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jquery.imagecompress.js
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jquery.imagecompress.js
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+function ($) {
'use strict';
var successCount = 0;
/**
* 闭包中的构造方法
* @param evt 上传文件域的change事件对象
* @param options 用户定义参数(图片压缩质量,处理完成回调函数,图片输出格式)
*/
var ImageCompress = function (evt, options) {
var that = this;
//读取图片
var originalImage = this.readFile(evt, options.onloadStart, function(){
if(typeof options.onloadEnd === 'function'){
options.onloadEnd(this);
}
if(typeof options.oncompressStart === 'function'){
options.oncompressStart(this);
}
//读取完成,压缩图片
var compressImage = that.compress(this, options.quality, options.outputFormat);
if(typeof options.oncompressEnd === 'function'){
options.oncompressEnd(compressImage);
}
successCount++;
if(typeof options.callback === 'function' && successCount == length){
options.callback(compressImage);
successCount = 0;
}
return compressImage;
});
}
// 原型方法
/**
* 压缩图片
* @param imageObj 图片对象
* @param quality 压缩质量
* @param outputFormat 图片输出格式
* return returnImageObj 返回压缩后的图片对象
*/
ImageCompress.prototype.compress = function(imageObj, quality, outputFormat){
var mimeType = "image/jpeg";
if(outputFormat!=undefined && outputFormat=="png"){
mimeType = "image/png";
}
var cvs = document.createElement('canvas');
//naturalWidth真实图片的宽度
cvs.width = imageObj.naturalWidth;
cvs.height = imageObj.naturalHeight;
var ctx = cvs.getContext("2d").drawImage(imageObj, 0, 0);
var newImageData = cvs.toDataURL(mimeType, quality/100);
var returnImageObj = new Image();
returnImageObj.src = newImageData;
return returnImageObj;
}
/**
* 读取图片
* @param evt 上传文件域的change事件对象
* @param onloadCallback 当文件读取完毕后的回调
*/
ImageCompress.prototype.readFile = function(evt, onloadStart, onloadCallback) {
var files = evt.target.files;
var length = files.length;
for (var i = 0, file; file = files[i]; i++) {
// 只处理图片
if (!file.type.match('image.*')) {
continue;
}
if(typeof onloadStart === 'function'){
onloadStart(file);
}
var reader = new FileReader();
// Closure to capture the file information.
reader.onload = (function(theFile, index) {
return function(e) {
// Render thumbnail.
var img = new Image();
//用户回调函数
img.onload = onloadCallback
img.src = e.target.result;
};
})(file);
// Read in the image file as a data URL.
reader.readAsDataURL(file);
}
}
//默认参数
ImageCompress.DEFAULTS = {
}
//在jQuery对象上提供的静态方法
$.extend({
});
//如果有原型方法
$.fn.extend({
imageCompress: function(options) {
var $this = $(this);
$this.on('change', function(evt){
var model = new ImageCompress(evt, options);
});
}
});
//noconflict
$.fn.imageCompress.noConflict = function () {
}
//代理的事件监听
}(jQuery);