Give points a getCentroid/centroid method.

src/api/geom/point.js

@@ -1,4 +1,4 @@
-goog.provide('ol.geom.point'); 
+goog.provide('ol.geom.point');
 
 goog.require('ol.geom.Point');
 goog.require('ol.projection');
@@ -14,23 +14,23 @@ ol.PointLike;
  * @return {ol.geom.Point} Point.
  */
 ol.geom.point = function(opt_arg){
-    
+
     if (opt_arg instanceof ol.geom.Point) {
         return opt_arg;
     }
-    
+
     var x = 0;
     var y = 0;
     var z;
     var projection;
-    
+
     if (arguments.length == 1 && goog.isDef(opt_arg)) {
         if (goog.isArray(opt_arg)) {
             x = opt_arg[0];
             y = opt_arg[1];
             z = opt_arg[2];
             projection = opt_arg[3];
-            
+
         } else if (goog.isObject(opt_arg)) {
             x = opt_arg['x'];
             y = opt_arg['y'];
@@ -43,7 +43,7 @@ ol.geom.point = function(opt_arg){
     if (goog.isDef(projection)) {
         projection = ol.projection(projection);
     }
-    
+
     var p = new ol.geom.Point(x,y,z,projection);
     return p;
 };
@@ -110,4 +110,13 @@ ol.geom.Point.prototype.projection = function(opt_arg){
     else {
         return this.getProjection();
     }
-};
+};
+
+/**
+ * Returns the centroid of this point; which is a clone of the point itself.
+ *
+ * @return {ol.geom.Point} The centroid.
+ */
+ol.geom.Point.prototype.centroid = function() {
+    return this.getCentroid();
+};

src/ol/geom/Point.js

@@ -7,17 +7,17 @@ goog.require('ol.coord.AccessorInterface');
 goog.require('ol.base');
 
 /**
- * Creates ol.geom.Point objects. 
- * 
+ * Creates ol.geom.Point objects.
+ *
  * @export
  * @extends {ol.geom.Geometry}
  * @param {number} x X.
  * @param {number} y Y.
  * @param {number=} opt_z Z.
  * @param {ol.Projection=} opt_projection Projection.
- * 
+ *
  * @implements {ol.coord.AccessorInterface}
- * 
+ *
  * @constructor
  */
 ol.geom.Point = function(x, y, opt_z, opt_projection) {
@@ -26,19 +26,19 @@ ol.geom.Point = function(x, y, opt_z, opt_projection) {
      * @type {number}
      */
     this.x_ = x;
-    
+
     /**
      * @private
      * @type {number}
      */
     this.y_ = y;
-    
+
     /**
      * @private
      * @type {number|undefined}
      */
     this.z_ = opt_z;
-    
+
     /**
      * @private
      * @type {ol.Projection}
@@ -109,12 +109,12 @@ ol.geom.Point.prototype.setZ = function(z) {
 };
 
 /**
- * Transform this point to another coordinate reference system.  This 
+ * Transform this point to another coordinate reference system.  This
  * requires that this point has a projection set already (if not, an error
  * will be thrown).  Returns a new point object and does not modify this
  * point.
  *
- * @param {string|!ol.Projection} proj The destination projection.  Can be 
+ * @param {string|!ol.Projection} proj The destination projection.  Can be
  *     supplied as a projection instance of a string identifier.
  * @returns {!ol.geom.Point} A new location.
  */
@@ -140,7 +140,24 @@ ol.geom.Point.prototype._transform = function(proj) {
         ol.error(msg);
     }
     ol.Projection.transform(point, sourceProj, proj);
-    
+
     return new ol.geom.Point(point['x'], point['y'], this.z_, proj);
 };
 
