Extent Interaction

<!--
  说明：范围交互
  核心逻辑：ol.interaction.Extent 拖框，extentchanged 读范围并用 transformExtent 转经纬度
  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>范围交互</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;font-size:12px;color:#58606e;flex-wrap:wrap}
  .bar button{font:inherit;padding:4px 10px;border:1px solid #c9d0da;border-radius:5px;
              background:#fff;color:#1f2a37;cursor:pointer}
  #info{margin-left:auto;font-family:Consolas,Menlo,monospace}
  #map{flex:1 1 auto;min-height:0;background:#eef0f3}
</style>
</head>
<body>
<div class="bar">
  <button id="clear">清除范围</button>
  <span>拖拽矩形边角调整范围</span>
  <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') {
    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 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'}) })],
    view: new ol.View({ center: fromLonLat([116.391, 39.907]), zoom: 10, minZoom: 2, maxZoom: 19 }),
    controls: ol.control.defaults.defaults({ attribution: false, rotate: false })
  });

  var extent = new ol.interaction.Extent({
    extent: ol.proj.transformExtent([116.30, 39.85, 116.48, 39.96], 'EPSG:4326', 'EPSG:3857'),
    boxStyle: new ol.style.Style({
      fill: new ol.style.Fill({ color: 'rgba(31,95,208,0.10)' }),
      stroke: new ol.style.Stroke({ color: '#1f5fd0', width: 2 }),
      image: new ol.style.Circle({
        radius: 6,
        fill: new ol.style.Fill({ color: '#ffffff' }),
        stroke: new ol.style.Stroke({ color: '#1f5fd0', width: 2 })
      })
    })
  });

  map.addInteraction(extent);

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

  function report() {
    var e = extent.getExtent();
    if (!e) {
      info.textContent = '未选择范围';
      return;
    }
    var ll = ol.proj.transformExtent(e, 'EPSG:3857', 'EPSG:4326');
    info.textContent = '西 ' + ll[0].toFixed(4) + ' · 南 ' + ll[1].toFixed(4) +
      ' · 东 ' + ll[2].toFixed(4) + ' · 北 ' + ll[3].toFixed(4);
  }

  extent.on('extentchanged', report);

  document.getElementById('clear').addEventListener('click', function () {
    extent.clear();
    info.textContent = '未选择范围';
  });

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