EncodedPolyline: Extracted universal decode(encoded, dims) method

lib/OpenLayers/Format/EncodedPolyline.js

@@ -61,11 +61,50 @@ OpenLayers.Format.EncodedPolyline = OpenLayers.Class(OpenLayers.Format, {
         else if (this.geometryType != "polygon")
             return null;
 
+        var points = this.decode(encoded, 2);
+        var pointGeometries = new Array();
+        for (i in points) {
+            var point = points[i];
+            pointGeometries.push(
+                new OpenLayers.Geometry.Point(point[1] * 1e-5, point[0] * 1e-5)
+            );
+        }
+
+        if (this.geometryType == "polygon")
+            return new OpenLayers.Feature.Vector(
+                new OpenLayers.Geometry.Polygon([
+                    new OpenLayers.Geometry.LinearRing(pointGeometries)
+                ])
+            );
+
+        return new OpenLayers.Feature.Vector(
+            new geomType(pointGeometries)
+        );
+    },
+
+    /**
+     * Method: decode
+     * Deserialize an encoded string and return an array of n-dimensional
+     * points.
+     *
+     * Parameters:
+     * encoded - {String} An encoded string
+     * dims - {int} The dimension of the points that are returned
+     *
+     * Returns:
+     * {Array(Array(int))} An array containing n-dimensional arrays of
+     *     coordinates.
+     */
+    decode: function(encoded, dims) {
         var points = new Array();
-        var point = new Array(0, 0);
+        var point = new Array(dims);
+
+        // Reset the point array
+        for (var i = 0; i < point.length; ++i)
+            point[i] = 0;
 
         for (var i = 0; i < encoded.length;) {
-            for (var dim = 0; dim < 2; ++dim) {
+            for (var dim = 0; dim < dims; ++dim) {
                 var result = 0;
                 var shift = 0;
 
@@ -79,20 +118,10 @@ OpenLayers.Format.EncodedPolyline = OpenLayers.Class(OpenLayers.Format, {
                 point[dim] += ((result & 1) ? ~(result >> 1) : (result >> 1));
             }
 
-            points.push(new OpenLayers.Geometry.Point(point[1] * 1e-5,
+            points.push(point.slice(0));
-                                                      point[0] * 1e-5));
         }
 
-        if (this.geometryType == "polygon")
+        return points;
-            return new OpenLayers.Feature.Vector(
-                new OpenLayers.Geometry.Polygon([
-                    new OpenLayers.Geometry.LinearRing(points)
-                ])
-            );
-
-        return new OpenLayers.Feature.Vector(
-            new geomType(points)
-        );
     },
 
     CLASS_NAME: "OpenLayers.Format.EncodedPolyline"

tests/Format/EncodedPolyline.html

@@ -3,10 +3,19 @@
     <script src="../OLLoader.js"></script>
     <script type="text/javascript">
 
+    var basePoints = new Array(
+        new Array(3850000, -12020000),
+        new Array(4070000, -12095000),
+        new Array(4325200, -12645300)
+    );
+
     var points = [
-        new OpenLayers.Geometry.Point(-120.2, 38.5),
+        new OpenLayers.Geometry.Point(basePoints[0][1] * 1e-5,
-        new OpenLayers.Geometry.Point(-120.95, 40.7),
+                                      basePoints[0][0] * 1e-5),
-        new OpenLayers.Geometry.Point(-126.45300000000002, 43.252)
+        new OpenLayers.Geometry.Point(basePoints[1][1] * 1e-5,
+                                      basePoints[1][0] * 1e-5),
+        new OpenLayers.Geometry.Point(basePoints[2][1] * 1e-5,
+                                      basePoints[2][0] * 1e-5)
     ];
 
     var linestring = new OpenLayers.Feature.Vector(
@@ -45,6 +54,7 @@
         t.plan(4);
 
         var format = new OpenLayers.Format.EncodedPolyline();
+
         t.ok(linestring.geometry.equals(format.read(encoded).geometry),
              "format correctly reads encoded polyline");
 
@@ -63,6 +73,20 @@
              "format correctly reads encoded polygon");
     }
 
+    function test_Format_EncodedPolyline_decode(t) {
+        t.plan(6);
+
+        var format = new OpenLayers.Format.EncodedPolyline();
+
+        var decodedPoints = format.decode(encoded, 2);
+        for (i in decodedPoints) {
+            var point = basePoints[i];
+            var decodedPoint = decodedPoints[i];
+            t.eq(point[0], decodedPoint[0]);
+            t.eq(point[1], decodedPoint[1]);
+        }
+    }
+
     </script>
 </head>
 <body>