Merge pull request #9525 from jahow/custom-render-fn

Support a custom render function for the Layer class

examples/mapbox-layer.js

@@ -1,132 +1,12 @@
 import Map from '../src/ol/Map.js';
 import View from '../src/ol/View.js';
 import Layer from '../src/ol/layer/Layer';
-import {assign} from '../src/ol/obj';
 import {toLonLat} from '../src/ol/proj';
-import SourceState from '../src/ol/source/State';
 import {Stroke, Style} from '../src/ol/style.js';
 import VectorLayer from '../src/ol/layer/Vector.js';
 import VectorSource from '../src/ol/source/Vector.js';
 import GeoJSON from '../src/ol/format/GeoJSON.js';
 
-class Mapbox extends Layer {
-
-  /**
-   * @param {import('../src/ol/layer/Layer').Options} options Layer options.
-   */
-  constructor(options) {
-    const baseOptions = assign({}, options);
-    super(baseOptions);
-
-    this.baseOptions = baseOptions;
-
-    /**
-     * @private
-     * @type boolean
-     */
-    this.loaded = false;
-
-    this.initMap();
-  }
-
-  initMap() {
-    const map = this.map_;
-    const view = map.getView();
-    const center = toLonLat(view.getCenter(), view.getProjection());
-
-    const options = assign(this.baseOptions, {
-      attributionControl: false,
-      boxZoom: false,
-      center,
-      container: map.getTargetElement(),
-      doubleClickZoom: false,
-      dragPan: false,
-      dragRotate: false,
-      interactive: false,
-      keyboard: false,
-      pitchWithRotate: false,
-      scrollZoom: false,
-      touchZoomRotate: false,
-      zoom: view.getZoom() - 1
-    });
-
-    this.mbmap = new mapboxgl.Map(options);
-
-    this.mbmap.on('load', function() {
-      this.loaded = true;
-      this.map_.render();
-      this.mbmap.getContainer().querySelector('.mapboxgl-control-container').remove();
-    }.bind(this));
-
-  }
-
-  /**
-   *
-   * @inheritDoc
-   */
-  render(frameState) {
-    const map = this.map_;
-    const view = map.getView();
-
-    // adjust view parameters in mapbox
-    const rotation = frameState.viewState.rotation;
-    if (rotation) {
-      this.mbmap.rotateTo(-rotation * 180 / Math.PI, {
-        animate: false
-      });
-    }
-    const center = toLonLat(view.getCenter(), view.getProjection());
-    const zoom = view.getZoom() - 1;
-    this.mbmap.jumpTo({
-      center: center,
-      zoom: zoom,
-      animate: false
-    });
-
-    // cancel the scheduled update & trigger synchronous redraw
-    // see https://github.com/mapbox/mapbox-gl-js/issues/7893#issue-408992184
-    // NOTE: THIS MIGHT BREAK WHEN UPDATING MAPBOX
-    if (this.mbmap._frame) {
-      this.mbmap._frame.cancel();
-      this.mbmap._frame = null;
-    }
-    this.mbmap._render();
-
-    return this.mbmap.getCanvas();
-  }
-
-  setVisible(visible) {
-    super.setVisible(visible);
-
-    const canvas = this.mbmap.getCanvas();
-    canvas.style.display = visible ? 'block' : 'none';
-  }
-
-  setOpacity(opacity) {
-    super.setOpacity(opacity);
-    const canvas = this.mbmap.getCanvas();
-    canvas.style.opacity = opacity;
-  }
-
-  setZIndex(zindex) {
-    super.setZIndex(zindex);
-    const canvas = this.mbmap.getCanvas();
-    canvas.style.zIndex = zindex;
-  }
-
-  /**
-   * @inheritDoc
-   */
-  getSourceState() {
-    return this.loaded ? SourceState.READY : SourceState.UNDEFINED;
-  }
-
-  setMap(map) {
-    this.map_ = map;
-  }
-
-}
-
 const style = new Style({
   stroke: new Stroke({
     color: '#319FD3',
@@ -154,11 +34,71 @@ const map = new Map({
   })
 });
 
