WMS Tiled Wrap 180

<!--
  示例：OpenLayers WMS 跨 180 度
  要点：TileWMS 的 wrapX 默认开启，世界副本在 180 度经线两侧连续显示
  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>WMS 跨 180 度</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>wrapX: true</span>
  <span class="sep"></span>
  <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').textContent = 'OpenLayers 加载失败，请检查能否访问 cdn.jsdelivr.net';
    return;
  }

  /* ---- 页面内合成的世界轮廓，用于跨 180 度与瓦片顺序演示 ---- */
  var WORLD_BLOCKS = [
    {name: '亚洲', color: '#b6d7a8', pts: [[60, 5], [145, 5], [145, 60], [60, 60]]},
    {name: '欧洲', color: '#9fc5e8', pts: [[-10, 35], [60, 35], [60, 70], [-10, 70]]},
    {name: '非洲', color: '#ffe599', pts: [[-20, -35], [50, -35], [50, 35], [-20, 35]]},
    {name: '美洲', color: '#f4b183', pts: [[-170, -20], [-50, -20], [-50, 60], [-170, 60]]}
  ];

  function worldParam(src, name) {
    var m = new RegExp('[?&]' + name + '=([^&]*)').exec(src || '');
    return m ? decodeURIComponent(m[1].replace(/\+/g, ' ')) : '';
  }

  function worldDraw(ctx, w, h, bbox) {
    var x0 = bbox[0], y0 = bbox[1], x1 = bbox[2], y1 = bbox[3];
    ctx.fillStyle = '#dbe9f4';
    ctx.fillRect(0, 0, w, h);
    function px(p) {
      var c = ol.proj.fromLonLat(p);
      return [(c[0] - x0) / (x1 - x0) * w, (y1 - c[1]) / (y1 - y0) * h];
    }
    WORLD_BLOCKS.forEach(function (block) {
      var pts = block.pts.map(px);
      ctx.beginPath();
      ctx.moveTo(pts[0][0], pts[0][1]);
      for (var i = 1; i < pts.length; ++i) {
        ctx.lineTo(pts[i][0], pts[i][1]);
      }
      ctx.closePath();
      ctx.globalAlpha = 0.8;
      ctx.fillStyle = block.color;
      ctx.fill();
      ctx.globalAlpha = 1;
      ctx.strokeStyle = '#6c7d8c';
      ctx.stroke();
      if (w >= 200) {
        ctx.fillStyle = '#2f3d4a';
        ctx.font = '500 12px sans-serif';
        ctx.textAlign = 'center';
        ctx.fillText(block.name, (pts[0][0] + pts[2][0]) / 2, (pts[0][1] + pts[2][1]) / 2);
      }
    });
    ctx.strokeStyle = 'rgba(80, 95, 110, 0.25)';
    ctx.strokeRect(0.5, 0.5, w - 1, h - 1);
  }

  function worldToURL(w, h, bbox) {
    var canvas = document.createElement('canvas');
    canvas.width = w;
    canvas.height = h;
    worldDraw(canvas.getContext('2d'), w, h, bbox);
    return canvas.toDataURL('image/png');
  }


  var wmsSource = new ol.source.TileWMS({
    url: 'https://demo.invalid/wms',
    params: {LAYERS: 'demo:world', TILED: true},
    serverType: 'geoserver',
    wrapX: true,
    transition: 0,
    tileLoadFunction: function (tile, src) {
      var bbox = worldParam(src, 'BBOX').split(',').map(Number);
      var width = parseInt(worldParam(src, 'WIDTH'), 10) || 256;
      var height = parseInt(worldParam(src, 'HEIGHT'), 10) || 256;
      if (bbox.length === 4) {
        tile.getImage().src = worldToURL(width, height, bbox);
      }
    }
  });

  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: 0.55}),
      new ol.layer.Tile({source: wmsSource, opacity: 0.75})
    ],
    view: new ol.View({
      center: ol.proj.fromLonLat([179, 12]),
      zoom: 2
    })
  });

  map.on('moveend', function () {
    var center = ol.proj.toLonLat(map.getView().getCenter());
    document.getElementById('info').textContent =
      '中心经度 ' + center[0].toFixed(2) + '° · wrapX true';
  });

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