From 05ceaab6207d6384328043b8e963ea646b8a0c4f Mon Sep 17 00:00:00 2001
From: Frederic Junod <frederic.junod@camptocamp.com>
Date: Tue, 12 Apr 2016 11:43:46 +0200
Subject: [PATCH] Add an optional feature filter to
 getClosestFeatureToCoordinate

---
 src/ol/source/vectorsource.js            | 42 ++++++++++++++----------
 test/spec/ol/source/vectorsource.test.js | 32 ++++++++++++++++++
 2 files changed, 56 insertions(+), 18 deletions(-)

diff --git a/src/ol/source/vectorsource.js b/src/ol/source/vectorsource.js
index b00d7acefa..14b74263df 100644
--- a/src/ol/source/vectorsource.js
+++ b/src/ol/source/vectorsource.js
@@ -612,10 +612,13 @@ ol.source.Vector.prototype.getFeaturesInExtent = function(extent) {
  * This method is not available when the source is configured with
  * `useSpatialIndex` set to `false`.
  * @param {ol.Coordinate} coordinate Coordinate.
+ * @param {function(ol.Feature):boolean=} opt_filter Feature filter function.
+ *     The filter function will receive one argument, the {@link ol.Feature feature}
+ *     and it should return a boolean value. By default, no filtering is made.
  * @return {ol.Feature} Closest feature.
  * @api stable
  */
-ol.source.Vector.prototype.getClosestFeatureToCoordinate = function(coordinate) {
+ol.source.Vector.prototype.getClosestFeatureToCoordinate = function(coordinate, opt_filter) {
   // Find the closest feature using branch and bound.  We start searching an
   // infinite extent, and find the distance from the first feature found.  This
   // becomes the closest feature.  We then compute a smaller extent which any
@@ -632,28 +635,31 @@ ol.source.Vector.prototype.getClosestFeatureToCoordinate = function(coordinate)
   goog.asserts.assert(this.featuresRtree_,
       'getClosestFeatureToCoordinate does not work with useSpatialIndex set ' +
       'to false');
+  var filter = opt_filter ? opt_filter : ol.functions.TRUE;
   this.featuresRtree_.forEachInExtent(extent,
       /**
        * @param {ol.Feature} feature Feature.
        */
       function(feature) {
-        var geometry = feature.getGeometry();
-        goog.asserts.assert(geometry,
-            'feature geometry is defined and not null');
-        var previousMinSquaredDistance = minSquaredDistance;
-        minSquaredDistance = geometry.closestPointXY(
-            x, y, closestPoint, minSquaredDistance);
-        if (minSquaredDistance < previousMinSquaredDistance) {
-          closestFeature = feature;
-          // This is sneaky.  Reduce the extent that it is currently being
-          // searched while the R-Tree traversal using this same extent object
-          // is still in progress.  This is safe because the new extent is
-          // strictly contained by the old extent.
-          var minDistance = Math.sqrt(minSquaredDistance);
-          extent[0] = x - minDistance;
-          extent[1] = y - minDistance;
-          extent[2] = x + minDistance;
-          extent[3] = y + minDistance;
+        if (filter(feature)) {
+          var geometry = feature.getGeometry();
+          goog.asserts.assert(geometry,
+              'feature geometry is defined and not null');
+          var previousMinSquaredDistance = minSquaredDistance;
+          minSquaredDistance = geometry.closestPointXY(
+              x, y, closestPoint, minSquaredDistance);
+          if (minSquaredDistance < previousMinSquaredDistance) {
+            closestFeature = feature;
+            // This is sneaky.  Reduce the extent that it is currently being
+            // searched while the R-Tree traversal using this same extent object
+            // is still in progress.  This is safe because the new extent is
+            // strictly contained by the old extent.
+            var minDistance = Math.sqrt(minSquaredDistance);
+            extent[0] = x - minDistance;
+            extent[1] = y - minDistance;
+            extent[2] = x + minDistance;
+            extent[3] = y + minDistance;
+          }
         }
       });
   return closestFeature;
diff --git a/test/spec/ol/source/vectorsource.test.js b/test/spec/ol/source/vectorsource.test.js
index 1ec4667cbc..46dfaebbc2 100644
--- a/test/spec/ol/source/vectorsource.test.js
+++ b/test/spec/ol/source/vectorsource.test.js
@@ -77,6 +77,37 @@ describe('ol.source.Vector', function() {
 
   });
 
+  describe('when populated with 3 features', function() {
+
+    var features = [];
+    var vectorSource;
+    beforeEach(function() {
+      features.push(new ol.Feature(new ol.geom.LineString([[0, 0], [10, 10]])));
+      features.push(new ol.Feature(new ol.geom.Point([0, 10])));
+      features.push(new ol.Feature(new ol.geom.Point([10, 5])));
+      vectorSource = new ol.source.Vector({
+        features: features
+      });
+    });
+
+    describe('#getClosestFeatureToCoordinate', function() {
+
+      it('returns the expected feature', function() {
+        var feature = vectorSource.getClosestFeatureToCoordinate([1, 9]);
+        expect(feature).to.be(features[1]);
+      });
+
+      it('returns the expected feature when a filter is used', function() {
+        var feature = vectorSource.getClosestFeatureToCoordinate([1, 9], function(feature) {
+          return feature.getGeometry().getType() == 'LineString';
+        });
+        expect(feature).to.be(features[0]);
+      });
+
+    });
+
+  });
+
   describe('when populated with 10 random points and a null', function() {
 
     var features;
@@ -558,5 +589,6 @@ goog.require('ol.events');
 goog.require('ol.Collection');
 goog.require('ol.Feature');
 goog.require('ol.geom.Point');
+goog.require('ol.geom.LineString');
 goog.require('ol.proj');
 goog.require('ol.source.Vector');