Make Points transformable.

src/ol/geom/Point.js

@@ -106,3 +106,37 @@ ol.geom.Point.prototype.setZ = function(z) {
     this.z_ = z;
 };
 
+/**
+ * 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 
+ *     supplied as a projection instance of a string identifier.
+ * @returns {!ol.geom.Point} A new location.
+ */
+ol.geom.Point.prototype.transform = function(proj) {
+    if (goog.isString(proj)) {
+        proj = new ol.Projection(proj);
+    }
+    return this.transform_(proj);
+};
+
+/**
+ * Transform this point to a new location given a projection object.
+ *
+ * @param {!ol.Projection} proj The destination projection.
+ * @returns {!ol.geom.Point}
+ * @private
+ */
+ol.geom.Point.prototype.transform_ = function(proj) {
+    var point = {x: this.x_, y: this.y_};
+    var sourceProj = this.projection_;
+    if (!goog.isDefAndNotNull(sourceProj)) {
+        throw new Error("Cannot transform a point without a source projection.");
+    }
+    ol.Projection.transform(point, sourceProj, proj);
+    return new ol.geom.Point(point.x, point.y, this.z_, proj);
+};
+

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

@@ -2,7 +2,6 @@ describe("ol.geom.Point", function() {
     var p2Args,
         p3Args,
         p4Args,
-        p_arr,
         proj = "EPSG:4326";
         
     var instances = {
@@ -57,6 +56,7 @@ describe("ol.geom.Point", function() {
                 expect(instance.getProjection).not.toBeUndefined();
                 expect(instance.setProjection).not.toBeUndefined();
             });
+            
         }
     }
     
@@ -83,4 +83,41 @@ describe("ol.geom.Point", function() {
         expect(p4Args.getProjection()).not.toBeNull();
         expect(p4Args.getProjection()).toBeA(ol.Projection);
     });
+    
+    it("can be transformed", function(){
+        // save for later comparison
+        var old = {
+            x: p4Args.getX().toFixed(3),
+            y: p4Args.getY().toFixed(3)
+        };
+        // with code only
+        var transformedPoint = p4Args.transform("EPSG:3857");
+        
+        // is it still an instance of ol.geom.Point?
+        expect(transformedPoint).toBeA(ol.geom.Point);
+        // coordinates OK?
+        expect(transformedPoint.getX().toFixed(3)).toBe("2337709.306");
+        expect(transformedPoint.getY().toFixed(3)).toBe("445640.110");
+        
+        // with an ol.Projection
+        var retransformedPoint = transformedPoint.transform(new ol.Projection("EPSG:4326"));
+        expect(retransformedPoint).toBeA(ol.geom.Point);
+        
+        // coordinates shopulkd be the originally configured
+        expect(retransformedPoint.getX().toFixed(3)).toBe(old.x);
+        expect(retransformedPoint.getY().toFixed(3)).toBe(old.y);
+    });
+    
+    it("throws an exception when you try to transform without a source projection", function(){
+        
+        expect(function() {
+            p2Args.transform("EPSG:3857");
+        }).toThrow();
+        
+        expect(function() {
+            p3Args.transform("EPSG:3857");
+        }).toThrow();
+        
+    });
+
 });