vue 拍照上传

vue 拍照上传 涉及技术点 canvas裁剪 base64 blob数据装换 forData 数据传递 ，还有hammer.js和exif-js具体代码如下

<template>
    <div class="pic">
        <div class="bg-box">
            <div class="img-box">
                <img src="../../assets/img/news_bg.png" width="100%" alt="">
            </div>
            <div class="headers">
                    <van-nav-bar title="个人信息" @click-left="onClickLeft" >
                        <img class="img" src="../..//assets/img/[e-mail]" slot="left" alt="">
                    </van-nav-bar>
            </div>           
        </div>
        <form enctype="multipart/form-data" >
          <div class="uploadBox">
              <!--主编辑器canvas-->
              <canvas id="canvas" :width="windowWidth" :height="windowWidth"></canvas>
              <!--蒙层canvas-->
              <canvas id="canvasMask" :width="windowWidth" :height="windowWidth"></canvas>
              <!--用于导出图片的canvas-->
              <canvas id="resultImg" width="160" height="160" style="display: none"></canvas>
              <label class="uploadBar" for="uploadInput" v-if="uploadBarShow">
                  <input type="file"
                        style="display: none"
                        id="uploadInput"
                        accept="image/*"
                        ref="file"
                        @change="upLoadChange">
                  <span>点击上传</span>
                  
              </label>
          </div>
          <!-- <img :src="src" v-if="src"/> -->
          <div class="select-box" v-if="!uploadBarShow">
            <!-- <input type="submit"  class="sure-bt"  @click="crop" value="确定裁切"> -->
            <div class="sure-bt"  @click="crop" >确定裁切</div>
            <div class="cancel-bt"  @click="cancel">取消</div>
          </div>
        </form>
        
    </div>
</template>

<script>
import {Toast} from "vant";
import axios from "axios";
import { dataURItoBlob } from "../../assets/js/blob.js"
import { mapMutations } from "vuex";
require("@/assets/plugin/hammer.min"); //引入hammerJS
import qs from "qs"
import EXIF from "exif-js";

export default {
  name: "home",
  data() {
    return {
      src: "",
      orientation: null, //图片元信息
      degree: 0, //原图片旋转角度
      windowWidth: 0, //屏幕的宽度
      imgEl: null,
      imgWidth: 0, //图片的宽度
      imgHeight: 0, //图片的高度
      transWidth: 0, //改变后的图片宽度
      transHeight: 0, //改变后的图片高度
      initScale: 0,
      transformScale: 1, //初始缩放
      prevX: 0, //上一次的X轴
      prevY: 0, //上一次的Y轴
      translateX: 0, //平移X轴
      translateY: 0, //平移Y轴
      uploadBarShow: true, //上传按钮显示
      canvas: null, //canvas
      canvasMask: null, //canvas-mask
      canvasResult: null, //裁切图片canvas
      eq_types : "iOS"
    };
  },
  methods: {
    ...mapMutations([
      'header_pic_update'
    ]),
    onClickLeft() {
      this.$router.go(-1);
    },
    cancel() {
      this.$router.go(-1);
    },
    /**
     * 上传图片
     * */
    upLoadChange() {
      
      let files = this.$refs.file.files[0],
        
        self = this;
        let val = this.$refs.file.value; 
        // console.log("文件是：",files);
        // console.log("文件是：",val);
        
       
      /*控制图片上传大小不超过1MB*/
      if (files.size > 8388608) {
        alert("图片不能超过1MB大小");
        return false;
      }

      /*用EXIF获取图片元信息*/
      EXIF.getData(files, function() {
        self.orientation = EXIF.getTag(this, "Orientation");
      });

      let fr = new FileReader();

      // 监听reader对象的的onload事件，当图片加载完成时，把base64编码賦值给预览图片
      fr.addEventListener(
        "load",
        () => {
          if (this.orientation) {
            /*需要对ios做一下兼容*/
            this.getImgData(fr.result, this.orientation, data => {
              this.createCanvas(data); //初始化canvas
            });
          } else {
            this.createCanvas(fr.result); //初始化canvas
          }
        },
        false
      );
      fr.readAsDataURL(files);
    },

    /**
     * 初始化canvas
     * */
    createCanvas(imgBase64) {
      this.imgEl = new Image();
      this.imgEl.src = imgBase64;

      this.imgEl.onload = () => {
        this.imgWidth = this.imgEl.width; //初始化图片的宽
        this.imgHeight = this.imgEl.height; //初始化图片的高

        // 画蒙层
        this.canvasMask.globalCompositeOperation = "source-out";
        this.canvasMask.fillStyle = "rgb(255,255,255)";
        this.canvasMask.arc(
          this.windowWidth / 2,
          this.windowWidth / 2,
          80,
          0,
          2 * Math.PI
        );
        this.canvasMask.fill();
        this.canvasMask.fillStyle = "rgba(0,0,0,0.7)";
        this.canvasMask.fillRect(0, 0, this.windowWidth, this.windowWidth);

