Add ol.source.Cluster

Initial code by @kenny806
2014-07-24 17:58:41 +02:00
parent 77674c6728
commit 06df648733
5 changed files with 363 additions and 0 deletions
--- a/src/ol/source/clustersource.js
+++ b/src/ol/source/clustersource.js
@@ -0,0 +1,150 @@
+// FIXME keep cluster cache by resolution ?
+// FIXME distance not respected because of the centroid
+
+goog.provide('ol.source.Cluster');
+
+goog.require('goog.array');
+goog.require('goog.asserts');
+goog.require('goog.events.EventType');
+goog.require('goog.object');
+goog.require('ol.Feature');
+goog.require('ol.coordinate');
+goog.require('ol.extent');
+goog.require('ol.geom.Point');
+goog.require('ol.source.Vector');
+
+
+
+/**
+ * @constructor
+ * @param {olx.source.ClusterOptions} options
+ * @extends {ol.source.Vector}
+ * @api
+ */
+ol.source.Cluster = function(options) {
+  goog.base(this, {
+    attributions: options.attributions,
+    extent: options.extent,
+    logo: options.logo,
+    projection: options.projection
+  });
+
+  /**
+   * @type {number|undefined}
+   * @private
+   */
+  this.resolution_ = undefined;
+
+  /**
+   * @type {number}
+   * @private
+   */
+  this.distance_ = goog.isDef(options.distance) ? options.distance : 20;
+
+  /**
+   * @type {Array.<ol.Feature>}
+   * @private
+   */
+  this.features_ = [];
+
+  /**
+   * @type {ol.source.Vector}
+   * @private
+   */
+  this.source_ = options.source;
+
+  this.source_.on(goog.events.EventType.CHANGE,
+      ol.source.Cluster.prototype.onSourceChange_, this);
+};
+goog.inherits(ol.source.Cluster, ol.source.Vector);
+
+
+/**
+ * @param {ol.Extent} extent
+ * @param {number} resolution
+ */
+ol.source.Cluster.prototype.loadFeatures = function(extent, resolution) {
+  if (resolution !== this.resolution_) {
+    this.clear();
+    this.resolution_ = resolution;
+    this.cluster_();
+    this.addFeatures(this.features_);
+  }
+};
+
+
+/**
+ * handle the source changing
+ * @private
+ */
+ol.source.Cluster.prototype.onSourceChange_ = function() {
+  this.clear();
+  this.cluster_();
+  this.addFeatures(this.features_);
+  this.dispatchChangeEvent();
+};
+
+
+/**
+ * @private
+ */
+ol.source.Cluster.prototype.cluster_ = function() {
+  goog.array.clear(this.features_);
+  var extent = ol.extent.createEmpty();
+  goog.asserts.assert(goog.isDef(this.resolution_));
+  var mapDistance = this.distance_ * this.resolution_;
+  var features = this.source_.getFeatures();
+
+  /**
+   * @type {Object.<string, boolean>}
+   */
+  var clustered = {};
+
+  for (var i = 0, ii = features.length; i < ii; i++) {
+    var feature = features[i];
+    if (!goog.object.containsKey(clustered, goog.getUid(feature).toString())) {
+      var geometry = feature.getGeometry();
+      goog.asserts.assert(geometry instanceof ol.geom.Point);
+      var coordinates = geometry.getCoordinates();
+      ol.extent.createOrUpdateFromCoordinate(coordinates, extent);
+      ol.extent.buffer(extent, mapDistance, extent);
+
+      var neighbors = this.source_.getFeaturesInExtent(extent);
+      goog.asserts.assert(neighbors.length >= 1);
+      neighbors = goog.array.filter(neighbors, function(neighbor) {
+        var uid = goog.getUid(neighbor).toString();
+        if (!goog.object.containsKey(clustered, uid)) {
+          goog.object.set(clustered, uid, true);
+          return true;
+        } else {
+          return false;
+        }
+      });
+      this.features_.push(this.createCluster_(neighbors));
+    }
+  }
+  goog.asserts.assert(
+      goog.object.getCount(clustered) == this.source_.getFeatures().length);
+};
+
+
+/**
+ * @param {Array.<ol.Feature>} features Features
+ * @return {ol.Feature}
+ * @private
+ */
+ol.source.Cluster.prototype.createCluster_ = function(features) {
+  var length = features.length;
+  var centroid = [0, 0];
+  for (var i = 0; i < length; i++) {
+    var geometry = features[i].getGeometry();
+    goog.asserts.assert(geometry instanceof ol.geom.Point);
+    var coordinates = geometry.getCoordinates();
+    ol.coordinate.add(centroid, coordinates);
+  }
+  ol.coordinate.scale(centroid, 1 / length);
+
+  var cluster = new ol.Feature(new ol.geom.Point(centroid));
+  cluster.set('features', features);
+  return cluster;
+};