Declutter Group

<!--
  说明：符号与标签避让的中文示例，数据在页面内生成，可独立运行。
  核心逻辑：layer declutter + style declutterMode 控制符号与文字避让
  依赖：OpenLayers 10.3.1 · jsDelivr CDN
-->
<!DOCTYPE html>
<html lang="zh-CN">
<head>
<meta name="robots" content="noindex,follow">
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>符号与标签避让</title>
<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/ol@10.3.1/ol.css">
<style>
  html,body{height:100%;margin:0}
  body{display:flex;flex-direction:column;overflow:hidden;
       font:13px/1.6 -apple-system,"Segoe UI","PingFang SC",sans-serif}
  .bar{flex:0 0 auto;padding:8px 12px;background:#f6f7f9;border-bottom:1px solid #e3e6ea;
       display:flex;gap:10px;align-items:center;flex-wrap:wrap;font-size:12px;color:#58606e}
  .bar label{display:flex;gap:5px;align-items:center;cursor:pointer}
  .bar button{font:inherit;padding:3px 9px;border:1px solid #c9ced6;background:#fff;
       border-radius:5px;cursor:pointer;color:#333}
  .bar button:hover{background:#eef2f8}
  .bar input[type=range]{width:110px;vertical-align:middle}
  .bar input[type=text]{font:inherit;padding:2px 6px;border:1px solid #c9ced6;border-radius:4px}
  #map{flex:1 1 auto;min-height:0;background:#eef0f3;position:relative}
  .panel{flex:0 0 auto;max-height:34%;overflow:auto;padding:8px 12px;font-size:12px;
       background:#fff;border-top:1px solid #e3e6ea;color:#3d4451}
  .panel pre{margin:0;font-family:Consolas,"Courier New",monospace;font-size:11px;
       white-space:pre-wrap;word-break:break-all;line-height:1.5}
  .ol-attribution{font-size:11px}

</style>
</head>
<body>
<div class="bar">
<label><input type="checkbox" id="decl" checked> 启用避让</label>
<span id="info">—</span>
</div>
<div id="map"></div>

<script src="https://cdn.jsdelivr.net/npm/ol@10.3.1/dist/ol.js"></script>
<script>
(function () {
  'use strict';

  if (typeof ol === 'undefined') {
    var errBox = document.getElementById('map');
    if (errBox) {
      errBox.innerHTML = '<div style="padding:20px;color:#b42318">OpenLayers 加载失败，请检查能否访问 cdn.jsdelivr.net</div>';
    }
    return;
  }

  var fromLonLat = ol.proj.fromLonLat;
  function rand(seed) {
    var v = Math.sin(seed * 12.9898) * 43758.5453;
    return v - Math.floor(v);
  }

  var features = [];
  for (var i = 0; i < 26; i++) {
    features.push(new ol.Feature({
      geometry: new ol.geom.Point(fromLonLat([
        116.32 + rand(i + 5) * 0.16,
        39.86 + rand(i + 41) * 0.12
      ])),
      name: '站点 ' + (i + 1),
      tone: i % 3
    }));
  }

  var colors = ['#1f5fd0', '#26966e', '#ee602a'];

  function buildLayer(declutter) {
    return new ol.layer.Vector({
      source: new ol.source.Vector({features: features}),
      declutter: declutter,
      style: function (f) {
        return new ol.style.Style({
          image: new ol.style.Circle({
            radius: 9,
            fill: new ol.style.Fill({color: colors[f.get('tone')]}),
            stroke: new ol.style.Stroke({color: '#ffffff', width: 2}),
            declutterMode: 'declutter'
          }),
          text: new ol.style.Text({
            text: f.get('name'),
            offsetY: 18,
            font: '600 11px sans-serif',
            fill: new ol.style.Fill({color: '#ffffff'}),
            stroke: new ol.style.Stroke({color: 'rgba(30,40,55,0.85)', width: 3}),
            declutterMode: 'declutter'
          })
        });
      }
    });
  }

  var layer = buildLayer(true);

  var map = new ol.Map({
    target: 'map',
    layers: [new ol.layer.Tile({source: new ol.source.XYZ({url: 'https://server.arcgisonline.com/ArcGIS/rest/services/World_Street_Map/MapServer/tile/{z}/{y}/{x}', attributions: 'Tiles © Esri'})}), layer],
    view: new ol.View({center: fromLonLat([116.40, 39.92]), zoom: 13}),
    controls: ol.control.defaults.defaults({attribution: false, zoom: true, rotate: false})
  });

  var info = document.getElementById('info');

  function report(declutter) {
    info.textContent = declutter
      ? '避让开启 · 26 个点位，重叠标签自动隐藏'
      : '避让关闭 · 26 个点位，标签全部绘制、允许压盖';
  }

  document.getElementById('decl').addEventListener('change', function () {
    map.removeLayer(layer);
    layer = buildLayer(this.checked);
    map.addLayer(layer);
    report(this.checked);
  });

  report(true);
})();
</script>
</body>
</html>