[OpenLayers-Commits] r3605 - in sandbox/euzuro/untiled3: examples lib/OpenLayers/Layer

Thu Jul 5 18:55:02 EDT 2007

Author: euzuro
Date: 2007-07-05 18:55:01 -0400 (Thu, 05 Jul 2007)
New Revision: 3605

Added:
   sandbox/euzuro/untiled3/examples/layerLoadMonitoring.html
Modified:
   sandbox/euzuro/untiled3/lib/OpenLayers/Layer/Grid.js
Log:
use the tile events to register when a grid layer starts and stops loading

Added: sandbox/euzuro/untiled3/examples/layerLoadMonitoring.html
===================================================================

--- sandbox/euzuro/untiled3/examples/layerLoadMonitoring.html	                        (rev 0)
+++ sandbox/euzuro/untiled3/examples/layerLoadMonitoring.html	2007-07-05 22:55:01 UTC (rev 3605)
@@ -0,0 +1,45 @@
+<html xmlns="http://www.w3.org/1999/xhtml">
+  <head>
+    <style type="text/css">
+        #map {
+            width: 800px;
+            height: 475px;
+            border: 1px solid black;
+        }
+    </style>
+    <script src="../lib/Firebug/firebug.js"></script>
+    <script src="../lib/OpenLayers.js"></script>
+    <script type="text/javascript">
+        <!--
+        var lon = 5;
+        var lat = 40;
+        var zoom = 5;
+        var map, layer;
+
+        function init(){
+            map = new OpenLayers.Map( 'map' );
+            layer = new OpenLayers.Layer.WMS( "OpenLayers WMS", 
+                    "http://labs.metacarta.com/wms/vmap0",
+                    {layers: 'basic'} , 
+                    { singleTile: false, buffer:0}
+            );
+            
+            layer.events.register("loadstart", this, function() {
+                OpenLayers.Console.log("loadstart!");
+            });
+            
+            layer.events.register("loadend", this, function() {
+                OpenLayers.Console.log("loadend!");
+            });
+            
+                                  
+            map.addLayer(layer);
+            map.setCenter(new OpenLayers.LonLat(lon, lat), zoom);
+        }
+        // -->
+    </script>
+  </head>
+  <body onload="init()">
+    <div id="map"></div>
+  </body>
+</html>

Modified: sandbox/euzuro/untiled3/lib/OpenLayers/Layer/Grid.js
===================================================================
--- sandbox/euzuro/untiled3/lib/OpenLayers/Layer/Grid.js	2007-07-05 22:34:02 UTC (rev 3604)
+++ sandbox/euzuro/untiled3/lib/OpenLayers/Layer/Grid.js	2007-07-05 22:55:01 UTC (rev 3605)
@@ -44,6 +44,12 @@
     buffer: 2,
 
     /**
+     * APIProperty: numLoadingTiles
+     * {Integer} How many tiles are still loading?
+     */
+    numLoadingTiles: 0,
+
+    /**
      * Constructor: OpenLayers.Layer.Grid
      * Create a new grid layer
      *
@@ -251,12 +257,63 @@
         var tile = this.grid[0][0];
         if (!tile) {
             tile = this.addTile(tileBounds, px);
+            
+            this.addTileMonitoringHooks(tile);
             tile.draw();
             this.grid[0][0] = tile;
         } else {
             tile.moveTo(tileBounds, px);
         }           
     },
+
+    /** 
+     * Method: addTileMonitoringHooks
+     * This function takes a tile as input and adds the appropriate hooks to 
+     *     the tile so that the layer can keep track of the loading tiles.
+     * 
+     * Parameters: 
+     * tile - {<OpenLayers.Tile>}
+     */
+    addTileMonitoringHooks: function(tile) {
+        
+        var onLoadStart = function() {
+
+            if (!tile.reloading) {
+                
+                //if there are no tiles loading then trigger a 'loadstart'
+                // event on the layer
+                if (this.numLoadingTiles == 0) {
+                    this.events.triggerEvent("loadstart");
+                }
+                
+                this.numLoadingTiles++;
+            }
+        };
+        tile.events.register("loadstart",
+                             this,
+                             onLoadStart.bindAsEventListener(this));
+
+       
+        var onReload = function() {
+            //mark the tile as reloading. This is a flag that is checked for
+            // in the 'loadstart' handler.
+            tile.reloading = true;
+        };
+        tile.events.register("reload",
+                             this,
+                             onReload.bindAsEventListener(this));
+        
+        var onLoadEnd = function() {
+            this.numLoadingTiles--;
+            if (this.numLoadingTiles == 0) {
+                this.events.triggerEvent("loadend");
+            }
+        };
+        tile.events.register("loadend",
+                             this,
+                             onLoadEnd.bindAsEventListener(this));
+    },
+
  
     /**
      * Method: initGriddedTiles
@@ -327,6 +384,7 @@
                 var tile = row[colidx++];
                 if (!tile) {
                     tile = this.addTile(tileBounds, px);
+                    this.addTileMonitoringHooks(tile);
                     row.push(tile);
                 } else {
                     tile.moveTo(tileBounds, px, false);

