From 97d2eaa746febfc70224a94f42cbb751102a8158 Mon Sep 17 00:00:00 2001
From: Remo Laubacher <remo.laubacher@gmail.com>
Date: Tue, 15 Dec 2015 13:14:10 +0100
Subject: [PATCH 1/2] ignore hidden markers in cluster

---
 src/markerclusterer.js | 27 +++++++++++++++++++++++----
 1 file changed, 23 insertions(+), 4 deletions(-)

diff --git a/src/markerclusterer.js b/src/markerclusterer.js
index a31e3a9..1398437 100755
--- a/src/markerclusterer.js
+++ b/src/markerclusterer.js
@@ -859,7 +859,7 @@ Cluster.prototype.addMarker = function(marker) {
   marker.isAdded = true;
   this.markers_.push(marker);
 
-  var len = this.markers_.length;
+  var len = this.getVisibleMarkers().length;
   if (len < this.minClusterSize_ && marker.getMap() != this.map_) {
     // Min cluster size not reached so show the marker.
     marker.setMap(this.map_);
@@ -936,6 +936,23 @@ Cluster.prototype.getMarkers = function() {
 };
 
 
+/**
+ *  Returns the array of markers in the cluster.
+ *
+ *  @return {Array.<google.maps.Marker>} The markers.
+ */
+Cluster.prototype.getVisibleMarkers = function() {
+  var visibleMarkers = [];
+  for (var i in this.markers_) {
+    var marker = this.markers_[i];
+    if (marker.visible) {
+      visibleMarkers.push(marker);
+    }
+  }
+  return visibleMarkers;
+};
+
+
 /**
  * Returns the center of the cluster.
  *
@@ -984,23 +1001,24 @@ Cluster.prototype.getMap = function() {
 Cluster.prototype.updateIcon = function() {
   var zoom = this.map_.getZoom();
   var mz = this.markerClusterer_.getMaxZoom();
+  var markers = this.getVisibleMarkers();
 
   if (mz && zoom > mz) {
     // The zoom is greater than our max zoom so show all the markers in cluster.
-    for (var i = 0, marker; marker = this.markers_[i]; i++) {
+    for (var i = 0, marker; marker = markers[i]; i++) {
       marker.setMap(this.map_);
     }
     return;
   }
 
-  if (this.markers_.length < this.minClusterSize_) {
+  if (markers_.length < this.minClusterSize_) {
     // Min cluster size not yet reached.
     this.clusterIcon_.hide();
     return;
   }
 
   var numStyles = this.markerClusterer_.getStyles().length;
-  var sums = this.markerClusterer_.getCalculator()(this.markers_, numStyles);
+  var sums = this.markerClusterer_.getCalculator()(markers, numStyles);
   this.clusterIcon_.setCenter(this.center_);
   this.clusterIcon_.setSums(sums);
   this.clusterIcon_.show();
@@ -1298,6 +1316,7 @@ MarkerClusterer.prototype['draw'] = MarkerClusterer.prototype.draw;
 Cluster.prototype['getCenter'] = Cluster.prototype.getCenter;
 Cluster.prototype['getSize'] = Cluster.prototype.getSize;
 Cluster.prototype['getMarkers'] = Cluster.prototype.getMarkers;
+Cluster.prototype['getVisibleMarkers'] = Cluster.prototype.getVisibleMarkers;
 
 ClusterIcon.prototype['onAdd'] = ClusterIcon.prototype.onAdd;
 ClusterIcon.prototype['draw'] = ClusterIcon.prototype.draw;

From a52aa4a721bd58db4ae0c0e88320428c31ffdb83 Mon Sep 17 00:00:00 2001
From: Remo Laubacher <remo.laubacher@gmail.com>
Date: Tue, 15 Dec 2015 13:19:00 +0100
Subject: [PATCH 2/2] hide correct marker

---
 src/markerclusterer.js | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/src/markerclusterer.js b/src/markerclusterer.js
index 1398437..ebf218c 100755
--- a/src/markerclusterer.js
+++ b/src/markerclusterer.js
@@ -859,7 +859,8 @@ Cluster.prototype.addMarker = function(marker) {
   marker.isAdded = true;
   this.markers_.push(marker);
 
-  var len = this.getVisibleMarkers().length;
+  var visibleMarkers = this.getVisibleMarkers();
+  var len = visibleMarkers.length;
   if (len < this.minClusterSize_ && marker.getMap() != this.map_) {
     // Min cluster size not reached so show the marker.
     marker.setMap(this.map_);
@@ -868,7 +869,7 @@ Cluster.prototype.addMarker = function(marker) {
   if (len == this.minClusterSize_) {
     // Hide the markers that were showing.
     for (var i = 0; i < len; i++) {
-      this.markers_[i].setMap(null);
+      visibleMarkers[i].setMap(null);
     }
   }