Add a javascript file to provide OSM layers for OpenStreetMap.

public/openlayers/OpenStreetMap.js

@@ -0,0 +1,144 @@
+/**
+ * Namespace: Util.OSM
+ */
+OpenLayers.Util.OSM = {};
+
+/**
+ * Constant: MISSING_TILE_URL
+ * {String} URL of image to display for missing tiles
+ */
+OpenLayers.Util.OSM.MISSING_TILE_URL = "http://openstreetmap.org/openlayers/img/404.png";
+
+/**
+ * Property: originalOnImageLoadError
+ * {Function} Original onImageLoadError function.
+ */
+OpenLayers.Util.OSM.originalOnImageLoadError = OpenLayers.Util.onImageLoadError;
+
+/**
+ * Function: onImageLoadError 
+ */
+OpenLayers.Util.onImageLoadError = function() {
+    if (this.src.match(/^http:\/\/[abc]\.[a-z]+\.openstreetmap\.org/)) {
+        this.src = OpenLayers.Util.OSM.MISSING_TILE_URL;
+    } else {
+        OpenLayers.Util.OSM.originalOnImageLoadError;
+    }
+};
+
+/**
+ * @requires OpenLayers/Layer/TMS.js
+ * 
+ * Class: OpenLayers.Layer.OSM
+ * 
+ * Inherits from:
+ *  - <OpenLayers.Layer.TMS>
+ */
+OpenLayers.Layer.OSM = OpenLayers.Class(OpenLayers.Layer.TMS, {
+    /**
+     * Constructor: OpenLayers.Layer.OSM
+     * 
+     * Parameters:
+     * name - {String}
+     * url - {String}
+     * options - {Object} Hashtable of extra options to tag onto the layer
+     */
+    initialize: function(name, url, options) {
+        options = OpenLayers.Util.extend(options, { attribution: "Powered by <a href='http://openstreetmap.org/'>OpenStreetMap</a>" });
+        OpenLayers.Layer.TMS.prototype.initialize.apply(this, arguments);
+    },    
+    
+    /**
+     * Method: getUrl
+     * 
+     * Parameters:
+     * bounds - {<OpenLayers.Bounds>}
+     * 
+     * Returns:
+     * {String} A string with the layer's url and parameters and also the 
+     *          passed-in bounds and appropriate tile size specified as 
+     *          parameters
+     */
+    getURL: function (bounds) {
+        var res = this.map.getResolution();
+        var x = Math.round((bounds.left - this.maxExtent.left) / (res * this.tileSize.w));
+        var y = Math.round((this.maxExtent.top - bounds.top) / (res * this.tileSize.h));
+        var z = this.map.getZoom();
+        var limit = Math.pow(2, z);
+
+        if (y < 0 || y >= limit)
+        {
+            return OpenLayers.Util.OSM.MISSING_TILE_URL;
+        }
+        else
+        {
+            x = ((x % limit) + limit) % limit;
+
+            var url = this.url;
+            var path = z + "/" + x + "/" + y + ".png";
+
+            if (url instanceof Array)
+            {
+                url = this.selectUrl(path, url);
+            }
+
+            return url + path;
+        }
+    },
+
+    CLASS_NAME: "OpenLayers.Layer.OSM"
+});
+
+/**
+ * Class: OpenLayers.Layer.OSM.Mapnik
+ * 
+ * Inherits from:
+ *  - <OpenLayers.Layer.OSM>
+ */
+OpenLayers.Layer.OSM.Mapnik = OpenLayers.Class(OpenLayers.Layer.OSM, {
+    /**
+     * Constructor: OpenLayers.Layer.OSM.Mapnik
+     * 
+     * Parameters:
+     * name - {String}
+     * options - {Object} Hashtable of extra options to tag onto the layer
+     */
+    initialize: function(name, options) {
+        var url = [
+            "http://a.tile.openstreetmap.org/",
+            "http://b.tile.openstreetmap.org/",
+            "http://c.tile.openstreetmap.org/"
+        ];
+        var newArguments = [name, url, options];
+        OpenLayers.Layer.OSM.prototype.initialize.apply(this, newArguments);
+    },    
+
+    CLASS_NAME: "OpenLayers.Layer.OSM.Mapnik"
+});
+
+/**
+ * Class: OpenLayers.Layer.OSM.Osmarender
+ * 
+ * Inherits from:
+ *  - <OpenLayers.Layer.OSM>
+ */
+OpenLayers.Layer.OSM.Osmarender = OpenLayers.Class(OpenLayers.Layer.OSM, {
+    /**
+     * Constructor: OpenLayers.Layer.OSM.Osmarender
+     * 
+     * Parameters:
+     * name - {String}
+     * options - {Object} Hashtable of extra options to tag onto the layer
+     */
+    initialize: function(name, options) {
+        var url = [
+            "http://a.tah.openstreetmap.org/Tiles/tile.php/",
+            "http://b.tah.openstreetmap.org/Tiles/tile.php/",
+            "http://c.tah.openstreetmap.org/Tiles/tile.php/"
+        ];
+        var newArguments = [name, url, options];
+        OpenLayers.Layer.OSM.prototype.initialize.apply(this, newArguments);
+    },    
+
+    CLASS_NAME: "OpenLayers.Layer.OSM.Osmarender"
+});