vue图片压缩，不失真
1.在index.html中引入mobileBUGFix.min.js
// mobileBUGFix.min.js内容见最下面附件
2.在build/webpack.base.conf.js文件中增加：
module.exports = {
externals: {
'MegaPixImage': 'MegaPixImage',
'JPEGEncoder': 'JPEGEncoder'
}
}
3.新建compressImage.js，内容如下：
import MegaPixImage from 'MegaPixImage' import JPEGEncoder from 'JPEGEncoder' // 将base64转换为blob export function convertBase64UrlToBlob(urlData) { var arr = urlData.split(',') var mime = arr[0].match(/:(.*?);/)[1] var bstr = atob(arr[1]) var n = bstr.length var u8arr = new Uint8Array(n) while (n--) { u8arr[n] = bstr.charCodeAt(n) } return new Blob([u8arr], { type: mime }) } // 压缩图片 export function compressImage(path, config) { return new Promise((resolve, reject) => { // 生成canvas var canvas = document.createElement('canvas') var ctx = canvas.getContext('2d') var img = new Image() img.crossOrigin = 'Anonymous' img.onload = function() { var that = this var w = that.width var h = that.height var scale = w / h w = config.width || config.height * scale || w h = config.height || config.width / scale || h // 最大宽高如有限制时的处理 w = config.maxWidth && w > config.maxWidth ? config.maxWidth : w h = config.maxHeight && h > config.maxHeight ? config.maxHeight : h w = Math.min(w, h * scale) || w h = Math.min(h, w / scale) || h var quality = 0.7 // 默认图片质量为0.7 // 创建属性节点 var anw = document.createAttribute('width') anw.nodeValue = w var anh = document.createAttribute('height') anh.nodeValue = h canvas.setAttributeNode(anw) canvas.setAttributeNode(anh) ctx.drawImage(that, 0, 0, w, h) if (config.quality && config.quality <= 1 && config.quality > 0) { quality = config.quality } var base64 = canvas.toDataURL('image/jpeg', quality) // 在指定图片格式为 image/jpeg 或 image/webp的情况下，可以从 0 到 1 的区间内选择图片的质量。如果超出取值范围，将会使用默认值 0.92。其他参数会被忽略。 // 修复IOS if (navigator.userAgent.match(/iphone/i)) { var mpImg = new MegaPixImage(img) mpImg.render(canvas, { maxWidth: w, maxHeight: h, quality: quality }) base64 = canvas.toDataURL('image/jpeg', quality) } // 修复android if (navigator.userAgent.match(/Android/i)) { var encoder = new JPEGEncoder() base64 = encoder.encode(ctx.getImageData(0, 0, w, h), quality * 100) } // var blob = convertBase64UrlToBlob(base64) // 回调函数返回base64的值，也可根据自己的需求返回blob的值 // base64 = base64.substr(base64.indexOf(',') + 1) // 去掉base64前面的部分 resolve(base64) canvas = null } img.src = path }) }
4.使用
// 引入 import { compressImage } from './compressImage' // 具体路径按自己存放的位置而定 // 调用 compressImage(图片路径, { maxWidth: 1920, // 限制最大宽度 maxHeight: 1080, // 限制最大高度，若宽高都限制了，按原图比例最小边为主 width: 100, // 压缩后图片的宽 height: 200, // 压缩后图片的高，宽高若只传一个，则按图片原比例进行压缩 quality: 0.8 // 压缩后图片的清晰度，取值0-1，值越小，所绘制出的图像越模糊 }).then(result => { console.log(result) // result即为压缩后的结果 })
附件：
mobileBUGFix.min.js
/* jpeg_encoder_basic.js for android jpeg压缩质量修复 */
function JPEGEncoder(a){function I(a){var c,i,j,k,l,m,n,o,p,b=[16,11,10,16,24,40,51,61,12,12,14,19,26,58,60,55,14,13,16,24,40,57,69,56,14,17,22,29,51,87,80,62,18,22,37,56,68,109,103,77,24,35,55,64,81,104,113,92,49,64,78,87,103,121,120,101,72,92,95,98,112,100,103,99];for(c=0;64>c;c++)i=d((b[c]*a+50)/100),1>i?i=1:i>255&&(i=255),e[z[c]]=i;for(j=[17,18,24,47,99,99,99,99,18,21,26,66,99,99,99,99,24,26,56,99,99,99,99,99,47,66,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99],k=0;64>k;k++)l=d((j[k]*a+50)/100),1>l?l=1:l>255&&(l=255),f[z[k]]=l;for(m=[1,1.387039845,1.306562965,1.175875602,1,.785694958,.5411961,.275899379],n=0,o=0;8>o;o++)for(p=0;8>p;p++)g[n]=1/(8*e[z[n]]*m[o]*m[p]),h[n]=1/(8*f[z[n]]*m[o]*m[p]),n++}function J(a,b){var f,g,c=0,d=0,e=new Array;for(f=1;16>=f;f++){for(g=1;g<=a[f];g++)e[b[d]]=[],e[b[d]][0]=c,e[b[d]][1]=f,d++,c++;c*=2}return e}function K(){i=J(A,B),j=J(E,F),k=J(C,D),l=J(G,H)}function L(){var 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/* megapix-image.js for IOS(iphone5+) drawImage画面扭曲修复 */
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