openlayer 获取当前视图窗口内的要素

//监听分辨率变化
Map.map.getView().on('change:resolution', function(){
   var zoom = Map.map.getView().getZoom();
   if(zoom>=10){
      console.info("当前层级:"+zoom);
      var extent =Map.map.getView().calculateExtent(Map.map.getSize());
      console.info(extent);
      var features = parent.GlobalOLTOWER.tower_750.getSource().getFeaturesInExtent(extent); //先缩小feature的范围
      console.info(features);
   }else{
      console.info("层级未达到")
   }
});

//监听地图实时的 extent
Map.map.on('moveend', function () {
   var zoom = Map.map.getView().getZoom();
   if(zoom>=10){
      console.info("当前层级:"+zoom);
      var extent =Map.map.getView().calculateExtent(Map.map.getSize());
      console.info(extent);
      var features = parent.GlobalOLTOWER.tower_750.getSource().getFeaturesInExtent(extent); //先缩小feature的范围
      console.info(features);
   }else{
      console.info("层级未达到")
   }
});