前几个月闲得无聊写得一段代码，没想最近刚好用上了，在硬盘里翻了半天找回来，还没好好整理直接用上了
图片会处理成PNG，比jpg 大很多，最好判断一下用户上传的图片size 大到一定程度再决定是否使用该方法
最长边800*600像素的PNG一般在1M左右
大的 jpg 转换成尺寸小一点的图片可以一用，比如用户拍照上传的图片一般都在1M 到4M 之间，如果只是用作头像尺寸就可以缩小很多，1M甚至几M的图转换成几百K。
<!doctype html> <html> <head> <title>test</title> <script src="js/zepto-master/src/zepto.min.js"></script> <script>
/*****
by cnblogs.com/ecalf
**/
var uploadImg = (function($){
function fileUpLoader(config){
if(typeof(config.field)==‘string‘){//input type=file
config.field = document.getElementById(config.field);
}
if(typeof(config.viewPane)==‘string‘){//预览图
config.viewPane = document.getElementById(config.viewPane);
}
if(typeof(config.uploadBtn)==‘string‘){//上传按钮
config.uploadBtn = document.getElementById(config.uploadBtn);
}
this.afterSelectFile = config.afterSelectFile||function(){};
this.maxSize = config.maxSize==undefined?4194304:(config.maxSize||0);//maxSize 0 不限制大小
this.field = config.field;
this.viewPane = config.viewPane;
this.uploadBtn = config.uploadBtn;
if(config.uploadUrl){
this.uploadUrl = config.uploadUrl;
}
if(typeof(config.afterUpload)==‘function‘){
this.afterUpload = config.afterUpload;
}
if(Object(config.extParams)===config.extParams){
this.extParams = config.extParams;
}
this.init();
}
fileUpLoader.prototype = {
init:function(){
this.domEvents();
console.log(‘uploadfile init‘);
},
domEvents:function(){
var host = this;
if(host.field&&host.afterSelectFile){
$(host.field).on("change",function(e){
host.afterSelectFile&&host.afterSelectFile(this);
});
}
if(host.uploadBtn){
$(host.uploadBtn).on(‘click‘,function(){
host.upload();
});
}
},
imgToDataURL:function(img,callback,frag){
var databack={
status:true,
dataURL:‘‘,
callback:callback,
resolve:function(){
this.callback(this.dataURL);
}
}
var trans = function(pic){//canvas.toDataURL,context.getImageData 不能读取跨域图片
pic.crossOrigin = "*";
var cvs = document.createElement("canvas");
document.body.appendChild(cvs);
var ctx = cvs.getContext(‘2d‘);
cvs.width = pic.width;
cvs.height = pic.height;
console.log(‘img size:‘,pic.width+‘px‘,pic.height+‘px‘);
ctx.drawImage(pic,0,0,pic.width,pic.height);
var dataURL = cvs.toDataURL();
console.log(‘dataURL length:‘,dataURL.length)
cvs = null;
ctx = null;
return dataURL;
};
if(!frag&&img.width&&img.height){ //img 加载完才能取出img的数据，如果在domReady 里面执行，图片未加载完会绘制出空白的 canvas
console.log(‘trans directly‘);
databack.dataURL = trans(img);
databack.resolve();
}else{//使用 图片的 natural size，img loaded后才能获得高宽
databack.status = false;
var pic = new Image();
pic.crossOrigin = "*";
pic.onload = function(e){
console.log(‘trans onload‘);
databack.dataURL = trans(e.target);
databack.status = true;
databack.resolve();
pic = null;
};
pic.src = img.src;
}
return databack;
},
dataURLToBlob:function(dataURL){
console.log(dataURL.length)
var type = dataURL.match(/data:(.+?);/);
type = type?type[1]:‘image/png‘;
var dataContent = dataURL.replace(/^.+,/,‘‘);
dataContent = atob(dataContent);
var dataCharCode = [];
var i = 0;
while(i<dataContent.length){
dataCharCode[i] = dataContent.charCodeAt(i);
i++;
}
var u8Arr = new Uint8Array(dataCharCode);
return new Blob([u8Arr],{type:type}); // you maybe use new BolbBuilder() in older browser
},
readURL:function (input,callback) {//创建预览图
input = input||this.field;
if (input.files && input.files[0]) {
if(this.maxSize&&input.files[0].size > this.maxSize){
alert(‘文件大于‘+(this.maxSize/(1024*1024))+‘m，请重新上传‘);
return false;
}
var reader = new FileReader();
reader.onload = function (e) {
callback&&callback(e.target.result);
};
var dataUrl = reader.readAsDataURL(input.files[0]);
reader = null;
return dataUrl;
}
},
upload:function(fileConfig){
var host = this;
var formData = new FormData();
var file,name,filename;
if(!fileConfig){
name = host.field.name;
file = host.field.files[0];
filename = host.field.value.split(/[/\\]/).pop()||"temp.png";
}else{
name = fileConfig.name;
file = fileConfig.file;
filename = fileConfig.filename||"temp.png";
}
if(!file){
console.log(‘no file‘);
}
formData.append(name,file,filename);
if(Object(host.extParams)===host.extParams){
$.each(host.extParams,function(k,v){
formData.append(k,v);
});
}
$.ajax({
url: host.uploadUrl,
type: ‘POST‘,
data: formData,
async: true,
dataType:‘json‘,
cache: false,
contentType: false,
processData: false,
timeout:45000,
success: function (data,status, xhr) {
host.afterUpload&&host.afterUpload(data);
},
error:function(xhr, errorType, error){
console.log(errorType, error);
},
complete:function(xhr, status){
console.log(‘post complete,status:‘,status);
}
});
}//end upload
};
return {
init:function(config){
return new fileUpLoader(config);
}
};
})(Zepto);
$(document).ready(function(){
upload = uploadImg.init({
field:‘uploadimg‘,
viewPane:‘viewPane‘,
uploadBtn:‘submitbtn‘,
uploadUrl:‘yourimguploadurl.jsp‘,
maxSize:0,
afterUpload:function(resp){ },
extParams:{uid:12}
});
window.onload = function(){
var img = document.querySelector("img");
upload.imgToDataURL(img,function(DataURL){
var blob = upload.dataURLToBlob(DataURL);
console.log(blob);
},true);
};
$("#uploadimg").on("change",function(){
var file = this.files[0];
if(!file){ return; }
upload.readURL(this,function(dataURL){
upload.viewPane&&(upload.viewPane.src = dataURL);
var img = new Image();
img.onload = function(){
var img = document.querySelector("img");
upload.imgToDataURL(img,function(dataURL){
var blob = upload.dataURLToBlob(dataURL);
console.log(blob);
},false);
}
img.src=dataURL;
});
});
});
</script>
</head>
<body>
<div>
<img id="viewPane" width="800" height="600" src="img/1111.png" />
<form id="testform">
<!-- camera--照相机；camcorder--摄像机；microphone--录音 -->
<input id="uploadimg" type="file" accept="image/*" capture="camera" />
<input id="submitbtn" type="submit" />
</form>
</div>
</body>
</html>
时间： 2024-10-06 18:07:41