Animation

<!--
  示例：视图动画
  要点：view.animate 串联多段动画，easing 控制节奏，moveend 回显状态
  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>视图动画</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;font-size:12px;padding:4px 10px;border:1px solid #ccd1d9;
       border-radius:4px;background:#fff;color:#16181d;cursor:pointer}
  .bar button:hover{background:#eef0f3}
  #map{flex:1 1 auto;min-height:0;background:#eef0f3}
</style>
</head>
<body>
<div class="bar">
  <button data-city="beijing">飞往北京</button>
  <button data-city="shanghai">飞往上海</button>
  <button data-city="guangzhou">飞往广州</button>
  <button id="spin">旋转一圈</button>
  <span id="state">中心与级别在动画结束后更新</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 places = {
    beijing: [116.391263, 39.907359],
    shanghai: [121.473701, 31.230416],
    guangzhou: [113.264385, 23.129112]
  };

  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(places.beijing),
      zoom: 11
    }),
    controls: ol.control.defaults.defaults({
      attribution: false,
      rotate: false
    })
  });

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

  function flyTo(key) {
    /* 两段动画：先抬升高度，再落点到目标城市 */
    view.animate(
      { center: fromLonLat(places[key]), duration: 600 },
      { zoom: 6, duration: 700 },
      { zoom: 12, duration: 900, easing: ol.easing.inAndOut }
    );
  }

  Array.prototype.forEach.call(
    document.querySelectorAll('.bar button[data-city]'),
    function (btn) {
      btn.addEventListener('click', function () {
        flyTo(btn.getAttribute('data-city'));
      });
    }
  );

  document.getElementById('spin').addEventListener('click', function () {
    view.animate({
      rotation: view.getRotation() + 2 * Math.PI,
      duration: 2200,
      easing: ol.easing.inAndOut
    });
    /* 转完把角度归零，避免多次点击后累积 */
    view.once('moveend', function () {
      view.setRotation(0);
    });
  });

  function refresh() {
    var c = ol.proj.toLonLat(view.getCenter());
    stateEl.textContent =
      '中心 ' + c[0].toFixed(4) + ', ' + c[1].toFixed(4) +
      ' · 级别 ' + view.getZoom().toFixed(2);
  }

  view.on('moveend', refresh);
  refresh();
})();
</script>
</body>
</html>