implement layer compare slider

projects/common-map/src/fm-map/components/map/map.component.ts

@@ -5,7 +5,7 @@ import { withLatestFrom, switchMap,skip  } from 'rxjs/operators';
 import { Router, ActivatedRoute, ParamMap } from '@angular/router';
 import { Store } from '@ngrx/store';
 import { DeviceService } from '@farmmaps/common';
-//import { proj,Map } from 'openlayers';
+import {getRenderPixel} from 'ol/render';
 
 // Map
 import * as mapReducers from '../../reducers/map.reducer';
@@ -76,6 +76,7 @@ export class MapComponent implements OnInit, OnDestroy,AfterViewInit {
   public clearEnabled$: Observable<boolean> = this.store.select(mapReducers.selectGetClearEnabled);
   public searchCollapsed$: Observable<boolean> = this.store.select(mapReducers.selectGetSearchCollapsed);
   public searchMinified$: Observable<boolean> = this.store.select(mapReducers.selectGetSearchMinified);
+  public showDataLayerSlide$: Observable<boolean> = this.store.select(mapReducers.selectGetShowdataLayerSlide);
   public menuVisible$: Observable<boolean>;
   public query$: Observable<IQuery> =  this.store.select(mapReducers.selectGetQuery);
   public position$: Observable<GeolocationPosition> = this.geolocationService.getCurrentPosition();
@@ -90,6 +91,9 @@ export class MapComponent implements OnInit, OnDestroy,AfterViewInit {
   public noContent: boolean = false;
   public overrideSelectedItemLayer: boolean = false;
   public overrideOverlayLayers: boolean = false;
+  public dataLayerSlideValue:number = 50;
+  public dataLayerSlideEnabled = false;
+  private visibleAreaBottom = 0;
   
   @ViewChild('map') map;
   @ViewChild('contentDiv') contentDiv: ElementRef;
@@ -155,6 +159,25 @@ export class MapComponent implements OnInit, OnDestroy,AfterViewInit {
     }
   }
 
+  handlePanelResize(resizeTop:number) {
+    if(resizeTop==100 || !this.devicesService.IsMobile() ) {
+      this.visibleAreaBottom=0;
+    } else {
+      this.visibleAreaBottom=100-resizeTop;
+      if(this.visibleAreaBottom>60) {
+        this.visibleAreaBottom=60;
+      }
+    }      
+  }
+
+  bottom(panelVisible:boolean) {
+    if(panelVisible) {
+      return this.visibleAreaBottom + '%';     
+    } else {
+      return "0%";
+    }
+  }
+
   handleOpenModal(modalName: string) {
     this.store.dispatch(new  commonActions.OpenModal(modalName));
   }
@@ -191,6 +214,31 @@ export class MapComponent implements OnInit, OnDestroy,AfterViewInit {
     }
   }
 
+  handlePrerender(event:any) {
+    if(!this.dataLayerSlideEnabled) return;
+    const ctx = event.context;
+    const mapSize = this.map.instance.getSize();
+    const width = mapSize[0] * (this.dataLayerSlideValue / 100);
+    const tl = getRenderPixel(event, [width, 0]);
+    const tr = getRenderPixel(event, [mapSize[0], 0]);
+    const bl = getRenderPixel(event, [width, mapSize[1]]);
+    const br = getRenderPixel(event, mapSize);
+
+    ctx.save();
+    ctx.beginPath();
+    ctx.moveTo(tl[0], tl[1]);
+    ctx.lineTo(bl[0], bl[1]);
+    ctx.lineTo(br[0], br[1]);
+    ctx.lineTo(tr[0], tr[1]);
+    ctx.closePath();
+    ctx.clip();
+  }
+
+  handleSlideChange(event:any) {
+     this.dataLayerSlideValue = event.target.value;
+     this.map.instance.render();
+  }
+
   ngOnInit() {    
     this.initialized = false;
     console.debug("Init");
@@ -323,6 +371,10 @@ export class MapComponent implements OnInit, OnDestroy,AfterViewInit {
         }
       });
     this.initialized = true;   
+    this.showDataLayerSlide$.subscribe((v) => {
+      this.dataLayerSlideEnabled=v;
+      this.map.instance.render();
+    });
   }
 
   handleSearchCollapse(event) {