From b6df3d871bf43a23036b7df661f96043988416e7 Mon Sep 17 00:00:00 2001
From: ahocevar <andreas.hocevar@gmail.com>
Date: Wed, 7 Dec 2011 15:55:22 +0100
Subject: [PATCH] It turns out we really want to retile sometimes.

The reason is that we want to avoid moveGriddedTiles to run through hundreds of cycles to shift tiles until we reach the new bounds. But containsBounds does not work if extents that cross the date line start on different worlds, so we use intersectsBounds where we can pass the world bounds to handle this case.
---
 lib/OpenLayers/Layer/Grid.js | 12 ++++++++++++
 tests/Layer/Grid.html        | 10 +++++++++-
 2 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/lib/OpenLayers/Layer/Grid.js b/lib/OpenLayers/Layer/Grid.js
index 3379813d9a..6517b1b1a2 100644
--- a/lib/OpenLayers/Layer/Grid.js
+++ b/lib/OpenLayers/Layer/Grid.js
@@ -319,6 +319,18 @@ OpenLayers.Layer.Grid = OpenLayers.Class(OpenLayers.Layer.HTTPRequest, {
                 }
             } else {
 
+                // if the bounds have changed such that they are not even 
+                // *partially* contained by our tiles (e.g. when user has 
+                // programmatically panned to the other side of the earth on
+                // zoom level 18), then moveGriddedTime could potentially have
+                // to run through thousands of cycles, so we want to reTile
+                // instead (thus, partial true).  
+                forceReTile = forceReTile ||
+                    !tilesBounds.intersectsBounds(bounds, {
+                        worldBounds: this.map.baseLayer.wrapDateLine &&
+                            this.map.getMaxExtent()
+                    });
+
                 if(resolution !== serverResolution) {
                     bounds = this.map.calculateBounds(null, serverResolution);
                     if(forceReTile) {
diff --git a/tests/Layer/Grid.html b/tests/Layer/Grid.html
index 462a04560f..0c5c747559 100644
--- a/tests/Layer/Grid.html
+++ b/tests/Layer/Grid.html
@@ -169,7 +169,7 @@
     
     function test_Layer_Grid_moveTo(t) {
 
-    t.plan(12);
+    t.plan(14);
 
         var map = new OpenLayers.Map('map');
         layer = new OpenLayers.Layer.WMS(name, url, params);
@@ -300,6 +300,14 @@
             t.ok(g_WhichFunc == "MoveGridded", "if tiles not drastically out of bounds, we call moveGriddedTile()");
             t.ok(g_Bounds.equals(b), "if tiles not drastically out of bounds, we call moveGriddedTile() with correct bounds");
         });
+
+        // drastic pan
+        clearTestBounds();
+        tilesBounds = new OpenLayers.Bounds(-150,-150,-120,-120);
+        layer.moveTo(null, zoomChanged);
+        t.ok(g_WhichFunc == "InitGridded", "if tiles drastically out of bounds, we call initGriddedTile()");
+        t.ok(g_Bounds.equals(b), "if tiles drastically out of bounds, we call initGriddedTile() with correct bounds");
+
     }
 
     /** THIS WOULD BE WHERE THE TESTS WOULD GO FOR