//这是一个解决exif更改脱方向的一个js文件 // 应用前先npm install exif-js --save或者直接引入exif-js //// 调用方法 // let baseData; // imgExif(file,function (base){ // baseData=base // }); import Exif from 'exif-js' //引入exif let u = {}; // 转换的主体方法 u.index = (file, callback) => { let Orientation, resultData; //图片的方向,返回的值 //去获取拍照时的信息,解决拍出来的照片旋转问题 Exif.getData(file, function () { Orientation = Exif.getTag(this, 'Orientation'); }); // 看支持不支持FileReader if (!file || !window.FileReader) return; // 看支持不支持FileReader if (!file || !window.FileReader) return; if (/^image/.test(file.type)) { // 创建一个reader let reader = new FileReader(); // 将图片2将转成 base64 格式 reader.readAsDataURL(file); // 读取成功后的回调 reader.onloadend = function () { let result = this.result; //判断图片是否有方向值没有直接返回base64 if (!Orientation) { callback(result); } else { let img = new Image(); img.src = result; //图片信息加载完转换方向 img.onload = function () { resultData = u.compress(img, Orientation); callback(resultData); } } } } }; //更改旋转方向 u.compress = (img, Orientation) => { let canvas = document.createElement("canvas"), ctx = canvas.getContext('2d'), tCanvas = document.createElement("canvas"), tctx = tCanvas.getContext("2d"), initSize = img.src.length, width = img.width, height = img.height, ratio = 1; //声明 canvas.width = width; canvas.height = height; // 铺底色 ctx.fillStyle = "#fff"; ctx.fillRect(0, 0, canvas.width, canvas.height); //如果图片像素大于100万则使用瓦片绘制 let count; if ((count = width * height / 1000000) > 1) { // console.log("超过100W像素"); count = ~~(Math.sqrt(count) + 1); //计算要分成多少块瓦片 // 计算每块瓦片的宽和高 let nw = ~~(width / count); let nh = ~~(height / count); tCanvas.width = nw; tCanvas.height = nh; for (let i = 0; i < count; i++) { for (let j = 0; j < count; j++) { tctx.drawImage(img, i * nw * ratio, j * nh * ratio, nw * ratio, nh * ratio, 0, 0, nw, nh); ctx.drawImage(tCanvas, i * nw, j * nh, nw, nh); } } } else { ctx.drawImage(img, 0, 0, width, height); } //修复上传图片的时候被旋转的问题 if (Orientation != "" && Orientation != 1) { switch (Orientation) { case 6://需要顺时针(向左)90度旋转 u.rotateImg(img, 'left', canvas); break; case 8://需要逆时针(向右)90度旋转 u.rotateImg(img, 'right', canvas); break; case 3://需要180度旋转 u.rotateImg(img, 'right', canvas, 2);//转两次 break; } } //进行最小压缩 let ndata = canvas.toDataURL('image/jpeg', 1); tCanvas.width = tCanvas.height = canvas.width = canvas.height = 0; return ndata; }; //更改旋转方向 u.rotateImg = (img, direction, canvas, num) => { //最小与最大旋转方向,图片旋转4次后回到原方向 const min_step = 0; const max_step = 3; if (img == null) return; //img的高度和宽度不能在img元素隐藏后获取,否则会出错 let height = img.height; let width = img.width; let step = 2; if (step == null) { step = min_step; } if (direction == 'right') { step++; //旋转到原位置,即超过最大值 step > max_step && (step = min_step); } else { step--; step < min_step && (step = max_step); } //旋转180度 step = num ? num : step; //旋转角度以弧度值为参数 let degree = step * 90 * Math.PI / 180; let ctx = canvas.getContext('2d'); switch (step) { case 0: canvas.width = width; canvas.height = height; ctx.drawImage(img, 0, 0); break; case 1: canvas.width = height; canvas.height = width; ctx.rotate(degree); ctx.drawImage(img, 0, -height); break; case 2: canvas.width = width; canvas.height = height; ctx.rotate(degree); ctx.drawImage(img, -width, -height); break; case 3: canvas.width = height; canvas.height = width; ctx.rotate(degree); ctx.drawImage(img, -width, 0); break; } }; window.imgExif = u;
就是那么残暴直接上代码
要是后台需要的是file用这个转换一下就可以了
//将base64转换为img文件 u.compress = (img, Orientation) => { let arr = dataurl.split(','), mime = arr[0].match(/:(.*?);/)[1], bstr = atob(arr[1]), n = bstr.length, u8arr = new Uint8Array(n); while (n--) { u8arr[n] = bstr.charCodeAt(n); } return new File([u8arr], filename, {type: mime}); };
为啥少于150字的随笔不能发布到博客我的天呀!!直接代码不是好点吗???我这个说不了那么多话呀,,这好折磨人呀,,