Performance

<!--
  示例：deck.gl 性能对比
  要点：同一份 26 万点数据在精简配置与高开销配置下渲染，实时显示帧率差异
  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>性能对比</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:10px;align-items:center;font-size:12px;color:#8b93a1;flex-wrap:wrap}
  .bar b{color:#58a6ff;font-weight:600}
  .bar button{font:inherit;font-size:12px;padding:3px 10px;border-radius:5px;cursor:pointer;
              border:1px solid #303845;background:#1d2531;color:#c8d2e0}
  .bar button:hover{background:#253040}
  .bar button.on{background:#2c4a7a;border-color:#4f8ad6;color:#dfe9ff}
  .bar .sep{width:1px;height:18px;background:#2a313c;margin:0 4px}
  .fps{margin-left:auto;font-size:12px;color:#8b93a1}
  .fps b{font-size:19px;color:#61d99b;font-variant-numeric:tabular-nums}
  .fps b.low{color:#ff8c74}
  #cv{flex:1 1 auto;min-height:0;width:100%}
</style>
</head>
<body>
<div class="bar">
  <span>点数 <b id="n">—</b></span>
  <span class="sep"></span>
  <button data-mode="fast" class="on">精简配置</button>
  <button data-mode="heavy">高开销配置</button>
  <span class="sep"></span>
  <span id="desc">像素半径 · 无描边 · 无拾取</span>
  <span class="fps">帧率 <b id="fps">—</b> fps · 帧耗时 <b id="ft" style="font-size:12px">—</b> 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 centers = [
    [116.39, 39.90], [121.47, 31.23], [113.26, 23.12],
    [104.06, 30.57], [114.05, 22.54], [108.94, 34.34]
  ];

  var data = [];
  for (var i = 0; i < 260000; i++) {
    var c = centers[i % centers.length];
    var r = Math.sqrt(Math.random()) * 1.0;
    var a = Math.random() * Math.PI * 2;
    data.push({
      lng: c[0] + Math.cos(a) * r,
      lat: c[1] + Math.sin(a) * r * 0.8,
      v: Math.random()
    });
  }

  document.getElementById('n').textContent = data.length.toLocaleString();

  function baseProps(id) {
    return {
      id: id,
      data: data,
      getPosition: function (d) { return [d.lng, d.lat]; },
      getFillColor: function (d) {
        return [70 + d.v * 150, 150 - d.v * 40, 240 - d.v * 120, 175];
      }
    };
  }

  var fastLayer = new deck.ScatterplotLayer(Object.assign(baseProps('fast'), {
    getRadius: 1.6,
    radiusUnits: 'pixels',
    radiusMinPixels: 1,
    radiusMaxPixels: 3,
    pickable: false
  }));

  function heavyLayers() {
    var a = new deck.ScatterplotLayer(Object.assign(baseProps('heavy-a'), {
      getRadius: 2.6,
      radiusUnits: 'pixels',
      radiusMinPixels: 1,
      radiusMaxPixels: 6,
      stroked: true,
      getLineColor: [10, 16, 26, 120],
      lineWidthUnits: 'pixels',
      getLineWidth: 1,
      antialiasing: true,
      pickable: true
    }));
    var b = new deck.ScatterplotLayer(Object.assign(baseProps('heavy-b'), {
      getRadius: 9,
      radiusUnits: 'pixels',
      radiusMaxPixels: 14,
      getFillColor: [90, 170, 255, 16],
      pickable: false
    }));
    var c = new deck.ScatterplotLayer(Object.assign(baseProps('heavy-c'), {
      getRadius: 17,
      radiusUnits: 'pixels',
      radiusMaxPixels: 26,
      getFillColor: [90, 170, 255, 7],
      pickable: false
    }));
    return [a, b, c];
  }

  var layers = [fastLayer];

  var deckgl = new deck.Deck({
    canvas: 'cv',
    width: '100%',
    height: '100%',
    initialViewState: {
      longitude: 110.0,
      latitude: 31.8,
      zoom: 4.0,
      pitch: 28,
      bearing: 0,
      maxPitch: 65
    },
    controller: true,
    layers: layers,
    useDevicePixels: true
  });

  var desc = document.getElementById('desc');
  var buttons = document.querySelectorAll('[data-mode]');

  for (var b = 0; b < buttons.length; b++) {
    buttons[b].addEventListener('click', function (e) {
      var mode = e.currentTarget.getAttribute('data-mode');
      for (var k = 0; k < buttons.length; k++) {
        buttons[k].classList.toggle('on', buttons[k] === e.currentTarget);
      }

      if (mode === 'fast') {
        deckgl.setProps({ layers: [fastLayer], useDevicePixels: true, getTooltip: null });
        desc.textContent = '像素半径 · 无描边 · 无拾取';
      } else {
        deckgl.setProps({
          layers: heavyLayers(),
          useDevicePixels: true,
          getTooltip: function (info) {
            if (!info.object) return null;
            return info.object.lng.toFixed(3) + ', ' + info.object.lat.toFixed(3);
          }
        });
        desc.textContent = '像素半径 · 描边 · 抗锯齿 · 拾取 · 三层叠加';
      }
    });
  }

  /* 帧率统计：只统计 requestAnimationFrame 的实际回调频率 */
  var frames = 0;
  var last = performance.now();
  var fpsEl = document.getElementById('fps');
  var ftEl = document.getElementById('ft');

  function tick(now) {
    frames++;
    var span = now - last;
    if (span >= 600) {
      var fps = Math.round(frames * 1000 / span);
      fpsEl.textContent = fps;
      fpsEl.classList.toggle('low', fps < 30);
      ftEl.textContent = fps > 0 ? (1000 / fps).toFixed(1) : '—';
      frames = 0;
      last = now;
    }
    requestAnimationFrame(tick);
  }
  requestAnimationFrame(tick);

  window.__deck = deckgl;
})();
</script>
</body>
</html>