Merge pull request #2313 from tschaub/transform-extent

Add ol.proj.transformExtent function.

src/ol/proj/proj.js

@@ -10,6 +10,7 @@ goog.require('goog.object');
 goog.require('ol');
 goog.require('ol.Extent');
 goog.require('ol.TransformFunction');
+goog.require('ol.extent');
 goog.require('ol.sphere.NORMAL');
 
 
@@ -700,9 +701,11 @@ ol.proj.cloneTransform = function(input, opt_output, opt_dimension) {
 
 /**
  * Transforms a coordinate from source projection to destination projection.
- * See {@link ol.extent.applyTransform} for extent transformation.
+ * This returns a new coordinate (and does not modify the original).
- * See the applyTransform method of {@link ol.geom.SimpleGeometry} and its
+ *
- * subclasses for geometry transforms.
+ * See {@link ol.proj.transformExtent} for extent transformation.
+ * See the transform method of {@link ol.geom.Geometry} and its subclasses for
+ * geometry transforms.
  *
  * @param {ol.Coordinate} coordinate Coordinate.
  * @param {ol.proj.ProjectionLike} source Source projection-like.
@@ -716,6 +719,22 @@ ol.proj.transform = function(coordinate, source, destination) {
 };
 
 
+/**
+ * Transforms an extent from source projection to destination projection.  This
+ * returns a new extent (and does not modify the original).
+ *
+ * @param {ol.Extent} extent The extent to transform.
+ * @param {ol.proj.ProjectionLike} source Source projection-like.
+ * @param {ol.proj.ProjectionLike} destination Destination projection-like.
+ * @return {ol.Extent} The transformed extent.
+ * @api
+ */
+ol.proj.transformExtent = function(extent, source, destination) {
+  var transformFn = ol.proj.getTransform(source, destination);
+  return ol.extent.applyTransform(extent, transformFn);
+};
+
+
 /**
  * Transforms the given point to the destination projection.
  *

test/spec/ol/proj/proj.test.js

@@ -101,6 +101,23 @@ describe('ol.proj', function() {
     });
   });
 
+  describe('transformExtent()', function() {
+
+    it('transforms an extent given projection identifiers', function() {
+      var sourceExtent = [-15, -30, 45, 60];
+      var destinationExtent = ol.proj.transformExtent(
+          sourceExtent, 'EPSG:4326', 'EPSG:3857');
+      expect(destinationExtent).not.to.be(undefined);
+      expect(destinationExtent).not.to.be(null);
+      expect(destinationExtent[0])
+          .to.roughlyEqual(-1669792.3618991037, 1e-9);
+      expect(destinationExtent[2]).to.roughlyEqual(5009377.085697311, 1e-9);
+      expect(destinationExtent[1]).to.roughlyEqual(-3503549.843504376, 1e-8);
+      expect(destinationExtent[3]).to.roughlyEqual(8399737.889818361, 1e-8);
+    });
+
+  });
+
   describe('Proj4js integration', function() {
 
     it('allows Proj4js projections to be used transparently', function() {