vue2.X+HTML5plus拍照和调用设备相册另附图片转base64和压缩图片方法

tesCamera(){
    let that = this;
    //调用原生系统弹出按钮选择框
    let page = null;
    page={ 
        imgUp:function(){ 
            plus.nativeUI.actionSheet(
                {cancel:"取消",buttons:[ 
                {title:"拍照"}, 
                {title:"从相册中选择"} 
            ]}, function(e){
                //1 是拍照  2 从相册中选择 
                switch(e.index){ 
                    case 1:
                    getImage();
                    break; 
                    case 2:
                    appendByGallery();
                    break; 
                    default:
                    break;    
                } 
            }); 
        } 
    }
    // 拍照函数
    function getImage(){
        let cmr = plus.camera.getCamera();
        cmr.captureImage(function(p){
            plus.io.resolveLocalFileSystemURL(p, function(entry){
                var path = entry.toLocalURL();
                //文件传转base64方法
                that.imgPreviewnew(path, _typedata);
            }, function(e){
                console.log("读取拍照文件错误："+e.message);
            });
        }, function(e){
            console.log("读取拍照文件错误："+e.message);
        }, {filename:'_doc/camera/',index:1});
    }

    //选择相片文件
    function appendByGallery(){
        plus.gallery.pick(function(path){
            //文件传转base64方法
            that.imgPreviewnew(path, _typedata);
        });
    }
    // 弹出系统选择按钮框  
    page.imgUp();
}

imgPreviewnew(file, type){
    let that = this;
    let Orientation;
    let img = new Image();
    img.src = file;
    img.onload = function () {
        //压缩图片函数-输出base64
        let data = that.compress(img,Orientation);
    }
}

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;
  //如果图片大于四百万像素，计算压缩比并将大小压至400万以下
  let ratio;
  if ((ratio = width * height / 4000000) > 1) {
    console.log("大于400万像素")
    ratio = Math.sqrt(ratio);
    width /= ratio;
    height /= ratio;
  } else {
    ratio = 1;
  }
  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 ) {
      for (let j = 0; 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(img,'left',canvas);
          break;
      case 8://需要逆时针（向右）90度旋转
          this.rotateImg(img,'right',canvas);
          break;
      case 3://需要180度旋转
          this.rotateImg(img,'right',canvas);//转两次
          this.rotateImg(img,'right',canvas);
          break;
    }
  }
  //进行最小压缩
  let ndata = canvas.toDataURL('image/jpeg', 0.1);
  console.log('压缩前：' + initSize);
  console.log('压缩后：' + ndata.length);
  console.log('压缩率：' + ~~(100 * (initSize - ndata.length) / initSize) + "%");
  tCanvas.width = tCanvas.height = canvas.width = canvas.height = 0;
  return ndata;
}