cesium 添加监听事件、获取中心点坐标、高度、当前可视化区域范围

程序员文章站 2022-05-27 14:37:36
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<!DOCTYPE html>
<html lang="en">

<head>
  <!-- Use correct character set. -->
  <meta charset="utf-8">
  <!-- Tell IE to use the latest, best version. -->
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <!-- Make the application on mobile take up the full browser screen and disable user scaling. -->
  <meta name="viewport"
    content="width=device-width, initial-scale=1, maximum-scale=1, minimum-scale=1, user-scalable=no">
  <title>天地图</title>
  <script src="../Build/Cesium/Cesium.js"></script>
  <style>
    @import url(../Build/Cesium/Widgets/widgets.css);

    html,
    body,
    #cesiumContainer {
      width: 100%;
      height: 100%;
      margin: 0;
      padding: 0;
      overflow: hidden;
    }
  </style>
</head>

<body>
  <div id="cesiumContainer"></div>
  <script>
    var token = "0b018552994f71a9467d24461a8f8238";
    var viewer = new Cesium.Viewer('cesiumContainer', {
      animation: false, //是否创建动画小器件，左下角仪表
      baseLayerPicker: false, //是否显示图层选择器
      fullscreenButton: false, //是否显示全屏按钮
      geocoder: false, //是否显示geocoder小器件，右上角查询按钮  
      homeButton: false, //是否显示Home按钮
      infoBox: false, //是否显示信息框
      sceneModePicker: false, //是否显示3D/2D选择器
      selectionIndicator: false, //是否显示选取指示器组件
      timeline: false, //是否显示时间轴
      navigationHelpButton: false, //是否显示右上角的帮助按钮
      scene3DOnly: true, //如果设置为true，则所有几何图形以3D模式绘制以节约GPU资源
      imageryProvider: new Cesium.WebMapTileServiceImageryProvider({
        url: "http://t0.tianditu.gov.cn/img_w/wmts?service=wmts&request=GetTile&version=1.0.0&LAYER=img&tileMatrixSet=w&TileMatrix={TileMatrix}&TileRow={TileRow}&TileCol={TileCol}&style=default&format=tiles&tk=" +
          token,
        layer: "tdtImgBasicLayer",
        style: "default",
        format: "image/jpeg",
        show: false
      })
    });
    viewer.imageryLayers.addImageryProvider(new Cesium.WebMapTileServiceImageryProvider({
      url: "http://t0.tianditu.gov.cn/cia_w/wmts?service=wmts&request=GetTile&version=1.0.0&LAYER=cia&tileMatrixSet=w&TileMatrix={TileMatrix}&TileRow={TileRow}&TileCol={TileCol}&style=default&format=tiles&tk=" +
        token,
      layer: "tdtImgAnnoLayer",
      style: "default",
      format: "image/jpeg",
      tileMatrixSetID: "GoogleMapsCompatible",
      show: false
    }));

    /* 三维球转动添加监听事件 */
    viewer.camera.changed.addEventListener(function (percentage) {
        getCenterPosition();
        getCurrentExtent();
        // 打印中心点坐标、高度、当前范围坐标
        console.log(getCenterPosition());
        console.log("bounds",getCurrentExtent());
    });

    /* 获取camera高度  */
    function getHeight() {
      if (viewer) {
        var scene = viewer.scene;
        var ellipsoid = scene.globe.ellipsoid;
        var height = ellipsoid.cartesianToCartographic(viewer.camera.position).height;
        return height;
      }
    }

    /* 获取camera中心点坐标 */
    function getCenterPosition() {
      var result = viewer.camera.pickEllipsoid(new Cesium.Cartesian2(viewer.canvas.clientWidth / 2, viewer.canvas
        .clientHeight / 2));
      var curPosition = Cesium.Ellipsoid.WGS84.cartesianToCartographic(result);
      var lon = curPosition.longitude * 180 / Math.PI;
      var lat = curPosition.latitude * 180 / Math.PI;
      var height = getHeight();
      return {
        lon: lon,
        lat: lat,
        height: height
      };
    }

    function getCurrentExtent() {
        // 范围对象
        var extent = {};

        // 得到当前三维场景
        var scene = viewer.scene;

        // 得到当前三维场景的椭球体
        var ellipsoid = scene.globe.ellipsoid;
        var canvas = scene.canvas;

        // canvas左上角
        var car3_lt = viewer.camera.pickEllipsoid(new Cesium.Cartesian2(0, 0), ellipsoid);

        // canvas右下角
        var car3_rb = viewer.camera.pickEllipsoid(new Cesium.Cartesian2(canvas.width, canvas.height), ellipsoid);

        // 当canvas左上角和右下角全部在椭球体上
        if (car3_lt && car3_rb) {
            var carto_lt = ellipsoid.cartesianToCartographic(car3_lt);
            var carto_rb = ellipsoid.cartesianToCartographic(car3_rb);
            extent.xmin = Cesium.Math.toDegrees(carto_lt.longitude);
            extent.ymax = Cesium.Math.toDegrees(carto_lt.latitude);
            extent.xmax = Cesium.Math.toDegrees(carto_rb.longitude);
            extent.ymin = Cesium.Math.toDegrees(carto_rb.latitude);
        }

        // 当canvas左上角不在但右下角在椭球体上
        else if (!car3_lt && car3_rb) {
            var car3_lt2 = null;
            var yIndex = 0;
            do {
                // 这里每次10像素递加，一是10像素相差不大，二是为了提高程序运行效率
                yIndex <= canvas.height ? yIndex += 10 : canvas.height;
                car3_lt2 = viewer.camera.pickEllipsoid(new Cesium.Cartesian2(0, yIndex), ellipsoid);
            } while (!car3_lt2);
            var carto_lt2 = ellipsoid.cartesianToCartographic(car3_lt2);
            var carto_rb2 = ellipsoid.cartesianToCartographic(car3_rb);
            extent.xmin = Cesium.Math.toDegrees(carto_lt2.longitude);
            extent.ymax = Cesium.Math.toDegrees(carto_lt2.latitude);
            extent.xmax = Cesium.Math.toDegrees(carto_rb2.longitude);
            extent.ymin = Cesium.Math.toDegrees(carto_rb2.latitude);
        }

        // 获取高度
        extent.height = Math.ceil(viewer.camera.positionCartographic.height);
        return extent;
    }
  </script>
</body>

</html>