cesium加载.tif格式文件

最近项目中有需要直接加载三方给的后缀名tif格式的文件

<script src="https://cdn.jsdelivr.net/npm/geotiff"></script>
或者
yarn add geotiff
npm install geotiff

新建tifs.js

import GeoTIFF, { fromBlob, fromUrl, fromArrayBuffer } from 'geotiff';
import GeoTIFFImage from 'geotiff/dist-node/geotiffimage';
var tiff;
var image;
var rectangle;
class GeoTiffUtil {constructor() {}async init(){this.tiff = await fromUrl('http://xxxx.tif');this.image = await this.tiff.getImage();let [west, south, east, north] = this.image.getBoundingBox();const code =this.image.geoKeys.ProjectedCSTypeGeoKey ||this.image.geoKeys.GeographicTypeGeoKey;let { x: w, y: n } = await (await fetch(`//epsgIo/trans?x=${west}&y=${north}&s_srs=${code}&t_srs=4326`)).json();let { x: e, y: s } = await (await fetch(`//epsgIo/trans?x=${east}&y=${south}&s_srs=${code}&t_srs=4326`)).json();const [red = [], green = [], blue = []] = await this.image.readRasters();// 将像素信息写入canvasconst canvas = document.createElement("canvas");let width = this.image.getWidth();let height = this.image.getHeight();canvas.width = width;canvas.height = height;let ctx = canvas.getContext("2d");let imageData = ctx.createImageData(width, height);for (var i = 0; i < imageData.data.length / 4; i += 1) {imageData.data[i * 4 + 0] = red[i];imageData.data[i * 4 + 1] = green[i] || 0;imageData.data[i * 4 + 2] = blue[i] || 0;imageData.data[i * 4 + 3] = red[i] === 0 ? 0 : 255;}ctx.putImageData(imageData, 0, 0);return {canvas:canvas,rectangle:[w, s, e, n]};}
}
export default new GeoTiffUtil();

index.vue

 import GeoTiffUtil from '@/utils/tifs.js';     GeoTiffUtil.init().then((res)=>{let rectangle = Cesium.Rectangle.fromDegrees(res.rectangle[0], res.rectangle[1],             res.rectangle[2],res.rectangle[3]);let du = res.canvas.toDataURL();viewer.imageryLayers.addImageryProvider(new Cesium.SingleTileImageryProvider({url: du,rectangle,}));viewer.camera.setView({destination: rectangle,});})