http://vttrack.fr/js/VTTrack/Aggregate.js

1OpenLayers.Layer.Aggregate=OpenLayers.Class(OpenLayers.Layer,{layers:null,initialize:function(b,c,a){OpenLayers.Layer.prototype.initialize.apply(this,[b,a]);this.layers=[];this.addLayers(c)},destroy:function(){if(this.map){this.map.events.unregister("removelayer",this,this.remove)}if(this.layers){for(var b=0,a=this.layers.length;b<a;b++){this.layers[b].aggregate=null;this.layers[b].destroy()}this.layers=null}OpenLayers.Layer.prototype.destroy.apply(this,arguments)},remove:function(b){if(b.layer!=this){return}if(this.layers){var d;for(var c=0,a=this.layers.length;c<a;c++){d=this.layers[c];if(d.map!=null){d.map.removeLayer(this.layers[c],false)}}}},clone:function(){var a=OpenLayers.Layer.prototype.clone.apply(this,arguments);a.addLayers(this.layers)},setMap:function(e){if(this.map!=null){return}if(!this.layers){return}var c;for(var b=0,a=this.layers.length;b<a;b++){c=this.layers[b];if(c.map==null){e.addLayer(c)}}var d=this.maxExtent==null;OpenLayers.Layer.prototype.setMap.apply(this,arguments);if(d){this.maxExtent=null;for(var b=0,a=this.layers.length;b<a;b++){c=this.layers[b];if(b==0){this.maxExtent=c.maxExtent.clone()}else{this.maxExtent.extend(c)}}}this.setZIndex(this.getZIndex());this.map.events.register("removelayer",this,this.remove)},removeMap:function(d){if(this.map==null){return}if(this.layers){var c;for(var b=0,a=this.layers.length;b<a;b++){c=this.layers[b];if(c.map!=null){c.map.removeLayer(c)}}}},setVisibility:function(b){this.visibility=b;OpenLayers.Layer.prototype.display.apply(this,arguments);if(this.layers&&this.map!=null){var d;for(var c=0,a=this.layers.length;c<a;c++){d=this.layers[c];if(d.isBaseLayer){continue}if(b){d.setVisibility(true)}else{d.setVisibility(false)}}}if(this.map!=null){this.map.events.triggerEvent("changelayer",{layer:this,property:"visibility"})}this.events.triggerEvent("visibilitychanged")},display:function(d){var e=this.calculateInRange();if(d!=(this.div.style.display!="none")){this.div.style.display=(d&&e)?"block":"none";if(this.layers){var c;for(var b=0,a=this.layers.length;b<a;b++){c=this.layers[b];c.display(d)}}}},initResolutions:function(){if(this.layers){var e;var c=typeof(this.options.minZoomLevel)=="number";var b=typeof(this.options.maxZoomLevel)=="number";for(var d=0,a=this.layers.length;d<a;d++){e=this.layers[d];if(d==0){if(!c&&typeof(e.minZoomLevel)=="number"){this.options.minZoomLevel=e.minZoomLevel}if(!b&&typeof(e.maxZoomLevel)=="number"){this.options.maxZoomLevel=e.maxZoomLevel}}else{if(!c&&typeof(e.minZoomLevel)=="number"){this.options.minZoomLevel=Math.min(this.options.minZoomLevel,e.minZoomLevel)}if(!b&&typeof(e.maxZoomLevel)=="number"){this.options.maxZoomLevel=Math.max(this.options.maxZoomLevel,e.maxZoomLevel)}}}}OpenLayers.Layer.prototype.initResolutions.apply(this,arguments)},getDataExtent:function(){var d=null;if(this.layers){var c;for(var b=0,a=this.layers.length;b<a;b++){c=this.layers[b];if(b==0){d=c.getDataExtent()}else{d.extend(c.getDataExtent())}}}return d},setOpacity:function(b){if(b!=this.opacity){OpenLayers.Layer.prototype.setOpacity.apply(this,arguments);if(this.layers){var d;for(var c=0,a=this.layers.length;c<a;c++){d=this.layers[c];d.setOpacity(b)}}}},setZIndex:function(d){this.div.style.zIndex=d;if(this.layers){var c;for(var b=0,a=this.layers.length;b<a;b++){c=this.layers[b];if(c.div){c.setZIndex(d-b-1)}}}},addLayer:function(d){var b;for(var c=0,a=this.layers.length;c<a;c++){b=this.layers[c];if(b==d){var e=OpenLayers.i18n("layerAlreadyAdded",{layerName:d.name});OpenLayers.Console.warn(e);return}}d.displayInLayerSwitcher=false;d.visibility=this.visibility;d.aggregate=this;this.layers.push(d);if(this.map){if(d.map==null){this.map.addLayer(d)}this.initResolutions();this.setZIndex(this.getZIndex())}},addLayers:function(c){if(!c){return}if(!(c instanceof Array)){this.addLayer(c);return}for(var b=0,a=c.length;b<a;b++){this.addLayer(c[b])}},CLASS_NAME:"OpenLayers.Layer.Aggregate"});