Custom Controls

<!--
  说明：自定义地图控件的中文示例，数据在页面内生成，可独立运行。
  核心逻辑：class extends ol.control.Control + element + view 事件更新
  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>自定义地图控件</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}
  .coord-badge{position:absolute;top:8px;right:8px;z-index:2;background:rgba(255,255,255,.94);
    border:1px solid #d5dae2;border-radius:6px;padding:6px 10px;font-size:12px;color:#2b3444;
    box-shadow:0 1px 3px rgba(0,0,0,.14);pointer-events:none}
  .coord-badge b{color:#1f5fd0;font-weight:600}
</style>
</head>
<body>
<div class="bar">
<span>右上角面板由自定义控件提供</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') {
    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;
  var badgeEl = document.createElement('div');
  badgeEl.className = 'coord-badge';
  badgeEl.setAttribute('role', 'status');
  badgeEl.setAttribute('aria-live', 'polite');

  class CoordBadge extends ol.control.Control {
    constructor() {
      super({element: badgeEl});
    }
  }

  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([116.397, 39.909]), zoom: 11}),
    controls: ol.control.defaults.defaults({attribution: false, zoom: true, rotate: false})
  });

  map.addControl(new CoordBadge());

  var view = map.getView();
  var info = document.getElementById('info');

  function update() {
    var c = ol.proj.toLonLat(view.getCenter());
    badgeEl.innerHTML = '缩放 <b>' + view.getZoom().toFixed(1) + '</b><br>中心 <b>' +
      c[0].toFixed(3) + ', ' + c[1].toFixed(3) + '</b>';
    info.textContent = '控件已挂载 · 拖动地图观察面板数值';
  }

  view.on(['change:center', 'change:resolution'], update);
  update();
})();
</script>
</body>
</html>