1,图片组件
<template>
<div class="imgWrap">
<p class="titleImgWrap">{{Imgtitle}}</p>
<div class="imgBtn">
<span>+</span>
<input style ref="file" type="file" id="upload" accept="image/*" @change="upload">
</div>
</div>
</template>
<script>
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,
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;
return ndata;
}
}
};
</script>
<style scoped>
* {
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 @click="uploadPhoto">
<uploaderImg :photoEventNumber="photoEventNumber" @photoData="getData" :Imgtitle="Imgtitle"></uploaderImg>
</div>
<div class="showImgs" v-if="imgBase64 && imgBase64.length > 0">
<p v-for="(item,index) in imgBase64" :key="index">
<img :src="BASE_IMG_URL+item" @click="preview(index)">
<span @click="delImg(index)">删除</span>
</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,
i;
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"
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