mapboxgl区划标签避让不遮盖实现的代码详解

new mapboxgl.Marker(el)
    .setLngLat([dataTemp.lon,dataTemp.lat])
    .addTo(map);

  map.addSource(sourceId, {
   "type": "geojson",
   "data": {
     "type": "FeatureCollection",
     "features": _this.formatData(datas,map) 
   },
   "cluster": true,
   "clusterRadius": 35 // 聚合半径
  });

 map.addLayer({//添加区划标签图层
   'id': layerId,
   'type': 'symbol',
   'source': sourceId,
   'layout': {
    'visibility': 'visible',
    'text-field': ['get', 'regionname'],
    'text-font': ['Helvetica Neue', 'Arial', 'Helvetica', 'sans-serif'],
    'text-offset': [0, 0],
    'text-anchor': 'top',
    'text-size':14,
   },
   'paint':{
    'text-color':'#000000',
    
   }
  });

map.on('mouseenter', layerId, function(e) {
   let markerData = e.features[0].properties;
   _this.clearMarker(map);//先清除上次的弹窗
   _this.addMarker(markerData,map);//打开本次区划弹窗
  });
addMarker(){
  let className = 'region-selected-marker-box region-selected-marker-box-';
  let html = "自定义现实内容"；
  var popup = new mapboxgl.Popup({
   offset: [20,5], 
   className: className,
   anchor:'left',
   closeButton:false
  })
   .setLngLat([lon,lat])
   .setHTML(html)
   .setMaxWidth("300px")
   .addTo(map);
 }