element-ui 图片压缩上传

picture.js

export const compressImgNew = (file) => {return new Promise(resolve => {const reader = new FileReader()const image = new Image()image.onload = (imageEvent) => {const canvas = document.createElement('canvas') // 创建画布const context = canvas.getContext('2d')         // 画布为2d// const width = image.width / 1.05        // 图片宽度 / 压缩比例// const height = image.height / 1.05        // 图片高度 / 压缩比例const width = image.width / 3       // 图片宽度 / 压缩比例const height = image.height / 3       // 图片高度 / 压缩比例canvas.width = width                            // 画布宽度canvas.height = height                          // 画布宽度context.clearRect(0, 0, width, height)context.drawImage(image, 0, 0, width, height)const dataUrl = canvas.toDataURL(file.type)     //图片转路径const blobData = dataURLtoBlob(dataUrl, file.type) //图片转二进制resolve(blobData)}reader.onload = e => { image.src = e.target.result }reader.readAsDataURL(file)})
};//图片转二进制
function dataURLtoBlob(dataURL, type) {var binary = atob(dataURL.split(',')[1])var array = []for (var i = 0; i < binary.length; i++) {array.push(binary.charCodeAt(i))}return new Blob([new Uint8Array(array)], { type: type })
}

使用

import { compressImgNew } from “@/assets/js/picture.js”;

    beforeAvatarUpload(file) {let types = ["image/jpeg","image/jpg","image/png"];const isImage = types.includes(file.type);const isLtSize = file.size / 1024 / 1024 < 5;if (!isImage) {this.$message.warning("上传图片只能是 JPG、JPEG、PNG 格式!");return false;}if (!isLtSize) {this.$message.warning("上传图片大小不能超过 5MB!");return false;}return compressImgNew(file);},