Vector Labels Justify Text

<!--
  示例：OpenLayers 文本对齐与背景
  要点：textAlign 与 justify 的不同组合，配合 backgroundFill 和 padding 显示文本盒
  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>文本对齐与背景</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;flex-wrap:wrap;font-size:12px;color:#58606e}
  .bar label{display:flex;gap:5px;align-items:center;cursor:pointer}
  .bar select,.bar input[type=range]{font-size:12px}
  .bar .val{font-family:ui-monospace,Consolas,monospace;color:#1f5fd0;min-width:44px}
  .bar .sep{width:1px;height:16px;background:#d8dce2}
  #map{flex:1 1 auto;min-height:0;background:#eef0f3}
</style>
</head>
<body>
<div class="bar">
  <span>9 个点 · textAlign 左 / 中 / 右 × justify 默认 / center / left</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').textContent = 'OpenLayers 加载失败，请检查能否访问 cdn.jsdelivr.net';
    return;
  }


  var configs = [];
  var y = 39.925;
  ['left', 'center', 'right'].forEach(function (align) {
    [undefined, 'center', 'left'].forEach(function (justify) {
      configs.push({align: align, justify: justify, lat: y});
    });
    y -= 0.012;
  });

  var features = configs.map(function (config, index) {
    var lon = 116.360 + (index % 3) * 0.030;
    var lat = config.lat;
    var feature = new ol.Feature({
      geometry: new ol.geom.Point(ol.proj.fromLonLat([lon, lat]))
    });
    feature.setStyle(new ol.style.Style({
      image: new ol.style.Circle({
        radius: 8,
        fill: new ol.style.Fill({color: 'rgba(220, 40, 40, 0.12)'}),
        stroke: new ol.style.Stroke({color: '#c62828', width: 1})
      }),
      text: new ol.style.Text({
        font: '600 13px sans-serif',
        textAlign: config.align,
        justify: config.justify,
        text: '对齐演示\ntextAlign: ' + config.align +
          (config.justify ? '\njustify: ' + config.justify : ''),
        fill: new ol.style.Fill({color: '#ffffff'}),
        backgroundFill: new ol.style.Fill({color: 'rgba(140, 40, 140, 0.72)'}),
        padding: [3, 5, 3, 5]
      })
    }));
    return feature;
  });

  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'}), opacity: 0.65}),
      new ol.layer.Vector({source: new ol.source.Vector({features: features})})
    ],
    view: new ol.View({
      center: ol.proj.fromLonLat([116.390, 39.913]),
      zoom: 13
    })
  });

})();
</script>
</body>
</html>