        // 当图片比canvas小时不做任何改变
        if (
          this.imgEl.width < this.windowWidth &&
          this.imgEl.height < this.windowWidth
        ) {
          this.imgWidth = this.imgEl.width;
          this.imgHeight = this.imgEl.height;
        } else {
          //原图片宽高比例 大于 图片框宽高比例
          if (1 <= this.imgEl.width / this.imgEl.height) {
            this.imgWidth = this.windowWidth; //以框的宽度为标准
            this.imgHeight =
              this.windowWidth * (this.imgEl.height / this.imgEl.width);
          } else {
            //原图片宽高比例 小于 图片框宽高比例
            this.imgWidth =
              this.windowWidth * (this.imgEl.width / this.imgEl.height);
            this.imgHeight = this.windowWidth; //以框的高度为标准
          }
        }

        this.canvas.translate(this.windowWidth / 2, this.windowWidth / 2); //把canvas原点移动到中心位置
        this.canvas.drawImage(
          this.imgEl,
          0 - this.imgWidth / 2,
          0 - this.imgHeight / 2,
          this.imgWidth,
          this.imgHeight
        );

        /*初始化hammer*/
        this.initHammer();
      };
    },

    /**
     * @param {string} img 图片的base64
     * @param {int} dir exif获取的方向信息
     * @param {function} next 回调方法，返回校正方向后的base64
     * */
    getImgData(img, dir, next) {
      let image = new Image();
      image.src = img;

      image.onload = function() {
        let degree = 0,
          drawWidth,
          drawHeight,
          width,
          height;
        drawWidth = image.naturalWidth; //暂存图片的宽
        drawHeight = image.naturalHeight; //暂存图片的高

        //以下改变一下图片大小
        let maxSide = Math.max(drawWidth, drawHeight);
        console.log(maxSide);
        if (maxSide > 4032) {
          let minSide = Math.min(drawWidth, drawHeight);
          minSide = minSide / maxSide * 4032;
          maxSide = 4032;
          if (drawWidth > drawHeight) {
            drawWidth = maxSide;
            drawHeight = minSide;
          } else {
            drawWidth = minSide;
            drawHeight = maxSide;
          }
        }

        let canvas = document.createElement("canvas");
        canvas.width = width = drawWidth;
        canvas.height = height = drawHeight;
        let context = canvas.getContext("2d");
        //判断图片方向，重置canvas大小，确定旋转角度，iphone默认的是home键在右方的横屏拍摄方式
        switch (dir) {
          //iphone横屏拍摄，此时home键在左侧
          case 3:
            degree = 180;
            drawWidth = -width;
            drawHeight = -height;
            break;

          //iphone竖屏拍摄，此时home键在下方(正常拿手机的方向)
          case 6:
            canvas.width = height;
            canvas.height = width;
            degree = 90;
            drawWidth = width;
            drawHeight = -height;
            break;

          //iphone竖屏拍摄，此时home键在上方
          case 8:
            canvas.width = height;
            canvas.height = width;
            degree = 270;
            drawWidth = -width;
            drawHeight = height;
            break;
        }

        //使用canvas旋转校正
        context.rotate(degree * Math.PI / 180);
        context.drawImage(this, 0, 0, drawWidth, drawHeight);

        //返回校正图片
        next(canvas.toDataURL("image/jpeg"));
      };
    },

    /**
     * 初始化hammer
     * */
    initHammer() {
      //隐藏上传bar
      this.uploadBarShow = false;

      let hammer = new Hammer(document.querySelector("#canvasMask"));
      hammer.get("pinch").set({ enable: true });
      hammer.get("rotate").set({ enable: true });

      /*缩放 */
      hammer.on("pinchmove pinchstart pinchin pinchout", e => {
        if (e.type === "pinchstart") {
          this.initScale = this.transformScale || 1;
        }
        this.transformScale = this.initScale * e.scale;
        this.canvas.clearRect(
          0 - this.windowWidth / 2,
          0 - this.windowWidth / 2,
          this.windowWidth,
          this.windowWidth
        );
        this.transWidth = this.imgWidth * this.transformScale;
        this.transHeight = this.imgHeight * this.transformScale;
        this.canvas.drawImage(
          this.imgEl,
          this.translateX - this.transWidth / 2,
          this.translateY - this.transHeight / 2,
          this.transWidth,
          this.transHeight
        );
      });

      /*平移*/
      hammer.on("panstart panmove", e => {
        if (e.type === "panstart") {
          this.prevX = this.translateX;
          this.prevY = this.translateY;
        }
        this.translateX = this.prevX + e.deltaX;
        this.translateY = this.prevY + e.deltaY;

        /*擦除canvas*/
        this.canvas.clearRect(
          0 - this.windowWidth / 2,
          0 - this.windowWidth / 2,
          this.windowWidth,
          this.windowWidth
        );
        this.canvas.drawImage(
          this.imgEl,
          this.translateX - (this.transWidth || this.imgWidth) / 2,
          this.translateY - (this.transHeight || this.imgHeight) / 2,
          this.transWidth || this.imgWidth,
          this.transHeight || this.imgHeight
        );
      });
    },

