rounded zoom to work with fractional zoom levels

src/MarkerClusterGroup.js

@@ -720,7 +720,7 @@ L.MarkerClusterGroup = L.FeatureGroup.extend({
 		}
 		this._mergeSplitClusters();
 
-		this._zoom = this._map._zoom;
+		this._zoom = Math.round(this._map._zoom);
 		this._currentShownBounds = this._getExpandedVisibleBounds();
 	},
 
@@ -732,7 +732,7 @@ L.MarkerClusterGroup = L.FeatureGroup.extend({
 		var newBounds = this._getExpandedVisibleBounds();
 
 		this._topClusterLevel._recursivelyRemoveChildrenFromMap(this._currentShownBounds, this._zoom, newBounds);
-		this._topClusterLevel._recursivelyAddChildrenToMap(null, this._map._zoom, newBounds);
+		this._topClusterLevel._recursivelyAddChildrenToMap(null, Math.round(this._map._zoom), newBounds);
 
 		this._currentShownBounds = newBounds;
 		return;
@@ -858,21 +858,22 @@ L.MarkerClusterGroup = L.FeatureGroup.extend({
 
 	//Merge and split any existing clusters that are too big or small
 	_mergeSplitClusters: function () {
+		var mapZoom = Math.round(this._map._zoom);
 
 		//Incase we are starting to split before the animation finished
 		this._processQueue();
 
-		if (this._zoom < this._map._zoom && this._currentShownBounds.contains(this._getExpandedVisibleBounds())) { //Zoom in, split
+		if (this._zoom < mapZoom && this._currentShownBounds.contains(this._getExpandedVisibleBounds())) { //Zoom in, split
 			this._animationStart();
 			//Remove clusters now off screen
 			this._topClusterLevel._recursivelyRemoveChildrenFromMap(this._currentShownBounds, this._zoom, this._getExpandedVisibleBounds());
 
-			this._animationZoomIn(this._zoom, this._map._zoom);
+			this._animationZoomIn(this._zoom, mapZoom);
 
-		} else if (this._zoom > this._map._zoom) { //Zoom out, merge
+		} else if (this._zoom > mapZoom) { //Zoom out, merge
 			this._animationStart();
 
-			this._animationZoomOut(this._zoom, this._map._zoom);
+			this._animationZoomOut(this._zoom, mapZoom);
 		} else {
 			this._moveEnd();
 		}