vue 移动端上传图片

1,图片组件

<p class="titleImgWrap">{{Imgtitle}}</p>

</div>

</template>

import EXIF from "@/utils/small-exif"

export default {

props: {

photoEventNumber: Number,

Imgtitle:String

data() {

return {

headerImage: "",

picValue: ""

};

mounted() {},

watch: {

photoEventNumber: {

handler() {

var userAgent = navigator.userAgent;

var el = this.$refs.file;

}

methods: {

upload(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 = new FileReader();

// 将图片2将转成 base64 格式

reader.readAsDataURL(file);

// 读取成功后的回调

reader.onloadend = function() {

let result = this.result;

let img = new Image();

img.src = result;

//判断图片是否大于100K,是就直接上传，反之压缩图片

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();

};

}

};

}

postImg() {

//这里写接口

var photoFile = this.convertBase64UrlToBlob(this.headerImage);

var photo = {};

photo.base64 = this.headerImage;

photo.file = photoFile;

this.$emit("photoData", photo);

/* 将以base64的图片url数据转换为Blob

* @param urlData

* 用url方式表示的base64图片数据

convertBase64UrlToBlob(urlData) {

var bytes = window.atob(urlData.split(",")[1]); //去掉url的头，并转换为byte

//处理异常,将ascii码小于0的转换为大于0

var ab = new ArrayBuffer(bytes.length);

var ia = new Uint8Array(ab);

for (var i = 0; i < bytes.length; i++) {

ia[i] = bytes.charCodeAt(i);

}

return new Blob([ab], {

type: "image/png"

});

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;

}

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) {

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) {

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,

nw,

);

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;

return ndata;

}

};

</script>

* {

margin: 0;

padding: 0;

}

.imgWrap {

display: flex;

align-items: center;

padding: 20px 0;

}

p.titleImgWrap {

font-size: 0.37333rem;

color: #333a44;

padding: 0.26667rem 0.4rem;

}

.imgBtn {

position: relative;

width: 60px;

height: 60px;

background: rgba(242, 246, 252, 1);

text-align: center;

line-height: 60px;

}

.show {

width: 200px;

height: 200px;

overflow: hidden;

position: relative;

border: 1px solid #d5d5d5;

}

.picture {

width: 100%;

height: 100%;

overflow: hidden;

background-position: center center;

background-repeat: no-repeat;

background-size: cover;

}

input {

position: absolute;

left: 0;

top: 0;

width: 100%;

height: 100%;

opacity: 0;

}

</style>

2，使用父组件

html:

</div>

</p>

</div>

<van-image-preview v-model="show" :images="imgList" showIndex :startPosition="startPosition"></van-image-preview>

</van-cell-group>

js:

data(){

return{

imgBase64: [],

Imgtitle: "销售合同",

imgList: [],

photo: "",

BASE_IMG_URL: BASE_URL_IMG,

startPosition: 0,

applicationStepsNeedData: {

type: 3

applicationId: "",

photoEventNumber: 1,

}}

methods:{

//上传图片

uploadPhoto() {

this.photoEventNumber = ++this.photoEventNumber;

getData(datas) {

this.photo = datas.file;

this.$toast("上传中...");

uploadImg(this.photo)

.then(res => {

if (res.code == 200) {

this.imgBase64.push(res.msg);

}

})

.catch(err => {

this.$toast("上传失败，请重试");

console.log(err);

});

//预览图片

preview(i) {

this.startPosition = i;

this.show = true;

this.imgList = [];

this.imgBase64.map(item => {

this.imgList.push(this.BASE_IMG_URL + item);

});

// console.log(this.imgList);

//删除图片

delImg(index) {

this.imgBase64.splice(index, 1);

}

exft.js

var EXIF = {};

var TiffTags = EXIF.TiffTags = {

0x0112: "Orientation"

};

function imageHasData(img) {

return !!(img.exifdata);

}

function getImageData(img, callback) {

function handleBinaryFile(binFile) {

var data = findEXIFinJPEG(binFile);

img.exifdata = data || {};

if (callback) {

callback.call(img);

}

if (window.FileReader && (img instanceof window.Blob || img instanceof window.File)) {

var fileReader = new FileReader();

fileReader.onload = function (e) {

handleBinaryFile(e.target.result);

};

fileReader.readAsArrayBuffer(img);

}

function findEXIFinJPEG(file) {

var dataView = new DataView(file);

if ((dataView.getUint8(0) != 0xFF) || (dataView.getUint8(1) != 0xD8)) {

return false; // not a valid jpeg

}

var offset = 2,

length = file.byteLength,

marker;

while (offset < length) {

if (dataView.getUint8(offset) != 0xFF) {

return false; // not a valid marker, something is wrong

}

marker = dataView.getUint8(offset + 1);

if (marker == 225) {

return readEXIFData(dataView, offset + 4, dataView.getUint16(offset + 2) - 2);

} else {

offset += 2 + dataView.getUint16(offset + 2);

