Transitions

<!--
  示例：属性过渡
  要点：transitions 配置让半径在 800 毫秒内插值，切换两档时平滑变化
  依赖：deck.gl 9.0 · 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>属性过渡</title>
<style>
  html,body{height:100%;margin:0;background:#0d1117}
  body{display:flex;flex-direction:column;overflow:hidden;
       font:13px/1.6 -apple-system,"Segoe UI","PingFang SC",sans-serif;color:#e6e8ec}
  .bar{position:relative;z-index:5;flex:0 0 auto;padding:8px 12px;background:#161b22;border-bottom:1px solid #252c36;
       display:flex;gap:14px;align-items:center;font-size:12px;color:#8b93a1;flex-wrap:wrap}
  .bar b{color:#58a6ff;font-weight:600}
  .bar label{display:flex;align-items:center;gap:5px;cursor:pointer}
  .bar input[type=checkbox]{accent-color:#4f9ef8}
  .bar input[type=range]{width:150px;accent-color:#4f9ef8}
  .bar button{font:inherit;font-size:12px;padding:3px 10px;border-radius:4px;cursor:pointer;
       border:1px solid #2f3947;background:#1d242e;color:#c9d3e0}
  .bar button:hover{background:#26303d}
  #cv{flex:1 1 auto;min-height:0;width:100%;display:block}

</style>
</head>
<body>
<div class="bar"><button id="swap">切换半径</button><span>两档 2 px 与 7 px · 过渡 800 ms</span></div>
<canvas id="cv"></canvas>
<script src="https://cdn.jsdelivr.net/npm/deck.gl@9.0.35/dist.min.js"></script>
<script>
(function () {
  'use strict';

  if (typeof deck === 'undefined') {
    document.body.innerHTML =
      '<div style="padding:24px;color:#ff8c74">deck.gl 加载失败，请检查能否访问 cdn.jsdelivr.net</div>';
    return;
  }
  var pts = [];
  for (var i = 0; i < 4000; i++) {
    pts.push({
      lng: 116.24 + Math.random() * 0.32,
      lat: 39.80 + Math.random() * 0.18,
      v: Math.random()
    });
  }

  var big = false;

  function makeLayer() {
    return new deck.ScatterplotLayer({
      id: 'points',
      data: pts,
      getPosition: function (d) { return [d.lng, d.lat]; },
      getRadius: big ? 7 : 2,
      radiusUnits: 'pixels',
      getFillColor: function (d) {
        return [Math.round(90 + 150 * d.v), Math.round(180 - 70 * d.v), 250 - 100 * d.v, 190];
      },
      transitions: {
        getRadius: {
          duration: 800,
          easing: function (t) { return t * (2 - t); }
        }
      }
    });
  }

  var deckgl = new deck.Deck({
    canvas: 'cv',
    width: '100%',
    height: '100%',
    initialViewState: { longitude: 116.40, latitude: 39.89, zoom: 10.4, pitch: 0, bearing: 0 },
    controller: true,
    layers: [makeLayer()]
  });

  document.getElementById('swap').addEventListener('click', function () {
    big = !big;
    deckgl.setProps({ layers: [makeLayer()] });
  });
  window.__deck = deckgl;
})();
</script>
</body>
</html>