html
<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>js上传图片</title>
<script src="Script/plugins/0com/exif.js"></script>
</head>
<body>
<input id="file" type="file">
<script type="text/javascript">
var fileTypes = [‘image/jpeg‘, ‘image/gif‘, ‘image/png‘];
window.onload = function myfunction() {
var input = document.getElementById(‘file‘);
input.onchange = function () {
var files = this.files;
for (var i = 0, len = files.length; i < len; i++) {
var file = files[i];
if (!fileTypes.includes(file.type)) {
alert("只可上传图片")
return false;
}
if (file.size / 1024 > 1025) {
photoCompress(file, { quality: 0.3 }, upload_html5);
}
else {
upload_html5(file);
}
}
};
}
function upload_html5(file) {
var xhr = new XMLHttpRequest();
xhr.upload.addEventListener("progress", function (e) { }, false);
xhr.addEventListener("load", function (e) {
var obj = JSON.parse(e.target.responseText);
if (obj.code == 200) {
alert("上传成功");
}
else {
alert(obj.message);
}
}, false);
xhr.addEventListener("error", function (e) {
console.log(e);
alert("上传失败");
}, false);
xhr.addEventListener("abort", function (e) {
alert("上传取消");
}, false);
var fd = new FormData;
fd.append("file", file);
fd.append("hallName", ‘分会场1‘);
fd.append("dateTime", ‘2019-06-21‘);
xhr.open("post", "/Common/UploadFile");
xhr.send(fd);
}
/*
三个参数
file：一个是文件(类型是图片格式)，
w：一个是文件压缩的后宽度，宽度越小，字节越小
objDiv：一个是容器或者回调函数
photoCompress()
*/
function photoCompress(file, obj, objDiv) {
var Orientation = null;//ios选择上传图片是图片角度问题
EXIF.getData(file, function () {
EXIF.getAllTags(this);
Orientation = EXIF.getTag(this, ‘Orientation‘);
});
var ready = new FileReader();
/*开始读取指定的Blob对象或File对象中的内容. 当读取操作完成时,readyState属性的值会成为DONE,
* 如果设置了onloadend事件处理程序,则调用之.同时,result属性中将包含一个data: URL格式的字符串以表示所读取文件的内容.*/
ready.readAsDataURL(file);
ready.onload = function () {
canvasDataURL(this.result, obj, Orientation, objDiv)
}
}
function canvasDataURL(path, obj, Orientation, callback) {
var img = new Image();
img.src = path;
img.onload = function () {
var that = this;
// 默认按比例压缩
var w = that.width,
h = that.height,
scale = w / h;
w = obj.width || w;
h = obj.height || (w / scale);
var quality = 0.7; // 默认图片质量为0.7
//生成canvas
var canvas = document.createElement(‘canvas‘);
var ctx = canvas.getContext(‘2d‘);
// 创建属性节点
var anw = document.createAttribute("width");
anw.nodeValue = w;
var anh = document.createAttribute("height");
anh.nodeValue = h;
canvas.setAttributeNode(anw);
canvas.setAttributeNode(anh);
if (Orientation != "" && Orientation != 1 && Orientation != undefined) {
switch (Orientation) {
case 6://需要顺时针90度旋转
canvas.width = h;
canvas.height = w;
ctx.rotate(90 * Math.PI / 180);
ctx.drawImage(this, 0, -h);
break;
case 8://需要逆时针90度旋转
canvas.width = h;
canvas.height = w;
ctx.rotate(-90 * Math.PI / 180);
ctx.drawImage(this, -w, 0);
break;
case 3://需要180度旋转
ctx.rotate(180 * Math.PI / 180);
ctx.drawImage(this, -w, -h);
break;
}
}
else {
ctx.drawImage(that, 0, 0, w, h);
}
// 图像质量
if (obj.quality && obj.quality <= 1 && obj.quality > 0) {
quality = obj.quality;
}
// quality值越小，所绘制出的图像越模糊
var base64 = canvas.toDataURL(‘image/jpeg‘, quality);
// 回调函数返回base64的值
callback(base64);
}
}
/**
* 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
*/
function convertBase64UrlToBlob(urlData) {
var arr = urlData.split(‘,‘), mime = arr[0].match(/:(.*?);/)[1],
bstr = atob(arr[1]), n = bstr.length, u8arr = new Uint8Array(n);
while (n--) {
u8arr[n] = bstr.charCodeAt(n);
}
return new Blob([u8arr], { type: mime });
}
</script>
</body>
</html>
原文地址：https://www.cnblogs.com/kikyoqiang/p/11074975.html
时间： 2024-11-05 14:21:47