Correctly set default anchor for collections

src/ol/geom/geometrycollection.js

@@ -249,9 +249,13 @@ ol.geom.GeometryCollection.prototype.rotate = function(angle, anchor) {
  * @api
  */
 ol.geom.GeometryCollection.prototype.scale = function(sx, opt_sy, opt_anchor) {
+  var anchor = opt_anchor;
+  if (!anchor) {
+    anchor = ol.extent.getCenter(this.getExtent());
+  }
   var geometries = this.geometries_;
   for (var i = 0, ii = geometries.length; i < ii; ++i) {
-    geometries[i].scale(sx, opt_sy, opt_anchor);
+    geometries[i].scale(sx, opt_sy, anchor);
   }
   this.changed();
 };

test/spec/ol/geom/geometrycollection.test.js

@@ -170,6 +170,43 @@ describe('ol.geom.GeometryCollection', function() {
 
   });
 
+  describe('#scale()', function() {
+
+    it('scales a collection', function() {
+      var geom = new ol.geom.GeometryCollection([
+        new ol.geom.Point([-1, -2]),
+        new ol.geom.LineString([[0, 0], [1, 2]])
+      ]);
+      geom.scale(10);
+      var geometries = geom.getGeometries();
+      expect(geometries[0].getCoordinates()).to.eql([-10, -20]);
+      expect(geometries[1].getCoordinates()).to.eql([[0, 0], [10, 20]]);
+    });
+
+    it('accepts sx and sy', function() {
+      var geom = new ol.geom.GeometryCollection([
+        new ol.geom.Point([-1, -2]),
+        new ol.geom.LineString([[0, 0], [1, 2]])
+      ]);
+      geom.scale(2, 3);
+      var geometries = geom.getGeometries();
+      expect(geometries[0].getCoordinates()).to.eql([-2, -6]);
+      expect(geometries[1].getCoordinates()).to.eql([[0, 0], [2, 6]]);
+    });
+
+    it('accepts an anchor', function() {
+      var geom = new ol.geom.GeometryCollection([
+        new ol.geom.Point([-1, -2]),
+        new ol.geom.LineString([[0, 0], [1, 2]])
+      ]);
+      geom.scale(10, 15, [-1, -2]);
+      var geometries = geom.getGeometries();
+      expect(geometries[0].getCoordinates()).to.eql([-1, -2]);
+      expect(geometries[1].getCoordinates()).to.eql([[9, 28], [19, 58]]);
+    });
+
+  });
+
   describe('#transform()', function() {
 
     var line, multi, point;

test/spec/ol/geom/multipolygon.test.js

@@ -55,6 +55,37 @@ describe('ol.geom.MultiPolygon', function() {
 
   });
 
+  describe('#scale()', function() {
+
+    it('scales a multi-polygon', function() {
+      var geom = new ol.geom.MultiPolygon([[
+        [[-1, -2], [1, -2], [1, 2], [-1, 2], [-1, -2]]
+      ]]);
+      geom.scale(10);
+      var coordinates = geom.getCoordinates();
+      expect(coordinates).to.eql([[[[-10, -20], [10, -20], [10, 20], [-10, 20], [-10, -20]]]]);
+    });
+
+    it('accepts sx and sy', function() {
+      var geom = new ol.geom.MultiPolygon([[
+        [[-1, -2], [1, -2], [1, 2], [-1, 2], [-1, -2]]
+      ]]);
+      geom.scale(2, 3);
+      var coordinates = geom.getCoordinates();
+      expect(coordinates).to.eql([[[[-2, -6], [2, -6], [2, 6], [-2, 6], [-2, -6]]]]);
+    });
+
+    it('accepts an anchor', function() {
+      var geom = new ol.geom.MultiPolygon([[
+        [[-1, -2], [1, -2], [1, 2], [-1, 2], [-1, -2]]
+      ]]);
+      geom.scale(3, 2, [-1, -2]);
+      var coordinates = geom.getCoordinates();
+      expect(coordinates).to.eql([[[[-1, -2], [5, -2], [5, 6], [-1, 6], [-1, -2]]]]);
+    });
+
+  });
+
   describe('with a simple MultiPolygon', function() {
 
     var multiPolygon;

test/spec/ol/geom/polygon.test.js

@@ -505,6 +505,37 @@ describe('ol.geom.Polygon', function() {
     });
   });
 
+  describe('#scale()', function() {
+
+    it('scales a polygon', function() {
+      var geom = new ol.geom.Polygon([
+        [[-1, -2], [1, -2], [1, 2], [-1, 2], [-1, -2]]
+      ]);
+      geom.scale(10);
+      var coordinates = geom.getCoordinates();
+      expect(coordinates).to.eql([[[-10, -20], [10, -20], [10, 20], [-10, 20], [-10, -20]]]);
+    });
+
+    it('accepts sx and sy', function() {
+      var geom = new ol.geom.Polygon([
+        [[-1, -2], [1, -2], [1, 2], [-1, 2], [-1, -2]]
+      ]);
+      geom.scale(2, 3);
+      var coordinates = geom.getCoordinates();
+      expect(coordinates).to.eql([[[-2, -6], [2, -6], [2, 6], [-2, 6], [-2, -6]]]);
+    });
+
+    it('accepts an anchor', function() {
+      var geom = new ol.geom.Polygon([
+        [[-1, -2], [1, -2], [1, 2], [-1, 2], [-1, -2]]
+      ]);
+      geom.scale(3, 2, [-1, -2]);
+      var coordinates = geom.getCoordinates();
+      expect(coordinates).to.eql([[[-1, -2], [5, -2], [5, 6], [-1, 6], [-1, -2]]]);
+    });
+
+  });
+
   describe('ol.geom.Polygon.fromExtent', function() {
     it('creates the correct polygon', function() {
       var extent = [1, 2, 3, 5];