From 7a7ea8a0720fe4bd5bd9b69b09433198a4672a64 Mon Sep 17 00:00:00 2001
From: Tom Payne <twpayne@gmail.com>
Date: Mon, 8 Apr 2013 21:15:53 +0200
Subject: [PATCH] Add ol.tilegrid.TileGrid.getTileCoordChildTileRange

---
 src/ol/tilegrid/tilegrid.js | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/src/ol/tilegrid/tilegrid.js b/src/ol/tilegrid/tilegrid.js
index 3952497768..074430cdd4 100644
--- a/src/ol/tilegrid/tilegrid.js
+++ b/src/ol/tilegrid/tilegrid.js
@@ -164,6 +164,21 @@ ol.tilegrid.TileGrid.prototype.getResolutions = function() {
 };
 
 
+/**
+ * @param {ol.TileCoord} tileCoord Tile coordinate.
+ * @return {ol.TileRange} Tile range.
+ */
+ol.tilegrid.TileGrid.prototype.getTileCoordChildTileRange =
+    function(tileCoord) {
+  if (tileCoord.z < this.resolutions_.length) {
+    var tileCoordExtent = this.getTileCoordExtent(tileCoord);
+    return this.getTileRangeForExtentAndZ(tileCoordExtent, tileCoord.z + 1);
+  } else {
+    return null;
+  }
+};
+
+
 /**
  * @param {number} z Z.
  * @param {ol.TileRange} tileRange Tile range.