Rectangle

<!--
  示例：矩形框选
  要点：DragBox 交互得到框选范围，再用 containsCoordinate 过滤要素
  依赖：OpenLayers 10.3.1 · jsDelivr CDN（底图 OSM，无 Key）
-->
<!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>矩形框选</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;color:#16181d}
  .bar{flex:0 0 auto;padding:8px 12px;background:#f6f7f9;border-bottom:1px solid #e3e6ea;
       display:flex;gap:14px;align-items:center;font-size:12px;color:#58606e;flex-wrap:wrap}
  .bar b{color:#16181d;font-weight:600}
  #map{flex:1 1 auto;min-height:0;background:#eef0f3}
</style>
</head>
<body>
<div class="bar">
  <span>按住 Shift 拖出矩形</span>
  <span>命中 <b id="cnt">0</b> 个要素</span>
  <span>范围 <b id="ext">—</b></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 (!window.ol) {
    document.getElementById('map').textContent = 'OpenLayers 加载失败，请检查 cdn.jsdelivr.net 是否可访问';
    return;
  }

  var feats = [];
  for (var i = 0; i < 90; i++) {
    var lon = 116.28 + (i % 15) * 0.016;
    var lat = 39.84 + Math.floor(i / 15) * 0.013;
    feats.push(new ol.Feature({
      geometry: new ol.geom.Point(ol.proj.fromLonLat([lon, lat])),
      id: 'P' + (i + 1)
    }));
  }

  var source = new ol.source.Vector({ features: feats });

  var layer = new ol.layer.Vector({
    source: source,
    style: new ol.style.Style({
      image: new ol.style.Circle({
        radius: 5,
        fill: new ol.style.Fill({ color: '#1f5fd0' }),
        stroke: new ol.style.Stroke({ color: '#fff', width: 1.5 })
      })
    })
  });

  var selStyle = new ol.style.Style({
    image: new ol.style.Circle({
      radius: 7,
      fill: new ol.style.Fill({ color: '#d64545' }),
      stroke: new ol.style.Stroke({ color: '#fff', width: 2 })
    })
  });

  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: ol.proj.fromLonLat([116.395, 39.885]), zoom: 14 }),
    controls: ol.control.defaults.defaults({ attribution: false, rotate: false })
  });

  var dragBox = new ol.interaction.DragBox({
    condition: ol.events.condition.platformModifierKeyOnly
  });

  dragBox.on('boxend', function () {
    var extent = dragBox.getGeometry().getExtent();
    var hits = 0;
    source.getFeatures().forEach(function (f) {
      var inside = extent[0] <= f.getGeometry().getCoordinates()[0] &&
                   f.getGeometry().getCoordinates()[0] <= extent[2] &&
                   extent[1] <= f.getGeometry().getCoordinates()[1] &&
                   f.getGeometry().getCoordinates()[1] <= extent[3];
      f.setStyle(inside ? selStyle : null);
      if (inside) hits++;
    });
    var ll0 = ol.proj.toLonLat([extent[0], extent[1]]);
    var ll1 = ol.proj.toLonLat([extent[2], extent[3]]);
    document.getElementById('cnt').textContent = hits;
    document.getElementById('ext').textContent =
      ll0[0].toFixed(4) + ',' + ll0[1].toFixed(4) + ' → ' +
      ll1[0].toFixed(4) + ',' + ll1[1].toFixed(4);
    source.changed();
  });

  dragBox.on('boxstart', function () {
    source.getFeatures().forEach(function (f) { f.setStyle(null); });
  });

  map.addInteraction(dragBox);
})();
</script>
</body>
</html>