Overview Map

<!--
  示例：鹰眼图
  要点：ol.control.OverviewMap 提供全局视野，主图范围框随视图联动
  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>鹰眼图</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:12px;align-items:center;font-size:12px;color:#58606e;flex-wrap:wrap}
  .bar button{font:inherit;font-size:12px;padding:4px 9px;border:1px solid #ccd1d9;
       border-radius:4px;background:#fff;color:#16181d;cursor:pointer}
  #map{flex:1 1 auto;min-height:0;background:#eef0f3}
  .ol-overviewmap{background:#f6f7f9;border:1px solid #e3e6ea;border-radius:4px}
</style>
</head>
<body>
<div class="bar">
  <button id="toggle">收起鹰眼</button>
  <span>鹰眼里的红框代表主图当前范围，拖动红框可快速定位</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') {
    document.getElementById('map').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;

  var district = new ol.Feature({
    geometry: new ol.geom.Polygon([[
      fromLonLat([116.28, 39.98]),
      fromLonLat([116.52, 39.98]),
      fromLonLat([116.52, 39.84]),
      fromLonLat([116.28, 39.84]),
      fromLonLat([116.28, 39.98])
    ]]),
    name: '中心城区'
  });

  district.setStyle(new ol.style.Style({
    fill: new ol.style.Fill({ color: 'rgba(31,95,208,0.12)' }),
    stroke: new ol.style.Stroke({ color: '#1f5fd0', width: 2 })
  }));

  var mainLayer = new ol.layer.Vector({
    source: new ol.source.Vector({ features: [district] })
  });

  /* 鹰眼用的是独立的小地图，图层需要单独给一份 */
  var overview = new ol.control.OverviewMap({
    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'}) })
    ],
    collapsed: false,
    collapsible: false,
    tipLabel: '鹰眼'
  });

  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'}) }),
      mainLayer
    ],
    view: new ol.View({
      center: fromLonLat([116.400, 39.910]),
      zoom: 12
    }),
    controls: ol.control.defaults.defaults({
      overviewMap: false,
      attribution: false
    }).extend([overview])
  });

  var btn = document.getElementById('toggle');

  btn.addEventListener('click', function () {
    var collapsed = overview.getCollapsed();
    overview.setCollapsed(!collapsed);
    btn.textContent = collapsed ? '收起鹰眼' : '展开鹰眼';
  });
})();
</script>
</body>
</html>