+
+// init Mapbox object
+
+const view = map.getView();
+const center = toLonLat(view.getCenter(), view.getProjection());
 const key = 'ER67WIiPdCQvhgsUjoWK';
-const mbLayer = new Mapbox({
-  map: map,
+
+const mbMap = new mapboxgl.Map({
+  style: 'https://maps.tilehosting.com/styles/bright/style.json?key=' + key,
+  attributionControl: false,
+  boxZoom: false,
+  center: center,
+  container: map.getTargetElement(),
+  doubleClickZoom: false,
+  dragPan: false,
+  dragRotate: false,
+  interactive: false,
+  keyboard: false,
+  pitchWithRotate: false,
+  scrollZoom: false,
+  touchZoomRotate: false,
+  zoom: view.getZoom() - 1
+});
+
+
+// init OL layers
+
+const mbLayer = new Layer({
   container: map.getTarget(),
-  style: 'https://maps.tilehosting.com/styles/bright/style.json?key=' + key
+  render: function(frameState) {
+    const canvas = mbMap.getCanvas();
+    const view = map.getView();
+
+    const visible = mbLayer.getVisible();
+    canvas.style.display = visible ? 'block' : 'none';
+
+    const opacity = mbLayer.getOpacity();
+    canvas.style.opacity = opacity;
+
+    // adjust view parameters in mapbox
+    const rotation = frameState.viewState.rotation;
+    if (rotation) {
+      mbMap.rotateTo(-rotation * 180 / Math.PI, {
+        animate: false
+      });
+    }
+    const center = toLonLat(view.getCenter(), view.getProjection());
+    const zoom = view.getZoom() - 1;
+    mbMap.jumpTo({
+      center: center,
+      zoom: zoom,
+      animate: false
+    });
+
+    // cancel the scheduled update & trigger synchronous redraw
+    // see https://github.com/mapbox/mapbox-gl-js/issues/7893#issue-408992184
+    // NOTE: THIS MIGHT BREAK WHEN UPDATING MAPBOX
+    if (mbMap._frame) {
+      mbMap._frame.cancel();
+      mbMap._frame = null;
+    }
+    mbMap._render();
+
+    return canvas;
+  }
 });
 
 map.addLayer(mbLayer);

src/ol/layer/Layer.js

@@ -10,6 +10,10 @@ import {assign} from '../obj.js';
 import RenderEventType from '../render/EventType.js';
 import SourceState from '../source/State.js';
 
+/**
+ * @typedef {function(import("../PluggableMap.js").FrameState):HTMLElement} RenderFunction
+ */
+
 
 /**
  * @typedef {Object} Options
@@ -29,6 +33,8 @@ import SourceState from '../source/State.js';
  * the source can be set by calling {@link module:ol/layer/Layer#setSource layer.setSource(source)} after
  * construction.
  * @property {import("../PluggableMap.js").default} [map] Map.
+ * @property {RenderFunction} [render] Render function. Takes the frame state as input and is expected to return an
+ * HTML element. Will overwrite the default rendering for the layer.
  */
 
 
@@ -47,8 +53,10 @@ import SourceState from '../source/State.js';
 
 /**
  * @classdesc
- * Abstract base class; normally only used for creating subclasses and not
- * instantiated in apps.
+ * Base class from which all layer types are derived. This should only be instantiated
+ * in the case where a custom layer is be added to the map with a custom `render` function.
+ * Such a function can be specified in the `options` object, and is expected to return an HTML element.
+ *
  * A visual representation of raster or vector map data.
  * Layers group together those properties that pertain to how the data is to be
  * displayed, irrespective of the source of that data.
@@ -64,6 +72,7 @@ import SourceState from '../source/State.js';
  * @fires import("../render/Event.js").RenderEvent#postrender
  *
  * @template {import("../source/Source.js").default} SourceType
+ * @api
  */
 class Layer extends BaseLayer {
   /**
@@ -100,6 +109,11 @@ class Layer extends BaseLayer {
      */
     this.renderer_ = null;
 
+    // Overwrite default render method with a custom one
+    if (options.render) {
+      this.render = options.render;
+    }
+
     if (options.map) {
       this.setMap(options.map);
     }

src/ol/renderer/Composite.js

@@ -85,7 +85,8 @@ class CompositeMapRenderer extends MapRenderer {
     this.children_.length = 0;
     for (let i = 0, ii = layerStatesArray.length; i < ii; ++i) {
       const layerState = layerStatesArray[i];
-      if (!visibleAtResolution(layerState, viewResolution) || layerState.sourceState != SourceState.READY) {
+      if (!visibleAtResolution(layerState, viewResolution) ||
+        (layerState.sourceState != SourceState.READY && layerState.sourceState != SourceState.UNDEFINED)) {
         continue;
       }
 

test/spec/ol/layer/layer.test.js

@@ -94,6 +94,16 @@ describe('ol.layer.Layer', function() {
       layer.dispose();
     });
 
+    it('accepts a custom render function', function() {
+      let called = false;
+      const layer = new Layer({
+        render: function() {
+          called = true;
+        }
+      });
+      layer.render();
+      expect(called).to.eql(true);
+    });
   });
 
   describe('visibleAtResolution', function() {