Add layergroup support

src/ol/layer/layergroup.js

@@ -0,0 +1,210 @@
+goog.provide('ol.layer.LayerGroup');
+
+goog.require('goog.array');
+goog.require('goog.asserts');
+goog.require('goog.events');
+goog.require('goog.events.EventType');
+goog.require('goog.math');
+goog.require('goog.object');
+goog.require('ol.Collection');
+goog.require('ol.CollectionEvent');
+goog.require('ol.CollectionEventType');
+goog.require('ol.Object');
+goog.require('ol.layer.Layer');
+goog.require('ol.layer.LayerBase');
+
+
+/**
+ * @enum {string}
+ */
+ol.layer.LayerGroupProperty = {
+  LAYERS: 'layers'
+};
+
+
+
+/**
+ * @constructor
+ * @extends {ol.layer.LayerBase}
+ * @param {ol.layer.LayerGroupOptions=} opt_options Layer options.
+ */
+ol.layer.LayerGroup = function(opt_options) {
+
+  var options = goog.isDef(opt_options) ? opt_options : {};
+  var baseOptions = /** @type {ol.layer.LayerGroupOptions} */
+      (goog.object.clone(options));
+  delete baseOptions.layers;
+
+  var layers = options.layers;
+
+  goog.base(this, baseOptions);
+
+  /**
+   * @private
+   * @type {Object.<string, goog.events.Key>}
+   */
+  this.listenerKeys_ = null;
+
+  goog.events.listen(this,
+      ol.Object.getChangeEventType(ol.layer.LayerGroupProperty.LAYERS),
+      this.handleLayersChanged_, false, this);
+
+  if (goog.isDef(layers)) {
+    if (goog.isArray(layers)) {
+      layers = new ol.Collection(goog.array.clone(layers));
+    } else {
+      goog.asserts.assertInstanceof(layers, ol.Collection);
+      layers = layers;
+    }
+  } else {
+    layers = new ol.Collection();
+  }
+
+  this.setLayers(layers);
+
+};
+goog.inherits(ol.layer.LayerGroup, ol.layer.LayerBase);
+
+
+/**
+ * @param {goog.events.Event} event Event.
+ * @private
+ */
+ol.layer.LayerGroup.prototype.handleLayersChanged_ = function(event) {
+  if (!goog.isNull(this.listenerKeys_)) {
+    goog.array.forEach(
+        goog.object.getValues(this.listenerKeys_), goog.events.unlistenByKey);
+    this.listenerKeys_ = null;
+  }
+
+  var layers = this.getLayers();
+  if (goog.isDefAndNotNull(layers)) {
+    this.listenerKeys_ = {
+      'add': goog.events.listen(layers, ol.CollectionEventType.ADD,
+          this.handleLayersAdd_, false, this),
+      'remove': goog.events.listen(layers, ol.CollectionEventType.REMOVE,
+          this.handleLayersRemove_, false, this)
+    };
+
+    var layersArray = layers.getArray();
+    var i, ii, layer;
+    for (i = 0, ii = layersArray.length; i < ii; i++) {
+      layer = layersArray[i];
+      this.listenerKeys_[goog.getUid(layer).toString()] =
+          goog.events.listen(layer, goog.events.EventType.CHANGE,
+              this.handleLayerChange_, false, this);
+    }
+  }
+
+  this.dispatchChangeEvent_();
+};
+
+
+/**
+ * @param {ol.CollectionEvent} collectionEvent Collection event.
+ * @private
+ */
+ol.layer.LayerGroup.prototype.handleLayersAdd_ = function(collectionEvent) {
+  var layer = /** @type {ol.layer.LayerBase} */ (collectionEvent.elem);
+  this.listenerKeys_[goog.getUid(layer).toString()] = goog.events.listen(
+      layer, goog.events.EventType.CHANGE, this.handleLayerChange_, false,
+      this);
+  this.dispatchChangeEvent_();
+};
+
+
+/**
+ * @param {ol.CollectionEvent} collectionEvent Collection event.
+ * @private
+ */
+ol.layer.LayerGroup.prototype.handleLayersRemove_ = function(collectionEvent) {
+  var layer = /** @type {ol.layer.LayerBase} */ (collectionEvent.elem);
+  var key = goog.getUid(layer).toString();
+  goog.events.unlistenByKey(this.listenerKeys_[key]);
+  delete this.listenerKeys_[key];
+  this.dispatchChangeEvent_();
+};
+
+
+/**
+ * @private
+ */
+ol.layer.LayerGroup.prototype.handleLayerChange_ = function() {
+  this.dispatchChangeEvent_();
+};
+
+
+/**
+ * @private
+ */
+ol.layer.LayerGroup.prototype.dispatchChangeEvent_ = function() {
+  this.dispatchEvent(goog.events.EventType.CHANGE);
+};
+
+
+/**
+ * @return {ol.Collection} Collection of layers.
+ */
+ol.layer.LayerGroup.prototype.getLayers = function() {
+  return /** @type {ol.Collection} */ (this.get(
+      ol.layer.LayerGroupProperty.LAYERS));
+};
+goog.exportProperty(
+    ol.layer.LayerGroup.prototype,
+    'getLayers',
+    ol.layer.LayerGroup.prototype.getLayers);
+
+
+/**
+ * @param {ol.Collection} layers Collection of layers.
+ */
+ol.layer.LayerGroup.prototype.setLayers = function(layers) {
+  this.set(ol.layer.LayerGroupProperty.LAYERS, layers);
+};
+goog.exportProperty(
+    ol.layer.LayerGroup.prototype,
+    'setLayers',
+    ol.layer.LayerGroup.prototype.setLayers);
+
+
+/**
+ * @inheritDoc
+ */
+ol.layer.LayerGroup.prototype.getLayerStatesArray = function(opt_obj) {
+  var obj = (goog.isDef(opt_obj)) ? opt_obj : {
+    layers: [],
+    layerStates: []
+  };
+  goog.asserts.assert(obj.layers.length === obj.layerStates.length);
+  var pos = obj.layers.length;
+
+  this.getLayers().forEach(function(layer) {
+    layer.getLayerStatesArray(obj);
+  });
+
+  var ownLayerState = this.getLayerState();
+  var i, ii, layerState;
+  for (i = pos, ii = obj.layerStates.length; i < ii; i++) {
+    layerState = obj.layerStates[i];
+    layerState.brightness = goog.math.clamp(
+        layerState.brightness + ownLayerState.brightness, -1, 1);
+    layerState.contrast *= ownLayerState.contrast;
+    layerState.hue += ownLayerState.hue;
+    layerState.opacity *= ownLayerState.opacity;
+    layerState.saturation *= ownLayerState.saturation;
+    layerState.visible = layerState.visible && ownLayerState.visible;
+  }
+
+  return obj;
+};
+
+
+/**
+ * @inheritDoc
+ */
+ol.layer.LayerGroup.prototype.isReady = function() {
+  return null === goog.array.find(
+      this.getLayers().getArray(), function(elt, index, array) {
+        return !elt.isReady();
+      });
+};