Cog Modeltransformation

<!--
  说明：仿射参数与图像旋转的中文示例，数据在页面内生成，可独立运行。
  核心逻辑：atan2(B, A) 求旋转 + 向量模求缩放 + 角点变换绘制范围
  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>仿射参数与图像旋转</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 button{font:inherit;padding:3px 9px;border:1px solid #c9ced6;background:#fff;
       border-radius:5px;cursor:pointer;color:#333}
  .bar button:hover{background:#eef2f8}
  .bar input[type=range]{width:110px;vertical-align:middle}
  .bar input[type=text]{font:inherit;padding:2px 6px;border:1px solid #c9ced6;border-radius:4px}
  #map{flex:1 1 auto;min-height:0;background:#eef0f3;position:relative}
  .panel{flex:0 0 auto;max-height:34%;overflow:auto;padding:8px 12px;font-size:12px;
       background:#fff;border-top:1px solid #e3e6ea;color:#3d4451}
  .panel pre{margin:0;font-family:Consolas,"Courier New",monospace;font-size:11px;
       white-space:pre-wrap;word-break:break-all;line-height:1.5}
  .ol-attribution{font-size:11px}

</style>
</head>
<body>
<div class="bar">
<label>横向缩放 A <input type="range" id="pa" min="40" max="200" value="120"></label>
<label>错切 B <input type="range" id="pb" min="-100" max="100" value="35"></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') {
    var errBox = document.getElementById('map');
    if (errBox) {
      errBox.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;
  var W = 128;
  var canvas = document.createElement('canvas');
  canvas.width = canvas.height = W;
  var ctx = canvas.getContext('2d');
  ctx.fillStyle = '#eaf1fb';
  ctx.fillRect(0, 0, W, W);
  ctx.strokeStyle = '#a9bed6';
  ctx.lineWidth = 1;
  for (var i = 0; i <= W; i += 16) {
    ctx.beginPath(); ctx.moveTo(i, 0); ctx.lineTo(i, W); ctx.stroke();
    ctx.beginPath(); ctx.moveTo(0, i); ctx.lineTo(W, i); ctx.stroke();
  }
  ctx.fillStyle = '#1f5fd0';
  ctx.fillRect(0, 0, 28, W);
  ctx.fillStyle = '#ee602a';
  ctx.fillRect(0, 0, W, 20);
  var imageUrl = canvas.toDataURL('image/png');

  var center = [116.397, 39.909];
  var feature = new ol.Feature({geometry: new ol.geom.Point(fromLonLat(center))});
  var footprint = new ol.Feature({geometry: new ol.geom.Polygon([])});

  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'})}),
      new ol.layer.Vector({
        source: new ol.source.Vector({features: [footprint]}),
        style: new ol.style.Style({
          fill: new ol.style.Fill({color: 'rgba(31,95,208,0.08)'}),
          stroke: new ol.style.Stroke({color: '#1f5fd0', width: 1.5, lineDash: [5, 4]})
        })
      }),
      new ol.layer.Vector({source: new ol.source.Vector({features: [feature]})})
    ],
    view: new ol.View({center: fromLonLat(center), zoom: 12}),
    controls: ol.control.defaults.defaults({attribution: false, zoom: true, rotate: false})
  });

  var pa = document.getElementById('pa');
  var pb = document.getElementById('pb');
  var info = document.getElementById('info');

  function apply() {
    var A = +pa.value / 100;
    var B = +pb.value / 100;
    var scale = Math.sqrt(A * A + B * B);
    var angle = Math.atan2(B, A);

    feature.setStyle(new ol.style.Style({
      image: new ol.style.Icon({
        src: imageUrl,
        anchor: [0.5, 0.5],
        scale: scale * 1.6,
        rotation: -angle
      })
    }));

    /* 单位方格四角经 [A B; -B A] 变换后，换算成经纬度画覆盖范围 */
    var half = 0.05;
    var ring = [];
    [[-1, -1], [1, -1], [1, 1], [-1, 1], [-1, -1]].forEach(function (uv) {
      var u = uv[0];
      var v = uv[1];
      var dx = (A * u + B * v) * half;
      var dy = (-B * u + A * v) * half;
      ring.push(fromLonLat([center[0] + dx, center[1] + dy]));
    });
    footprint.getGeometry().setCoordinates([ring]);

    info.textContent = 'A=' + A.toFixed(2) + ' B=' + B.toFixed(2) +
      ' · 旋转 ' + (angle * 180 / Math.PI).toFixed(1) + '° · 缩放 ' + scale.toFixed(2);
  }

  pa.addEventListener('input', apply);
  pb.addEventListener('input', apply);
  apply();
})();
</script>
</body>
</html>