Change event for polygons

src/ol/geom/polygon.js

@@ -1,9 +1,12 @@
 goog.provide('ol.geom.Polygon');
 
 goog.require('goog.asserts');
+goog.require('goog.events');
+goog.require('goog.events.EventType');
 goog.require('ol.CoordinateArray');
 goog.require('ol.extent');
 goog.require('ol.geom.Geometry');
+goog.require('ol.geom.GeometryEvent');
 goog.require('ol.geom.GeometryType');
 goog.require('ol.geom.LinearRing');
 
@@ -38,7 +41,7 @@ ol.geom.Polygon = function(coordinates) {
    * @private
    */
   this.rings_ = new Array(numRings);
-  var ringCoords;
+  var ringCoords, ring;
   for (var i = 0; i < numRings; ++i) {
     ringCoords = coordinates[i];
     if (i === 0) {
@@ -52,7 +55,10 @@ ol.geom.Polygon = function(coordinates) {
         ringCoords.reverse();
       }
     }
-    this.rings_[i] = new ol.geom.LinearRing(ringCoords);
+    ring = new ol.geom.LinearRing(ringCoords);
+    goog.events.listen(ring, goog.events.EventType.CHANGE,
+        this.handleRingChange_, false, this);
+    this.rings_[i] = ring;
   }
 
 };
@@ -98,6 +104,24 @@ ol.geom.Polygon.prototype.getRings = function() {
 };
 
 
+/**
+ * Listener for ring change events.
+ * @param {ol.geom.GeometryEvent} evt Geometry event.
+ * @private
+ */
+ol.geom.Polygon.prototype.handleRingChange_ = function(evt) {
+  var ring = evt.target;
+  var oldExtent = null;
+  if (ring === this.rings_[0]) {
+    oldExtent = evt.oldExtent;
+  } else {
+    oldExtent = this.getBounds();
+  }
+  this.dispatchEvent(new ol.geom.GeometryEvent(goog.events.EventType.CHANGE,
+      this, oldExtent));
+};
+
+
 /**
  * Check whether a given coordinate is inside this polygon. Note that this is a
  * fast and simple check - points on an edge or vertex of the polygon or one of

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

@@ -132,8 +132,51 @@ describe('ol.geom.Polygon', function() {
 
   });
 
+  describe('change event', function() {
+
+    var outer, inner;
+    beforeEach(function() {
+      outer = [[0, 0], [10, 0], [10, 10], [0, 10], [0, 0]];
+      inner = [[2, 2], [2, 8], [8, 8], [8, 2], [2, 2]];
+    });
+
+    it('is fired when outer ring is modified', function(done) {
+      var poly = new ol.geom.Polygon([outer, inner]);
+      var rings = poly.getRings();
+      var bounds = poly.getBounds();
+      goog.events.listen(poly, 'change', function(evt) {
+        expect(evt.target).to.be(poly);
+        expect(evt.oldExtent).to.eql(bounds);
+        expect(evt.target.getBounds()).to.eql([0, 0, 11, 10]);
+        done();
+      });
+
+      var outerCoords = rings[0].getCoordinates();
+      outerCoords[1][0] = 11;
+      rings[0].setCoordinates(outerCoords);
+    });
+
+    it('is fired when inner ring is modified', function(done) {
+      var poly = new ol.geom.Polygon([outer, inner]);
+      var rings = poly.getRings();
+      var bounds = poly.getBounds();
+      goog.events.listen(poly, 'change', function(evt) {
+        expect(evt.target).to.be(poly);
+        expect(evt.oldExtent).to.eql(bounds);
+        expect(evt.target.getBounds()).to.eql([0, 0, 10, 10]);
+        done();
+      });
+
+      var innerCoords = rings[1].getCoordinates();
+      innerCoords[1][0] = 3;
+      rings[1].setCoordinates(innerCoords);
+    });
+
+  });
+
 });
 
+goog.require('goog.events');
 goog.require('ol.geom.Geometry');
 goog.require('ol.geom.LinearRing');
 goog.require('ol.geom.Polygon');