Maintain M and Z coordinates in ol.geom.Circle#getClosestPoint

src/ol/geom/circle.js

@@ -39,21 +39,24 @@ ol.geom.Circle.prototype.clone = function() {
 ol.geom.Circle.prototype.closestPointXY =
     function(x, y, closestPoint, minSquaredDistance) {
   var flatCoordinates = this.flatCoordinates;
-  var radius = flatCoordinates[this.stride] - flatCoordinates[0];
   var dx = x - flatCoordinates[0];
   var dy = y - flatCoordinates[1];
-  var d = Math.sqrt(dx * dx + dy * dy);
+  var squaredDistance = dx * dx + dy * dy;
-  var distance = Math.max(d, 0);
-  var squaredDistance = distance * distance;
   if (squaredDistance < minSquaredDistance) {
-    if (d === 0) {
+    var i;
-      closestPoint[0] = flatCoordinates[0];
+    if (squaredDistance === 0) {
-      closestPoint[1] = flatCoordinates[1];
+      for (i = 0; i < this.stride; ++i) {
+        closestPoint[i] = flatCoordinates[i];
+      }
     } else {
-      var delta = radius / d;
+      var delta = this.getRadius() / Math.sqrt(squaredDistance);
       closestPoint[0] = flatCoordinates[0] + delta * dx;
       closestPoint[1] = flatCoordinates[1] + delta * dy;
+      for (i = 2; i < this.stride; ++i) {
+        closestPoint[i] = flatCoordinates[i];
+      }
     }
+    closestPoint.length = this.stride;
     return squaredDistance;
   } else {
     return minSquaredDistance;

test/spec/ol/geom/circle.test.js

@@ -89,6 +89,37 @@ describe('ol.geom.Circle', function() {
         expect(closestPoint[1]).to.roughlyEqual(-Math.sqrt(0.5), 1e-15);
       });
 
+      it('maintains Z coordinates', function() {
+        var circle = new ol.geom.Circle([0, 0, 1], 1);
+        expect(circle.getLayout()).to.be(ol.geom.GeometryLayout.XYZ);
+        var closestPoint = circle.getClosestPoint([2, 0]);
+        expect(closestPoint).to.have.length(3);
+        expect(closestPoint[0]).to.roughlyEqual(1, 1e-15);
+        expect(closestPoint[1]).to.roughlyEqual(0, 1e-15);
+        expect(closestPoint[2]).to.be(1);
+      });
+
+      it('maintains M coordinates', function() {
+        var circle = new ol.geom.Circle([0, 0, 2], 1,
+            ol.geom.GeometryLayout.XYM);
+        var closestPoint = circle.getClosestPoint([2, 0]);
+        expect(closestPoint).to.have.length(3);
+        expect(closestPoint[0]).to.roughlyEqual(1, 1e-15);
+        expect(closestPoint[1]).to.roughlyEqual(0, 1e-15);
+        expect(closestPoint[2]).to.be(2);
+      });
+
+      it('maintains Z and M coordinates', function() {
+        var circle = new ol.geom.Circle([0, 0, 1, 2], 1);
+        expect(circle.getLayout()).to.be(ol.geom.GeometryLayout.XYZM);
+        var closestPoint = circle.getClosestPoint([2, 0]);
+        expect(closestPoint).to.have.length(4);
+        expect(closestPoint[0]).to.roughlyEqual(1, 1e-15);
+        expect(closestPoint[1]).to.roughlyEqual(0, 1e-15);
+        expect(closestPoint[2]).to.be(1);
+        expect(closestPoint[3]).to.be(2);
+      });
+
     });
 
     describe('#getExtent', function() {