Make transform functions work with arrays

Instead of working with ol.Coordinate instances, transform functions work with arrays.  This is in anticipation of using transform functions to transform large arrays of vertex coordinate values.  The ol.projection.transform and ol.projection.transformWithCodes are slightly more convenient functions for dealing with ol.Coordinate instances.  Whether we make this more consistent with the use of functions returned by ol.projection.getTransform is up for discussion.

src/ol/projection.js

@@ -397,14 +397,29 @@ ol.projection.getTransform = function(source, destination) {
     var destinationProj4jsProj = proj4jsDestination.getProj4jsProj();
     transform =
         /**
-         * @param {ol.Coordinate} coordinate Coordinate.
-         * @return {ol.Coordinate} Coordinate.
+         * @param {Array.<number>} input Input coordinate values.
+         * @param {number=} opt_dimension Dimension.
+         * @return {Array.<number>} Output coordinate values.
          */
-        function(coordinate) {
-      var proj4jsPoint = new Proj4js.Point(coordinate.x, coordinate.y);
-      proj4jsPoint = Proj4js.transform(
-          sourceProj4jsProj, destinationProj4jsProj, proj4jsPoint);
-      return new ol.Coordinate(proj4jsPoint.x, proj4jsPoint.y);
+        function(input, opt_dimension) {
+      var length = input.length,
+          dimension = goog.isDef(opt_dimension) ? opt_dimension : 2,
+          output, proj4jsPoint;
+      if (dimension > 2) {
+        // preserve values beyond second dimension
+        output = input.slice();
+      } else {
+        output = new Array(length);
+      }
+      goog.asserts.assert(output.length % dimension === 0);
+      for (var i = 0; i < length; i += dimension) {
+        proj4jsPoint = new Proj4js.Point(input[i], input[i + 1]);
+        proj4jsPoint = Proj4js.transform(
+            sourceProj4jsProj, destinationProj4jsProj, proj4jsPoint);
+        output[i] = proj4jsPoint.x;
+        output[i + 1] = proj4jsPoint.y;
+      }
+      return output;
     };
     ol.projection.addTransform(source, destination, transform);
   }
@@ -418,7 +433,7 @@ ol.projection.getTransform = function(source, destination) {
 
 /**
  * Given the projection codes this method searches for a transformation function
- * to convert coordinate from the source projection to the destination
+ * to convert a coordinates array from the source projection to the destination
  * projection.
  *
  * @param {string} sourceCode Source code.
@@ -433,20 +448,23 @@ ol.projection.getTransformFromCodes = function(sourceCode, destinationCode) {
 
 
 /**
- * @param {ol.Coordinate} point Point.
- * @return {ol.Coordinate} Unaltered point (same reference).
+ * @param {Array.<number>} input Input coordinate array.
+ * @param {number=} opt_dimension Dimension.
+ * @return {Array.<number>} Input coordinate array (same array as input).
  */
-ol.projection.identityTransform = function(point) {
-  return point;
+ol.projection.identityTransform = function(input, opt_dimension) {
+  return input;
 };
 
 
 /**
- * @param {ol.Coordinate} point Point.
- * @return {ol.Coordinate} Equal point (different reference).
+ * @param {Array.<number>} input Input coordinate array.
+ * @param {number=} opt_dimension Dimension.
+ * @return {Array.<number>} Output coordinate array (new array, same coordinate
+ *     values).
  */
-ol.projection.cloneTransform = function(point) {
-  return new ol.Coordinate(point.x, point.y);
+ol.projection.cloneTransform = function(input, opt_dimension) {
+  return input.slice();
 };
 
 
@@ -460,7 +478,8 @@ ol.projection.cloneTransform = function(point) {
  */
 ol.projection.transform = function(point, source, destination) {
   var transformFn = ol.projection.getTransform(source, destination);
-  return transformFn(point);
+  var output = transformFn([point.x, point.y]);
+  return new ol.Coordinate(output[0], output[1]);
 };
 
 
@@ -474,5 +493,6 @@ ol.projection.transformWithCodes =
     function(point, sourceCode, destinationCode) {
   var transformFn = ol.projection.getTransformFromCodes(
       sourceCode, destinationCode);
-  return transformFn(point);
+  var output = transformFn([point.x, point.y]);
+  return new ol.Coordinate(output[0], output[1]);
 };