CesiumJS 案例 P37：图片图层视角恢复、指定长宽的图片图层视角恢复（原点为图片图层的中心点）
CesiumJS
- CesiumJS 是一个开源的 JavaScript 库，它用于在网页中创建和控制 3D 地球仪（地图）
-
CesiumJS 官网：https://www.cesium.com/
-
CesiumJS 下载地址：https://www.cesium.com/platform/cesiumjs/
-
CesiumJS API 文档：https://cesium.com/learn/cesiumjs/ref-doc/index.html
图片图层视角恢复
doctype html>
<html lang="en">
<head>
<meta charset="UTF-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<title>ImageryProvider - 图片图层视角恢复title>
<link rel="stylesheet" href="../js/Cesium-1.112/Build/Cesium/Widgets/widgets.css" />
<style>
* {
margin: 0;
padding: 0;
box-sizing: border-box;
}
html,
body {
width: 100%;
height: 100%;
}
.container {
width: 100%;
height: 100%;
}
.btn-reset-view {
position: fixed;
left: 0px;
top: 0px;
}
style>
head>
<body>
<div id="container">div>
<button class="btn-reset-view">恢复默认视角button>
body>
<script src="../js/Cesium-1.112/Build/Cesium/Cesium.js">script>
<script>
const viewer = new Cesium.Viewer("container");
const west = 0; // 西经（西经为负）
const south = 0; // 南纬（南纬为负）
const east = 10; // 东经（东经为正）
const north = 10; // 北纬（北纬为正）
// 创建图片图层
const imageryProvider = new Cesium.SingleTileImageryProvider({
url: "../img/test.jpg",
rectangle: Cesium.Rectangle.fromDegrees(west, south, east, north),
});
const imageryLayer = viewer.imageryLayers.addImageryProvider(imageryProvider);
const resetView = () => {
viewer.camera.flyTo({
destination: Cesium.Cartesian3.fromDegrees((west + east) / 2, (south + north) / 2, 1000000),
duration: 2.0,
});
};
const btnResetView = document.querySelector(".btn-reset-view");
btnResetView.addEventListener("click", resetView);
resetView();
script>
html>
指定长宽的图片图层视角恢复（原点为图片图层的中心点）
doctype html>
<html lang="en">
<head>
<meta charset="UTF-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<title>ImageryProvider - 指定长宽的图片图层视角恢复（原点为图片图层的中心点）title>
<link rel="stylesheet" href="../js/Cesium-1.112/Build/Cesium/Widgets/widgets.css" />
<style>
* {
margin: 0;
padding: 0;
box-sizing: border-box;
}
html,
body {
width: 100%;
height: 100%;
}
.container {
width: 100%;
height: 100%;
}
.btn-reset-view {
position: fixed;
left: 0px;
top: 0px;
}
style>
head>
<body>
<div id="container">div>
<button class="btn-reset-view">恢复默认视角button>
body>
<script src="../js/Cesium-1.112/Build/Cesium/Cesium.js">script>
<script>
const viewer = new Cesium.Viewer("container");
// offset：偏移量（米）
// offset.x：X 轴偏移，东方向偏移
// offset.y：Y 轴偏移，北方向偏移
function transformCoordinate(origin, offset) {
offset.x = -offset.x;
// 将原点经纬度转换为弧度
const originLongitudeRadians = Cesium.Math.toRadians(origin.longitude);
const originLatitudeRadians = Cesium.Math.toRadians(origin.latitude);
// 创建原点的 Cartographic 对象
const originCartographic = new Cesium.Cartographic(originLongitudeRadians, originLatitudeRadians);
// 将原点的 Cartographic 对象转换为笛卡尔坐标
const originCartesian = Cesium.Ellipsoid.WGS84.cartographicToCartesian(originCartographic);
// 创建偏移量的 Cartesian3 对象，偏移量在东和北方向
const east = new Cesium.Cartesian3(offset.x, 0, 0);
const north = new Cesium.Cartesian3(0, offset.y, 0);
// 将偏移量投影到地球表面上
const surfaceNormal = Cesium.Cartesian3.normalize(originCartesian, new Cesium.Cartesian3());
const eastSurface = Cesium.Cartesian3.cross(surfaceNormal, Cesium.Cartesian3.UNIT_Z, new Cesium.Cartesian3());
const northSurface = Cesium.Cartesian3.cross(eastSurface, surfaceNormal, new Cesium.Cartesian3());
Cesium.Cartesian3.normalize(eastSurface, eastSurface);
Cesium.Cartesian3.normalize(northSurface, northSurface);
const offsetEast = Cesium.Cartesian3.multiplyByScalar(eastSurface, offset.x, new Cesium.Cartesian3());
const offsetNorth = Cesium.Cartesian3.multiplyByScalar(northSurface, offset.y, new Cesium.Cartesian3());
// 将投影的偏移量加到原点的笛卡尔坐标上
const newCartesian = Cesium.Cartesian3.add(originCartesian, Cesium.Cartesian3.add(offsetEast, offsetNorth, new Cesium.Cartesian3()), new Cesium.Cartesian3());
// 将新的笛卡尔坐标转换回经纬度坐标
const newCartographic = Cesium.Ellipsoid.WGS84.cartesianToCartographic(newCartesian);
// 将弧度转换回角度
const newLongitude = Cesium.Math.toDegrees(newCartographic.longitude);
const newLatitude = Cesium.Math.toDegrees(newCartographic.latitude);
return {
longitude: newLongitude,
latitude: newLatitude,
};
}
// 图片图层的长宽
const imageWidth = 200; // 单位为米
const imageHeight = 100; // 单位为米
// 图片图层的原点
const originLongitude = 0; // 原点经度
const originLatitude = 0; // 原点纬度
const result = transformCoordinate(
{
longitude: originLongitude,
latitude: originLatitude,
},
{
x: imageWidth / 2,
y: imageHeight / 2,
},
);
const west = originLongitude - result.longitude; // 西经（西经为负）
const south = originLatitude - result.latitude; // 南纬（南纬为负）
const east = originLongitude + result.longitude; // 东经（东经为正）
const north = originLatitude + result.latitude; // 北纬（北纬为正）
// 创建图片图层
const imageryProvider = new Cesium.SingleTileImageryProvider({
url: "../img/test.jpg",
rectangle: Cesium.Rectangle.fromDegrees(west, south, east, north),
});
viewer.imageryLayers.addImageryProvider(imageryProvider);
// 添加一个点表示原点
const entity = viewer.entities.add({
position: Cesium.Cartesian3.fromDegrees(originLongitude, originLatitude),
point: {
pixelSize: 5,
color: new Cesium.Color(0, 1, 0, 1),
},
});
// ----------------------------------------------------------------------------------------------------
const reset = () => {
viewer.camera.flyTo({
destination: Cesium.Cartesian3.fromDegrees(originLongitude, originLatitude, imageWidth < imageHeight ? imageWidth : imageHeight),
duration: 2.0,
});
};
const btnResetView = document.querySelector(".btn-reset-view");
btnResetView.addEventListener("click", reset);
reset();
script>
html>
