vuejs开发组件分享之H5图片上传、压缩及拍照旋转的问题处理

<template>
 <div>
  <input type="file"  id="img-upload" multiple accept="image/*" @change="uploadImg($event)"/>
 </div>
</template>
<script>
 import EXIF from '../../../Resource/Global/Js/exif'
 export default{
  name:"image-html5-upload",
  props:{
   imgArr:{
    type:Array,
    twoWay: true,
    default:Array
   },
   imgNumLimit:{//一次最多可以上传多少张照片
    type:Number,
    default:4
   }
  },
  methods:{
   "uploadImg": function(e){
    let tag = e.target;
    let fileList = tag.files;
    let imgNum = fileList.length;
    let _this = this;
    _this.imgArr = [];//图片数据清零
    if(this.imgArr.length + imgNum > this.imgNumLimit){
     alert('一次最多上传'+this.imgNumLimit+'张图片！');
     return;
    }
    var Orientation;
    for(let i=0;i<imgNum;i++){
     EXIF.getData(fileList[i], function(){
      Orientation = EXIF.getTag(fileList[i], 'Orientation');
     });
     let reader = new FileReader();
     reader.readAsDataURL(fileList[i]);
     reader.onload = function(){
      var oReader = new FileReader();
      oReader.onload = function(e) {
       var image = new Image();
       image.src = e.target.result;
       image.onload = function() {
        var expectWidth = this.naturalWidth;
        var expectHeight = this.naturalHeight;
        if (this.naturalWidth > this.naturalHeight && this.naturalWidth > 800) {
         expectWidth = 800;
         expectHeight = expectWidth * this.naturalHeight / this.naturalWidth;
        } else if (this.naturalHeight > this.naturalWidth && this.naturalHeight > 1200) {
         expectHeight = 1200;
         expectWidth = expectHeight * this.naturalWidth / this.naturalHeight;
        }
        var canvas = document.createElement("canvas");
        var ctx = canvas.getContext("2d");
        canvas.width = expectWidth;
        canvas.height = expectHeight;
        ctx.drawImage(this, 0, 0, expectWidth, expectHeight);
        var base64 = null;
        //修复ios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
           _this.rotateImg(this,'left',canvas);
           break;
          case 8://需要逆时针（向右）90度旋转
           _this.rotateImg(this,'right',canvas);
           break;
          case 3://需要180度旋转
           _this.rotateImg(this,'right',canvas);//转两次
           _this.rotateImg(this,'right',canvas);
           break;
         }
        }
        base64 = canvas.toDataURL("image/jpeg", 0.8);
        if(fileList[i].size / 1024000 > 1){
         _this.imgScale(base64, 4)
        }else{
         _this.imgArr.push({"src": base64});
        }
        console.log(JSON.stringify(_this.imgArr));
       };
      };
      oReader.readAsDataURL(fileList[i]);
     }
    }
   },
   "imgScale": function(imgUrl,quality){
    let img = new Image();
    let _this = this;
    let canvas = document.createElement('canvas');
    let cxt = canvas.getContext('2d');
    img.src = imgUrl;
    img.onload = function(){
     //缩放后图片的宽高
     let width = img.naturalWidth/quality;
     let height = img.naturalHeight/quality;
     canvas.width = width;
     canvas.height = height;
     cxt.drawImage(this, 0, 0, width, height);
     _this.imgArr.push({"src": canvas.toDataURL('image/jpeg')});
    }
   },
   "rotateImg":function (img, direction,canvas) {//图片旋转
    var min_step = 0;
    var max_step = 3;
    if (img == null)return;
    var height = img.height;
    var width = img.width;
    var step = 2;
    if (step == null) {
     step = min_step;
    }
    if (direction == 'right') {
     step++;
     step > max_step && (step = min_step);
    } else {
     step--;
     step < min_step && (step = max_step);
    }
    var degree = step * 90 * Math.PI / 180;
    var 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;
    }
   }
  }
 }
</script>

<template>
 <div>
  <div class="album-img-list">
   <ul>
    <li v-for="img in imgList"><div class="album-bg-img"><img :src='img.src'> </div></li>
   </ul>
  </div>
  <div class="album">
   <label for="img-upload">上传照片</label>
    <image-html5-upload :img-arr.sync="imgList"></image-html5-upload>
  </div>
 </div>
</template>