From c4f9704f4f42d5d4af30a816db32210e13f5c3d6 Mon Sep 17 00:00:00 2001
From: Tom Payne <twpayne@gmail.com>
Date: Thu, 26 Jul 2012 01:37:22 +0200
Subject: [PATCH] Add ol.TileUrlFunction.nullTileUrlFunction

---
 src/ol/tile/tileurlfunction.js | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/src/ol/tile/tileurlfunction.js b/src/ol/tile/tileurlfunction.js
index 38ef5179b9..6e8c29c6c0 100644
--- a/src/ol/tile/tileurlfunction.js
+++ b/src/ol/tile/tileurlfunction.js
@@ -54,6 +54,15 @@ ol.TileUrlFunction.createFromTemplates = function(templates) {
 };
 
 
+/**
+ * @param {ol.TileCoord} tileCoord Tile coordinate.
+ * @return {string|undefined} Tile URL.
+ */
+ol.TileUrlFunction.nullTileUrlFunction = function(tileCoord) {
+  return undefined;
+};
+
+
 /**
  * @param {function(ol.TileCoord): ol.TileCoord} transform Transform.
  * @param {ol.TileUrlFunctionType} tileUrlFunction Tile URL function.