Add option to force loading of a layer, even if it is hidden + automatically set this flag is another layer depends on this layer

Logic/FeatureSource/FeaturePipeline.ts

@@ -23,7 +23,6 @@ import TileFreshnessCalculator from "./TileFreshnessCalculator";
 import FullNodeDatabaseSource from "./TiledFeatureSource/FullNodeDatabaseSource";
 import MapState from "../State/MapState";
 import {ElementStorage} from "../ElementStorage";
-import MetaTagging from "../MetaTagging";
 
 
 /**
@@ -373,7 +372,7 @@ export default class FeaturePipeline {
     private freshnessForVisibleLayers(z: number, x: number, y: number): Date {
         let oldestDate = undefined;
         for (const flayer of this.state.filteredLayers.data) {
-            if (!flayer.isDisplayed.data) {
+            if (!flayer.isDisplayed.data && !flayer.layerDef.forceLoad) {
                 continue
             }
             if (this.state.locationControl.data.zoom < flayer.layerDef.minzoom) {
@@ -399,6 +398,9 @@ export default class FeaturePipeline {
         return oldestDate
     }
 
+    /*
+    * Gives an UIEventSource containing the tileIndexes of the tiles that should be loaded from OSM
+    * */
     private getNeededTilesFromOsm(isSufficientlyZoomed: UIEventSource<boolean>): UIEventSource<number[]> {
         const self = this
         return this.state.currentBounds.map(bbox => {

Logic/FeatureSource/TiledFeatureSource/DynamicTileSource.ts

@@ -27,7 +27,7 @@ export default class DynamicTileSource implements TileHierarchy<FeatureSourceFor
         this.loadedTiles = new Map<number, FeatureSourceForLayer & Tiled>()
         const neededTiles = state.locationControl.map(
             location => {
-                if (!layer.isDisplayed.data) {
+                if (!layer.isDisplayed.data && !layer.layerDef.forceLoad) {
                     // No need to download! - the layer is disabled
                     return undefined;
                 }

Models/ThemeConfig/Conversion/PrepareTheme.ts

@@ -10,7 +10,6 @@ import LayerConfig from "../LayerConfig";
 import {TagRenderingConfigJson} from "../Json/TagRenderingConfigJson";
 import {SubstitutedTranslation} from "../../../UI/SubstitutedTranslation";
 import DependencyCalculator from "../DependencyCalculator";
-import {ValidateThemeAndLayers} from "./Validation";
 
 class SubstituteLayer extends Conversion<(string | LayerConfigJson), LayerConfigJson[]> {
     private readonly _state: DesugaringContext;
@@ -306,6 +305,13 @@ class AddDependencyLayersToTheme extends DesugaringStep<LayoutConfigJson> {
                 dependencies.push(...layerDeps)
             }
 
+            for (const dependency of dependencies) {
+                if(loadedLayerIds.has(dependency.neededLayer)){
+                    // We mark the needed layer as 'mustLoad'
+                    alreadyLoaded.find(l => l.id === dependency.neededLayer).forceLoad = true
+                }
+            }
+
             // During the generate script, builtin layers are verified but not loaded - so we have to add them manually here
             // Their existance is checked elsewhere, so this is fine
             unmetDependencies = dependencies.filter(dep => !loadedLayerIds.has(dep.neededLayer))
@@ -331,7 +337,11 @@ class AddDependencyLayersToTheme extends DesugaringStep<LayoutConfigJson> {
 
         } while (unmetDependencies.length > 0)
         
-        return dependenciesToAdd;
+        return dependenciesToAdd.map(dep => {
+            dep = Utils.Clone(dep);
+            dep.forceLoad = true
+            return dep
+        });
     }
 
     convert(theme: LayoutConfigJson, context: string): { result: LayoutConfigJson; errors: string[]; warnings: string[] } {

Models/ThemeConfig/Json/LayerConfigJson.ts

@@ -111,6 +111,13 @@ export interface LayerConfigJson {
      */
     isShown?: TagRenderingConfigJson;
 
+    /**
+     * Advanced option - might be set by the theme compiler
+     * 
+     * If true, this data will _always_ be loaded, even if the theme is disabled
+     */
+    forceLoad?: false | boolean
+
 
     /**
      * The minimum needed zoomlevel required before loading of the data start

Models/ThemeConfig/LayerConfig.ts

@@ -60,6 +60,7 @@ export default class LayerConfig extends WithContextLoader {
     public readonly tagRenderings: TagRenderingConfig[];
     public readonly filters: FilterConfig[];
     public readonly filterIsSameAs: string;
+    public readonly forceLoad: boolean;
     
     constructor(
         json: LayerConfigJson,
@@ -166,6 +167,7 @@ export default class LayerConfig extends WithContextLoader {
         this.minzoom = json.minzoom ?? 0;
         this.minzoomVisible = json.minzoomVisible ?? this.minzoom;
         this.shownByDefault = json.shownByDefault ?? true;
+        this.forceLoad = json.forceLoad ?? false;
         if (json.presets !== undefined && json.presets?.map === undefined) {
             throw "Presets should be a list of items (at " + context + ")"
         }