    /**
     * 裁切
     * */
    crop() {
      let base64 = document.querySelector("#canvas").toDataURL("image/png");
      let nImg = new Image();
      nImg.src = base64;

      nImg.onload = () => {
        this.canvasResult.fillStyle = "white";
        this.canvasResult.fillRect(0, 0, 160, 160);
        this.canvasResult.drawImage(
          nImg,
          -(this.windowWidth / 2 - 80),
          -(this.windowWidth / 2 - 80)
        );
        /*最后导出裁切好的图片为base64码*/
        //**将base64传给后台 */
        this.src = document.querySelector("#resultImg").toDataURL("image/jpeg");
        // 将base64转成blob
        let upload_imgs = dataURItoBlob(this.src)
        console.log(upload_imgs, "base64:-->"+this.src);
        
        let formData = new FormData();
        formData.append('action', "edit_user_pic");
        formData.append('files', upload_imgs, 'image.jpeg');
        //有些苹果不支持get方法
        // console.log(formData);
        // console.log(formData.get('action'));
        // console.log(formData.get('files'));
         
        //添加请求头
        axios({
              headers: {
                  'Content-Type':'multipart/form-data'
              },
              method: 'post',
              url: '/api/fileApi',
              data: formData
        })
        .then(res =>{
          console.log(res);
          if(res._code !== "99999"){
            Toast({
              message : res._msg,
              duration : 2500
            });
            return;
          };
          this.header_pic_update(res._result.userPic);
          this.$router.go(-1);

          
        })

        
      };
    }
  },
  mounted() {
    let canvas = document.querySelector("#canvas"),
      canvasMask = document.querySelector("#canvasMask"),
      canvasRsut = document.querySelector("#resultImg");
    this.canvas = canvas.getContext("2d");
    this.canvasMask = canvasMask.getContext("2d");
    this.canvasResult = canvasRsut.getContext("2d");
    this.windowWidth = window.innerWidth;
  },
  created(){
        let u = navigator.userAgent;
        if (u.indexOf("Android") > -1 || u.indexOf("Linux") > -1) {
          //安卓手机
          this.eq_types = "android";
        } else if (u.indexOf("iPhone") > -1) {
          //苹果手机
          this.eq_types = "iOS";
        } else if (u.indexOf("Windows Phone") > -1) {
          //winphone手机
        }
  }
};
</script>

<style lang="less" scoped>
.pic {
  position: relative;
  height: 100vh;
  .bg-box {
    position: relative;
    height: 139px;
    .img-box {
      position: absolute;
      top: 0;
      left: 0;
      z-index: -5;
      width: 100%;
    }
    .headers {
      padding-top: 57px;
      margin: 0 44px;
      /deep/ .van-hairline--bottom {
        background: transparent;
        color: #fff;
        height: 55px;
        line-height: 55px;
      }
      /deep/ .van-nav-bar__left {
        top: 0;
      }
      /deep/ .van-nav-bar__title {
        font-size: 36px;
      }
      /deep/ .van-hairline--bottom::after {
        border: none;
      }
      .img {
        width: 55px;
        height: 55px;
      }
    }
  }
}

* {
  padding: 0;
  margin: 0;
}

.uploadBox {
  position: relative;
}

#canvasMask {
  position: absolute;
  left: 0;
  top: 0;
  z-index: 5;
}

.uploadBar {
  position: absolute;
  left: 50%;
  top: 50%;
  transform: translate(-50%, -50%);
  width: 20vw;
  height: 20vw;
  border: 1px dashed gray;
  text-align: center;
  line-height: 20vw;
  font-size: 15px;
  color: gray;
  display: block;
  z-index: 10;
}
.select-box {
  height: 100px;
  margin: 20px 30px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  color: #fff;
  font-size: 36px;
  .sure-bt {
    width: 200px;
    height: 80px;
    line-height: 80px;
    border-radius: 10px;
    background: #44bb00;
  }
  .cancel-bt {
    width: 200px;
    height: 80px;
    line-height: 80px;
    border-radius: 10px;
    background: #ff976a;
  }
}
</style>

blob代码如下

export const dataURItoBlob = function (base64Data) {
    var byteString;
    if (base64Data.split(',')[0].indexOf('base64') >= 0)
        byteString = atob(base64Data.split(',')[1]);
    else
        // byteString = unescape(base64Data.split(',')[1]);
        byteString = decodeURI(base64Data.split(',')[1]);
    var mimeString = base64Data.split(',')[0].split(':')[1].split(';')[0];
    var ia = new Uint8Array(byteString.length);
    for (var i = 0; i < byteString.length; i++) {
        ia[i] = byteString.charCodeAt(i);
    }
    return new Blob([ia], {type: mimeString});
}

这样就可以实现拍照上传：
注意：
在验证数据是否append到fordata中，用formData.get(‘action’),部分ios不兼容这个方法要注释掉
如果是放在自己app种webView中安卓app需要对其做支持否则input可能无法触发，H5浏览器则完全适用