}

function readTags(file, tiffStart, dirStart, strings, bigEnd) {

var entries = file.getUint16(dirStart, !bigEnd),

tags = {},

entryOffset, tag,

for (i = 0; i < entries; i++) {

entryOffset = dirStart + i * 12 + 2;

tag = strings[file.getUint16(entryOffset, !bigEnd)];

tags[tag] = readTagValue(file, entryOffset, tiffStart, dirStart, bigEnd);

}

return tags;

}

function readTagValue(file, entryOffset, tiffStart, dirStart, bigEnd) {

var type = file.getUint16(entryOffset + 2, !bigEnd),

numValues = file.getUint32(entryOffset + 4, !bigEnd),

valueOffset = file.getUint32(entryOffset + 8, !bigEnd) + tiffStart,

offset,

vals, val, n,

numerator, denominator;

switch (type) {

case 1: // byte, 8-bit unsigned int

case 7: // undefined, 8-bit byte, value depending on field

if (numValues == 1) {

return file.getUint8(entryOffset + 8, !bigEnd);

} else {

offset = numValues > 4 ? valueOffset : (entryOffset + 8);

vals = [];

for (n = 0; n < numValues; n++) {

vals[n] = file.getUint8(offset + n);

}

return vals;

}

case 2: // ascii, 8-bit byte

offset = numValues > 4 ? valueOffset : (entryOffset + 8);

return getStringFromDB(file, offset, numValues - 1);

case 3: // short, 16 bit int

if (numValues == 1) {

return file.getUint16(entryOffset + 8, !bigEnd);

} else {

offset = numValues > 2 ? valueOffset : (entryOffset + 8);

vals = [];

for (n = 0; n < numValues; n++) {

vals[n] = file.getUint16(offset + 2 * n, !bigEnd);

}

return vals;

}

case 4: // long, 32 bit int

if (numValues == 1) {

return file.getUint32(entryOffset + 8, !bigEnd);

} else {

vals = [];

for (n = 0; n < numValues; n++) {

vals[n] = file.getUint32(valueOffset + 4 * n, !bigEnd);

}

return vals;

}

case 5: // rational = two long values, first is numerator, second is denominator

if (numValues == 1) {

numerator = file.getUint32(valueOffset, !bigEnd);

denominator = file.getUint32(valueOffset + 4, !bigEnd);

val = new Number(numerator / denominator);

val.numerator = numerator;

val.denominator = denominator;

return val;

} else {

vals = [];

for (n = 0; n < numValues; n++) {

numerator = file.getUint32(valueOffset + 8 * n, !bigEnd);

denominator = file.getUint32(valueOffset + 4 + 8 * n, !bigEnd);

vals[n] = new Number(numerator / denominator);

vals[n].numerator = numerator;

vals[n].denominator = denominator;

}

return vals;

}

case 9: // slong, 32 bit signed int

if (numValues == 1) {

return file.getInt32(entryOffset + 8, !bigEnd);

} else {

vals = [];

for (n = 0; n < numValues; n++) {

vals[n] = file.getInt32(valueOffset + 4 * n, !bigEnd);

}

return vals;

}

case 10: // signed rational, two slongs, first is numerator, second is denominator

if (numValues == 1) {

return file.getInt32(valueOffset, !bigEnd) / file.getInt32(valueOffset + 4, !bigEnd);

} else {

vals = [];

for (n = 0; n < numValues; n++) {

vals[n] = file.getInt32(valueOffset + 8 * n, !bigEnd) / file.getInt32(valueOffset + 4 + 8 * n, !bigEnd);

}

return vals;

}

function getStringFromDB(buffer, start, length) {

var outstr = "";

for (var n = start; n < start + length; n++) {

outstr += String.fromCharCode(buffer.getUint8(n));

}

return outstr;

}

function readEXIFData(file, start) {

if (getStringFromDB(file, start, 4) != "Exif") {

return false;

}

var bigEnd,

tags, tag,

exifData, gpsData,

tiffOffset = start + 6;

// test for TIFF validity and endianness

if (file.getUint16(tiffOffset) == 0x4949) {

bigEnd = false;

} else if (file.getUint16(tiffOffset) == 0x4D4D) {

bigEnd = true;

} else {

return false;

}

if (file.getUint16(tiffOffset + 2, !bigEnd) != 0x002A) {

return false;

}

var firstIFDOffset = file.getUint32(tiffOffset + 4, !bigEnd);

if (firstIFDOffset < 0x00000008) {

return false;

}

tags = readTags(file, tiffOffset, tiffOffset + firstIFDOffset, TiffTags, bigEnd);

return tags;

}

EXIF.getData = function (img, callback) {

if ((img instanceof Image || img instanceof HTMLImageElement) && !img.complete) return false;

if (!imageHasData(img)) {

getImageData(img, callback);

} else {

if (callback) {

callback.call(img);

}

return true;

}

EXIF.getTag = function (img, tag) {

if (!imageHasData(img)) return;

return img.exifdata[tag];

}

export default EXIF

// 页面引入方式 import EXIF from "@/utils/small-exif"