function mail_crypt(mail_source) {
    var mail_dest = '';

    for(t = 0; t < mail_source.length; t++) {
        char_value = mail_source.charCodeAt(t);
        char_value -= 3;
        mail_dest += String.fromCharCode(char_value);
    }
    window.location.href = "mailto:" + mail_dest;
}


function map_init() {
    // Position und Zoomstufe der Karte
    var lon = 13.30161536699005;
    var lat = 52.52359289197206;
    var zoom = 10;

    OpenLayers.Lang.setCode('de');
    // projection: new OpenLayers.Projection("EPSG:900913"),
    map = new OpenLayers.Map("map2", {
        
        displayProjection: new OpenLayers.Projection("EPSG:4326"),
        controls: [
            new OpenLayers.Control.MouseDefaults(),
            new OpenLayers.Control.LayerSwitcher(),
            new OpenLayers.Control.PanZoomBar()
        ],
        maxExtent: new OpenLayers.Bounds(-20037508.34,-20037508.34, 20037508.34, 20037508.34),
        numZoomLevels: 18,
        maxResolution: 156543,
        units: 'meters'
    });

    layer_mapnik = new OpenLayers.Layer.OSM.Mapnik("Mapnik");
    layer_markers = new OpenLayers.Layer.Markers("Address", {
        projection: new OpenLayers.Projection("EPSG:4326"), 
    	visibility: true, displayInLayerSwitcher: false
    });

    map.addLayers([layer_mapnik, layer_markers]);

    // map.addLayer(new OpenLayers.Layer.OSM());

    var layer = new OpenLayers.Layer.Vector(
        "POIs", {
            strategies: [new OpenLayers.Strategy.BBOX({resFactor: 1.1})],
            protocol: new OpenLayers.Protocol.HTTP({
                url: "data.php",
                format: new OpenLayers.Format.Text()
            })
    });
    map.addLayer(layer);
 
    //Set start centrepoint and zoom    
    var lonLat = new OpenLayers.LonLat(lon, lat)
          .transform(
            new OpenLayers.Projection("EPSG:4326"), // transform from WGS 1984
            map.getProjectionObject() // to Spherical Mercator Projection
          );
    map.setCenter (lonLat, zoom);

    // Interaction; not needed for initial display.
    selectControl = new OpenLayers.Control.SelectFeature(layer);
    map.addControl(selectControl);
    selectControl.activate();
    layer.events.on({
        'featureselected': onFeatureSelect,
        'featureunselected': onFeatureUnselect
    });


    // Popup und Popuptext mit evtl. Grafik
    /*var popuptext="<font color=\"black\"><b>Thomas Heiles<br>Stra&szlig;e 123<br>54290 Trier</b><p><img src=\"anke.jpg\" width=\"192\" height=\"256\"></p></font>";
 
    // Position des Markers
    // addMarker(layer_markers, 6.641389, 49.756667, popuptext);
    */
}

// Needed only for interaction, not for the display.
function onPopupClose(evt) {
    // 'this' is the popup.
    selectControl.unselect(this.feature);
}

function onFeatureSelect(evt) {
    feature = evt.feature;
    popup = new OpenLayers.Popup.FramedCloud("featurePopup",
        feature.geometry.getBounds().getCenterLonLat(),
        new OpenLayers.Size(100,100),
        "<h2>"+feature.attributes.title + "</h2>" + feature.attributes.description,
        null,
        true,
        onPopupClose
    );
    feature.popup = popup;
    popup.feature = feature;
    map.addPopup(popup);
}

function onFeatureUnselect(evt) {
    feature = evt.feature;
    if (feature.popup) {
       popup.feature = null;
        map.removePopup(feature.popup);
        feature.popup.destroy();
        feature.popup = null;
    }
}

// ----------------------------------------------

function jumpTo(lon, lat, zoom) {
    var x = Lon2Merc(lon);
    var y = Lat2Merc(lat);
    map.setCenter(new OpenLayers.LonLat(x, y), zoom);
    return false;
}
 
function Lon2Merc(lon) {
    return 20037508.34 * lon / 180;
}
 
function Lat2Merc(lat) {
    var PI = 3.14159265358979323846;
    lat = Math.log(Math.tan( (90 + lat) * PI / 360)) / (PI / 180);
    return 20037508.34 * lat / 180;
}
 
function addMarker(layer, lon, lat, popupContentHTML) {
 
    var ll = new OpenLayers.LonLat(Lon2Merc(lon), Lat2Merc(lat));
    var feature = new OpenLayers.Feature(layer, ll); 
    feature.closeBox = true;
    feature.popupClass = OpenLayers.Class(OpenLayers.Popup.FramedCloud, {minSize: new OpenLayers.Size(300, 180) } );
    feature.data.popupContentHTML = popupContentHTML;
    feature.data.overflow = "hidden";
 
    var marker = new OpenLayers.Marker(ll);
    marker.feature = feature;
 
    var markerClick = function(evt) {
        if (this.popup == null) {
            this.popup = this.createPopup(this.closeBox);
            map.addPopup(this.popup);
            this.popup.show();
        } else {
            this.popup.toggle();
        }
        OpenLayers.Event.stop(evt);
    };
    marker.events.register("mousedown", feature, markerClick);
 
    layer.addMarker(marker);
    map.addPopup(feature.createPopup(feature.closeBox));
}
 
function getCycleTileURL(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 null;
   }
   else
   {
     x = ((x % limit) + limit) % limit;
 
     return this.url + z + "/" + x + "/" + y + "." + this.type;
   }
}