From be6ecf5dca8f70dcf098df6e407bdb9b94efb6be Mon Sep 17 00:00:00 2001
From: crschmidt <crschmidt@crschmidt.net>
Date: Mon, 22 May 2006 18:11:45 +0000
Subject: [PATCH] Store div offsets in event div object, caching them until a
 updateSize call. This provides a significant performance gain in places where
 the div contains hundreds or thousands of markers, because as the div element
 gets bigger, determining its size through Prototype.element.page() becomes
 slower by a factor of up to 4 (determined through profiling with venkman).

git-svn-id: http://svn.openlayers.org/trunk/openlayers@271 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf
---
 lib/OpenLayers/Events.js | 8 +++++---
 lib/OpenLayers/Map.js    | 2 +-
 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/lib/OpenLayers/Events.js b/lib/OpenLayers/Events.js
index de83e342e8..eefa2fbc02 100644
--- a/lib/OpenLayers/Events.js
+++ b/lib/OpenLayers/Events.js
@@ -72,10 +72,12 @@ OpenLayers.Events.prototype = {
     * @return {OpenLayers.Pixel}
     */
     getMousePosition: function (evt) {
-        var offsets = Position.page(this.div); 
+        if (!this.div.offsets) {
+            this.div.offsets = Position.page(this.div);
+        }
         return new OpenLayers.Pixel(
-                        evt.clientX - offsets[0], 
-                        evt.clientY - offsets[1]); 
+                        evt.clientX - this.div.offsets[0], 
+                        evt.clientY - this.div.offsets[1]); 
     },
 
     /**
diff --git a/lib/OpenLayers/Map.js b/lib/OpenLayers/Map.js
index 920816d8bc..fafe73eb93 100644
--- a/lib/OpenLayers/Map.js
+++ b/lib/OpenLayers/Map.js
@@ -207,7 +207,7 @@ OpenLayers.Map.prototype = {
     updateSize: function() {
         this.size = new OpenLayers.Size(
                     this.div.clientWidth, this.div.clientHeight);
-        
+        this.events.div.offsets = null;
         // Workaround for the fact that hidden elements return 0 for size.
         if (this.size.w == 0 && this.size.h == 0) {
             this.size.w = parseInt(this.div.style.width);