+/**
+ * Returns the centroid of the point.
+ *
+ * @returns {ol.geom.Point} The centroid of the point.
+ */
+ol.geom.Point.prototype.getCentroid = function() {
+    return new ol.geom.Point(this.x_, this.y_, this.z_, this.projection_);
+};
+
+/**
+ * Returns the area of the geometry whcih is always 0.
+ *
+ * @returns {number} The area of the point (always 0).
+ */
+ol.geom.Point.prototype.getArea = function() {
+    return 0;
+};

test/spec/api/geom/point.test.js

@@ -166,4 +166,47 @@ describe("ol.geom.point", function() {
             expect(p_obj.projection()).toEqual(jasmine.any(ol.Projection));
         });
     });
+
+    describe("the centroid method is functional", function(){
+        it("returns an instance of ol.geom.Point", function(){
+            expect(pNoZ_arr.centroid()).toBeA(ol.geom.Point);
+            expect(pWithZ_arr.centroid()).toBeA(ol.geom.Point);
+            expect(p_arr.centroid()).toBeA(ol.geom.Point);
+
+            expect(pNoZ_obj.centroid()).toBeA(ol.geom.Point);
+            expect(pWithZ_obj.centroid()).toBeA(ol.geom.Point);
+            expect(p_obj.centroid()).toBeA(ol.geom.Point);
+        });
+
+        it("does return a clone and not the point itself", function(){
+            expect(pNoZ_arr.centroid()).not.toBe(pNoZ_arr);
+            expect(pWithZ_arr.centroid()).not.toBe(pWithZ_arr);
+            expect(p_arr.centroid()).not.toBe(p_arr);
+
+            expect(pNoZ_obj.centroid()).not.toBe(pNoZ_obj);
+            expect(pWithZ_obj.centroid()).not.toBe(pWithZ_obj);
+            expect(p_obj.centroid()).not.toBe(p_obj);
+        });
+
+        it("has the expected coordinates", function(){
+            var c1 = pNoZ_arr.centroid(),
+                c2 = pWithZ_arr.centroid(),
+                c3 = p_arr.centroid(),
+                c4 = pNoZ_obj.centroid(),
+                c5 = pWithZ_obj.centroid(),
+                c6 = p_obj.centroid();
+
+            expect(c1.x() + ',' + c1.y()).toBe('21,4');
+            expect(c2.x() + ',' + c2.y()).toBe('21,4');
+            expect(c3.x() + ',' + c3.y()).toBe('21,4');
+            expect(c4.x() + ',' + c4.y()).toBe('21,4');
+            expect(c5.x() + ',' + c5.y()).toBe('21,4');
+            expect(c6.x() + ',' + c6.y()).toBe('21,4');
+        });
+
+        it("returns point(0,0) when the point was constructed without args", function(){
+            var c = pNoArgs.centroid();
+            expect(c.x() + ',' + c.y()).toBe('0,0');
+        });
+    });
 });

test/spec/ol/geom/Point.test.js

@@ -123,4 +123,27 @@ describe("ol.geom.Point", function() {
         });
     });
 
+    describe("the getCentroid method is functional", function(){
+        it("returns an instance of ol.geom.Point", function(){
+            expect(p2Args.getCentroid()).toBeA(ol.geom.Point);
+            expect(p3Args.getCentroid()).toBeA(ol.geom.Point);
+            expect(p4Args.getCentroid()).toBeA(ol.geom.Point);
+        });
+
+        it("does return a clone and not the point itself", function(){
+            expect(p2Args.getCentroid()).not.toBe(p2Args);
+            expect(p3Args.getCentroid()).not.toBe(p3Args);
+            expect(p4Args.getCentroid()).not.toBe(p4Args);
+        });
+
+        it("has the expected coordinates", function(){
+            var c2 = p2Args.getCentroid(),
+                c3 = p3Args.getCentroid(),
+                c4 = p4Args.getCentroid();
+
+            expect(c2.getX() + ',' + c2.getY()).toBe('21,4');
+            expect(c3.getX() + ',' + c3.getY()).toBe('21,4');
+            expect(c4.getX() + ',' + c4.getY()).toBe('21,4');
+        });
+    });
 });