Add getBounds to geometry

src/ol/geom/geometrycollection.js

@@ -0,0 +1,70 @@
+goog.provide('ol.geom.GeometryCollection');
+
+goog.require('goog.asserts');
+goog.require('ol.Extent');
+goog.require('ol.geom.Geometry');
+
+
+
+/**
+ * A mixed collection of geometries.  This constructor is typically not called
+ * directly.  Instead call @see ol.geom.GeometryCollection#fromGeometries.
+ * @constructor
+ * @implements {ol.geom.Geometry}
+ */
+ol.geom.GeometryCollection = function() {
+
+  /**
+   * @type {Array.<ol.geom.Geometry>}
+   */
+  this.components = null;
+
+  /**
+   * @type {number}
+   */
+  this.dimension;
+
+  /**
+   * @type {ol.Extent}
+   * @protected
+   */
+  this.bounds = null;
+
+};
+
+
+/**
+ * @inheritDoc
+ */
+ol.geom.GeometryCollection.prototype.getBounds = function() {
+  if (goog.isNull(this.bounds)) {
+    var minX,
+        minY = minX = Number.POSITIVE_INFINITY,
+        maxX,
+        maxY = maxX = Number.NEGATIVE_INFINITY,
+        components = this.components,
+        len = components.length,
+        bounds, i;
+
+    for (i = 0; i < len; ++i) {
+      bounds = components[i].getBounds();
+      minX = Math.min(bounds.minX, minX);
+      minY = Math.min(bounds.minY, minY);
+      maxX = Math.max(bounds.maxX, maxX);
+      maxY = Math.max(bounds.maxY, maxY);
+    }
+    this.bounds = new ol.Extent(minX, minY, maxX, maxY);
+  }
+  return this.bounds;
+};
+
+
+/**
+ * @param {Array.<ol.geom.Geometry>} components Array of geometries.
+ * @return {ol.geom.GeometryCollection} A mixed geometry collection.
+ */
+ol.geom.GeometryCollection.fromGeometries = function(components) {
+  var collection = new ol.geom.GeometryCollection();
+  collection.components = components;
+  return collection;
+};