data() {return{

files: {

name:"",

type:""},

headerImage:null,

picValue:null,

upImgUrl,

}

},//组件方法 获取 流

asynconRead(file) {//console.log(file);//console.log(file.file);

this.files.name = file.file.name; //获取文件名

this.files.type = file.file.type; //获取类型

this.picValue = file.file; //文件流

this.imgPreview(this.picValue);

},//处理图片

imgPreview(file) {

let self= this;

let Orientation;//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;if (/^image/.test(file.type)) {//创建一个reader

let reader = newFileReader();//将图片2将转成 base64 格式

reader.readAsDataURL(file);//读取成功后的回调

reader.onloadend =function () {//console.log(this.result);

let result = this.result;

let img= newImage();

img.src=result;//判断图片是否大于500K,是就直接上传，反之压缩图片

if (this.result.length <= 500 * 1024) {

self.headerImage= this.result;

self.postImg();

}else{

img.οnlοad=function () {

let data=self.compress(img, Orientation);

self.headerImage=data;

self.postImg();

};

}

};

}

},//压缩图片

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 < 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);

tCanvas.width= tCanvas.height = canvas.width = canvas.height = 0;returnndata;

},//旋转图片

rotateImg(img, direction, canvas) {//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;

}

},//将base64转换为文件

dataURLtoFile(dataurl) {var arr = dataurl.split(","),

bstr= atob(arr[1]),

n=bstr.length,

u8arr= newUint8Array(n);while (n--) {

u8arr[n]=bstr.charCodeAt(n);

}return new File([u8arr], this.files.name, {

type:this.files.type

});

},//这里写接口

asyncpostImg() {

let file= this.dataURLtoFile(this.headerImage);

let formData= newwindow.FormData();

formData.append("file", file);

toast_loding(this, "图片上传中···");try{

let res= await util.ajax.post(this.upImgUrl, formData, {

headers: {"Content-Type": "multipart/form-data"}

});

}catch(e) {

console.log(e);

}

}