Merge pull request #348 from bartvde/getcentroid

getCentroid should just return the first point if a linear ring only has less than three components (r=@tschaub)

lib/OpenLayers/Geometry/LinearRing.js

@@ -191,7 +191,11 @@ OpenLayers.Geometry.LinearRing = OpenLayers.Class(
      * {<OpenLayers.Geometry.Point>} The centroid of the collection
      */
     getCentroid: function() {
-        if (this.components && (this.components.length > 2)) {
+        if (this.components) {
+            var len = this.components.length;
+            if (len > 0 && len <= 2) {
+                return this.components[0].clone();
+            } else if (len > 2) {
                 var sumX = 0.0;
                 var sumY = 0.0;
                 for (var i = 0; i < this.components.length - 1; i++) {
@@ -207,6 +211,7 @@ OpenLayers.Geometry.LinearRing = OpenLayers.Class(
             } else {
                 return null;
             }
+        }
     },
 
     /**

tests/Geometry/Polygon.html

@@ -386,6 +386,20 @@
         
     }
 
+    function testGetCentroid(t) {
+        t.plan(4);
+        var bounds = new OpenLayers.Bounds(5, 10, 5, 10);
+        var geometry = bounds.toGeometry();
+        var centroid = geometry.getCentroid();
+        t.eq(geometry.components[0].components.length, 2, "only two vertices since the box has left=right and bottom=top");
+        t.ok(centroid && centroid.x === 5 && centroid.y === 10, "getCentroid returns a point geometry even if the ring of the polygon has only 2 vertices");
+        bounds = new OpenLayers.Bounds(0, 0, 10, 10);
+        geometry = bounds.toGeometry();
+        centroid = geometry.getCentroid();
+        t.eq(geometry.components[0].components.length, 5, "five vertices expected");
+        t.ok(centroid && centroid.x === 5 && centroid.y === 5, "getCentroid returns the correct point geometry");
+    }
+    
 
   </script>
 </head>