Dynamic Data

<!--
  说明：动态数据
  核心逻辑：定时器推进坐标并原地更新 Point 几何，矢量源自动重绘
  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>动态数据</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}
  #map{flex:1 1 auto;min-height:0;background:#eef0f3}
</style>
</head>
<body>
<div class="bar">
  <button id="toggle">暂停</button>
  <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 box = { west: 116.20, east: 116.58, south: 39.75, north: 40.02 };
  var vehicles = [];

  var source = new ol.source.Vector();

  for (var i = 0; i < 30; i++) {
    var v = {
      lon: box.west + Math.random() * (box.east - box.west),
      lat: box.south + Math.random() * (box.north - box.south),
      heading: Math.random() * Math.PI * 2,
      speed: 0.0004 + Math.random() * 0.0008
    };
    v.feature = new ol.Feature({ geometry: new ol.geom.Point(fromLonLat([v.lon, v.lat])) });
    v.feature.set('rot', v.heading);
    vehicles.push(v);
    source.addFeature(v.feature);
  }

  var layer = new ol.layer.Vector({
    source: source,
    style: function (feature) {
      return new ol.style.Style({
        image: new ol.style.RegularShape({
          points: 3,
          radius: 8,
          rotation: -feature.get('rot'),
          fill: new ol.style.Fill({ color: '#1f5fd0' }),
          stroke: new ol.style.Stroke({ color: '#ffffff', width: 1.5 })
        })
      });
    }
  });

  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([116.39, 39.88]), zoom: 12, minZoom: 2, maxZoom: 19 }),
    controls: ol.control.defaults.defaults({ attribution: false, rotate: false })
  });

  var info = document.getElementById('info');
  var running = true;
  var ticks = 0;

  setInterval(function () {
    if (!running) return;
    ticks++;
    vehicles.forEach(function (v) {
      v.lon += Math.cos(v.heading) * v.speed;
      v.lat += Math.sin(v.heading) * v.speed;

      if (v.lon < box.west || v.lon > box.east) {
        v.heading = Math.PI - v.heading;
        v.lon = Math.min(Math.max(v.lon, box.west), box.east);
      }
      if (v.lat < box.south || v.lat > box.north) {
        v.heading = -v.heading;
        v.lat = Math.min(Math.max(v.lat, box.south), box.north);
      }
      v.feature.getGeometry().setCoordinates(fromLonLat([v.lon, v.lat]));
      v.feature.set('rot', v.heading);
    });
    if (ticks % 5 === 0) {
      info.textContent = '车辆 ' + vehicles.length + ' 辆 · 已推进 ' + ticks + ' 帧';
    }
  }, 120);

  document.getElementById('toggle').addEventListener('click', function () {
    running = !running;
    this.textContent = running ? '暂停' : '继续';
    info.textContent = running ? '运行中' : '已暂停';
  });

  info.textContent = '运行中';
})();
</script>
</body>
</html>