<template>
 <div>
  <input type="file" id="upload" accept="image" @change="upload" />
 </div>
</template>
<script>
export default {
 data() {
  return {
   picValue:{},headerImage:''
  };
 },components: {},methods: {
  upload(e) {
   console.log(e);
   let files = e.target.files || e.dataTransfer.files;
   if (!files.length) return;
   this.picValue = files[0];
   this.imgPreview(this.picValue);
  },imgPreview(file) {
   let self = this;
   let Orientation;
   //去獲取拍照時的資訊，解決拍出來的照片旋轉問題
   self.Exif.getData(file,function() {
    Orientation = self.Exif.getTag(this,'Orientation');
   });
   // 看支援不支援FileReader
   if (!file || !window.FileReader) return;

   if (/^image/.test(file.type)) {
    // 建立一個reader
    let reader = new FileReader();
    // 將圖片2將轉成 base64 格式
    reader.readAsDataURL(file);
    // 讀取成功後的回撥
    reader.onloadend = function() {
     let result = this.result;
     let img = new Image();
     img.src = result;
     //判斷圖片是否大於100K,是就直接上傳，反之壓縮圖片
     if (this.result.length <= 100 * 1024) {
      self.headerImage = this.result;
      self.postImg();
     } else {
      img.onload = function() {
       let data = self.compress(img,Orientation);
       self.headerImage = data;
       self.postImg();
      };
     }
    };
   }
  },compress(img,Orientation) {
   let canvas = document.createElement('canvas');
   let ctx = canvas.getContext('2d');
   //瓦片canvas
   let tCanvas = document.createElement('canvas');
   let tctx = tCanvas.getContext('2d');
   let initSize = img.src.length;
   let width = img.width;
   let height = img.height;
   //如果圖片大於四百萬畫素，計算壓縮比並將大小壓至400萬以下
   let ratio;
   if ((ratio = (width * height) / 4000000) > 1) {
    console.log('大於400萬畫素');
    ratio = Math.sqrt(ratio);
    width /= ratio;
    height /= ratio;
   } else {
    ratio = 1;
   }
   canvas.width = width;
   canvas.height = height;
   //    鋪底色
   ctx.fillStyle = '#fff';
   ctx.fillRect(0,canvas.width,canvas.height);
   //如果圖片畫素大於100萬則使用瓦片繪製
   let count;
   if ((count = (width * height) / 1000000) > 1) {
    console.log('超過100W畫素');
    count = ~~(Math.sqrt(count) + 1); //計算要分成多少塊瓦片
    //      計算每塊瓦片的寬和高
    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,nw,nh
      );
      ctx.drawImage(tCanvas,i * nw,j * nh,nh);
     }
    }
   } else {
    ctx.drawImage(img,width,height);
   }
   //修復ios上傳圖片的時候 被旋轉的問題
   if (Orientation != '' && Orientation != 1) {
    switch (Orientation) {
     case 6: //需要順時針（向左）90度旋轉
      this.rotateImg(img,'left',canvas);
      break;
     case 8: //需要逆時針（向右）90度旋轉
      this.rotateImg(img,'right',canvas);
      break;
     case 3: //需要180度旋轉
      this.rotateImg(img,canvas); //轉兩次
      this.rotateImg(img,canvas);
      break;
    }
   }
   //進行最小壓縮
   let ndata = canvas.toDataURL('image/jpeg',0.1);
   tCanvas.width = tCanvas.height = canvas.width = canvas.height = 0;
   return ndata;
  },rotateImg(img,direction,canvas) {
   //最小與最大旋轉方向，圖片旋轉4次後回到原方向
   const min_step = 0;
   const max_step = 3;
   if (img == null) return;
   //img的高度和寬度不能在img元素隱藏後獲取，否則會出錯
   let height = img.height;
   let width = img.width;
   let step = 2;
   if (step == null) {
    step = min_step;
   }
   if (direction == 'right') {
    step++;
    //旋轉到原位置，即超過最大值
    step > max_step && (step = min_step);
   } else {
    step--;
    step < min_step && (step = max_step);
   }
   //旋轉角度以弧度值為引數
   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);
     break;
    case 1:
     canvas.width = height;
     canvas.height = width;
     ctx.rotate(degree);
     ctx.drawImage(img,-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,0);
     break;
   }
  },postImg() {
   //這裡寫介面
　　　　//列印的圖片base64

   console.log('this.headerImage',this.headerImage);
   //介面 axios
  }
 }
};
</script>

要先執行

npm install exif-js --save

然後在main.js中新增

importExiffrom'exif-js'
Vue.use(Exif)
Vue.prototype.Exif=Exif

以上就是vue使用exif獲取圖片旋轉，壓縮的示例程式碼的詳細內容，更多關於vue 圖片旋轉，壓縮的資料請關注我們其它相關文章！