../UI/i18n/Translation";
+
+export default class TilesourceConfig {
+    public readonly source: string
+    public readonly isOverlay: boolean
+    public readonly name: Translation
+    public readonly minzoom: number
+    public readonly maxzoom: number
+    public readonly defaultState: boolean;
+
+    constructor(config: TilesourceConfigJson, ctx: string = "") {
+
+        this.source = config.source;
+        this.isOverlay = config.isOverlay ?? false;
+        this.name = Translations.T(config.name)
+        this.minzoom = config.minZoom ?? 0
+        this.maxzoom = config.maxZoom ?? 999
+        this.defaultState = config.defaultState ?? true;
+        if (this.minzoom > this.maxzoom) {
+            throw "Invalid tilesourceConfig: minzoom should be smaller then maxzoom (at " + ctx + ")"
+        }
+        if (this.minzoom < 0) {
+            throw "minzoom should be > 0 (at " + ctx + ")"
+        }
+        if (this.maxzoom < 0) {
+            throw "maxzoom should be > 0 (at " + ctx + ")"
+        }
+        if (this.source.indexOf("{zoom}") >= 0) {
+            throw "Invalid source url: use {z} instead of {zoom}  (at " + ctx + ".source)"
+        }
+        if(!this.defaultState && config.name === undefined){
+            throw "Disabling an overlay without a name is not possible"
+        }
+    }
+
+}