Icon Scale

<!--
  说明：图标与文字缩放
  核心逻辑：Icon.scale 与 Text.scale 同步调整，Canvas 生成图钉并固定锚点
  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>图标与文字缩放</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:12px;align-items:center;font-size:12px;color:#58606e;flex-wrap:wrap}
  .bar input[type=range]{width:150px}
  #info{margin-left:auto}
  #map{flex:1 1 auto;min-height:0;background:#eef0f3}
</style>
</head>
<body>
<div class="bar">
  <label>整体缩放 <input type="range" id="scale" min="0.5" max="2.5" step="0.1" value="1"></label>
  <span id="sv">1.0×</span>
  <label><input type="checkbox" id="txt" checked> 显示文字</label>
  <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;

  function pinDataUrl() {
    var canvas = document.createElement('canvas');
    canvas.width = 32;
    canvas.height = 44;
    var ctx = canvas.getContext('2d');

    ctx.beginPath();
    ctx.moveTo(16, 43);
    ctx.bezierCurveTo(4, 26, 2, 20, 2, 14);
    ctx.arc(16, 14, 14, Math.PI, 0);
    ctx.bezierCurveTo(30, 20, 28, 26, 16, 43);
    ctx.closePath();
    ctx.fillStyle = '#1f5fd0';
    ctx.fill();
    ctx.strokeStyle = '#ffffff';
    ctx.lineWidth = 2;
    ctx.stroke();

    ctx.beginPath();
    ctx.arc(16, 14, 5, 0, Math.PI * 2);
    ctx.fillStyle = '#ffffff';
    ctx.fill();

    return canvas.toDataURL();
  }

  var pin = pinDataUrl();
  var scale = 1;
  var showText = true;

  var features = [
    [116.36, 39.94, '北区'],
    [116.44, 39.90, '中区'],
    [116.38, 39.86, '南区']
  ].map(function (p) {
    return new ol.Feature({
      geometry: new ol.geom.Point(fromLonLat([p[0], p[1]])),
      name: p[2]
    });
  });

  function styleFn(feature) {
    var styles = [new ol.style.Style({
      image: new ol.style.Icon({
        src: pin,
        scale: scale,
        anchor: [0.5, 1]
      })
    })];

    if (showText) {
      styles.push(new ol.style.Style({
        text: new ol.style.Text({
          text: feature.get('name'),
          scale: scale,
          font: '600 12px sans-serif',
          offsetY: 6,
          fill: new ol.style.Fill({ color: '#16181d' }),
          stroke: new ol.style.Stroke({ color: '#ffffff', width: 3 })
        })
      }));
    }
    return styles;
  }

  var layer = new ol.layer.Vector({
    source: new ol.source.Vector({ features: features }),
    style: styleFn
  });

  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([116.40, 39.90]), zoom: 13, minZoom: 2, maxZoom: 19 }),
    controls: ol.control.defaults.defaults({ attribution: false, rotate: false })
  });

  document.getElementById('scale').addEventListener('input', function () {
    scale = Number(this.value);
    document.getElementById('sv').textContent = scale.toFixed(1) + '×';
    layer.changed();
  });

  document.getElementById('txt').addEventListener('change', function () {
    showText = this.checked;
    layer.changed();
  });

  document.getElementById('info').textContent = '图标由 Canvas 生成';
})();
</script>
</body>
</html>