var filechooser = document.getElementById("choose");//    用于压缩图片的canvasvar canvas = document.createElement("canvas");var ctx = canvas.getContext('2d');//    瓦片canvasvar tCanvas = document.createElement("canvas");var tctx = tCanvas.getContext("2d");var maxsize = 100 * 1024;var Orientation = null; $("#upload").on("click", function() {filechooser.click();}).on("touchstart", function() {$(this).addClass("touch")}).on("touchend", function() {$(this).removeClass("touch")});filechooser.onchange = function() {if (!this.files.length) return;var files = Array.prototype.slice.call(this.files);if (files.length > 9) {alert("最多同时只可上传9张图片");return;}files.forEach(function(file, i) {if (!/\/(?:jpeg|png|gif)/i.test(file.type)) return;EXIF.getData(file, function() {  EXIF.getAllTags(this);   Orientation = EXIF.getTag(this, 'Orientation');  }); var reader = new FileReader();var li = document.createElement("li");
//          获取图片大小var size = file.size / 1024 > 1024 ? (~~(10 * file.size / 1024 / 1024)) / 10 + "MB" : ~~(file.size / 1024) + "KB";li.innerHTML = '<div class="progress"><span></span></div><a href="javascript:void(0);" title="" data-index="'+i+'" οnclick="delpic('+i+')"  ></a>';$(".img-list").append($(li));reader.onload = function() {var result = this.result;var img = new Image();img.src = result;/**if (navigator.userAgent.match(/iphone/i)) {            if(Orientation != "" && Orientation != 1){  //alert('旋转处理');                  switch(Orientation){  case 6://需要顺时针（向左）90度旋转  //alert('需要顺左');img.src = rotateImg(img,'left',canvas);  console.log(img.src);break;  case 8://需要逆时针（向右）90度旋转                       console.log('需要向右');img.src = rotateImg(img,'right',canvas);  break;  case 3://需要180度旋转  console.log('需要180度');                      img.src = rotateImg(img,'right',canvas);//转两次  img.src = rotateImg(img,'right',canvas);  break;  }         }  }**/$(li).css("background-image", "url(" + img.src + ")");//$(li).css("background-image", "url(" + result + ")");$(li).css("background-size", "100% 100%");$(li).attr('id','uploadImg_'+i);//如果图片大小小于100kb，则直接上传if (result.length <= maxsize) {//img = null;result = img.src;upload(result, file.type, $(li),i);return;}
//      图片加载完毕之后进行压缩，然后上传if (img.complete) {callback();} else {img.onload = callback;}function callback() {var data = compress(img);upload(data, file.type, $(li),i);img = null;}};reader.readAsDataURL(file);})};function rotateImg(img, direction,canvas) {    //alert(img);  //最小与最大旋转方向，图片旋转4次后回到原方向    var min_step = 0;    var max_step = 3;    //var img = document.getElementById(pid);    if (img == null)return;    //img的高度和宽度不能在img元素隐藏后获取，否则会出错    var height = img.height;    var width = img.width;    //var step = img.getAttribute('step');    var step = 2;    if (step == null) {    step = min_step;    }    if (direction == 'right') {    step++;    //旋转到原位置，即超过最大值    step > max_step && (step = min_step);    } else {    step--;    step < min_step && (step = max_step);    }    //旋转角度以弧度值为参数    var degree = step * 90 * Math.PI / 180;    var ctx = canvas.getContext('2d');    switch (step) {    case 0:    canvas.width = width;    canvas.height = height;    ctx.drawImage(img, 0, 0);    break;    case 1:    canvas.width = height;    canvas.height = width;    ctx.rotate(degree);    ctx.drawImage(img, 0, -height);    break;    case 2:    canvas.width = width;    canvas.height = height;    ctx.rotate(degree);    ctx.drawImage(img, -width, -height);    break;    case 3:    canvas.width = height;    canvas.height = width;    ctx.rotate(degree);    ctx.drawImage(img, -width, 0);    break;    }var ndata = canvas.toDataURL('image/jpeg');return ndata;}//删除//    使用canvas对大图片进行压缩function delpic(i){$("#content"+i).remove();$("#uploadImg_"+i).remove();
}function compress(img) {var initSize = img.src.length;var width = img.width;var 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var 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var 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var nw = ~~(width / count);var nh = ~~(height / count);tCanvas.width = nw;tCanvas.height = nh;for (var i = 0; i < count; i++) {for (var 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);}//进行最小压缩var ndata = canvas.toDataURL('image/jpeg', 0.1);//console.log('压缩前：' + initSize);//console.log('压缩后：' + ndata.length);//console.log('压缩率：' + ~~(100 * (initSize - ndata.length) / initSize) + "%");tCanvas.width = tCanvas.height = canvas.width = canvas.height = 0;return ndata;}//    图片上传，将base64的图片转成二进制对象，塞进formdata上传function upload(basestr, type, $li,index) {var text = window.atob(basestr.split(",")[1]);var buffer = new Uint8Array(text.length);var pecent = 0, loop = null;for (var i = 0; i < text.length; i++) {buffer[i] = text.charCodeAt(i);}var blob = getBlob([buffer], type);var xhr = new XMLHttpRequest();var formdata = getFormData();formdata.append('imagefile', blob);xhr.open('post', './ajax_image');xhr.onreadystatechange = function() {if (xhr.readyState == 4 && xhr.status == 200) {//var jsonData = $.parsejson(xhr.responseText);var obj = eval("("+xhr.responseText+")");   console.log(obj.path);if(obj.iResult==1){var html = '<input type="hidden" value="'+obj.path+'" name="content[]" id="content'+index+'" >';$("#photofile").append(html);}else{alert('上传失败');}var text = obj.iResult==1 ? '上传成功' : '上传失败';//console.log(text + '：' + obj.path);clearInterval(loop);//当收到该消息时上传完毕$li.find(".progress ").animate({'width': "100%"}, pecent < 95 ? 200 : 0, function() {$(this).html(text);});if (!obj.path) return;//$(".pic-list").append('<a href="' + imagedata.path + '">' + imagedata.name + '（' + imagedata.size + '）<img src="' + imagedata.path + '" /></a>');}};//数据发送进度，前50%展示该进度xhr.upload.addEventListener('progress', function(e) {if (loop) return;pecent = ~~(100 * e.loaded / e.total) / 2;$li.find(".progress ").css('width', pecent + "%");if (pecent == 50) {mockProgress();}}, false);//数据后50%用模拟进度function mockProgress() {if (loop) return;loop = setInterval(function() {pecent++;$li.find(".progress").css('width', pecent + "%");if (pecent == 99) {clearInterval(loop);}}, 100)}xhr.send(formdata);}/*** 获取blob对象的兼容性写法* @param buffer* @param format* @returns {*}*/function getBlob(buffer, format) {try {return new Blob(buffer, {type: format});} catch (e) {var bb = new (window.BlobBuilder || window.WebKitBlobBuilder || window.MSBlobBuilder);buffer.forEach(function(buf) {bb.append(buf);});return bb.getBlob(format);}}/*** 获取formdata*/function getFormData() {var isNeedShim = ~navigator.userAgent.indexOf('Android')&& ~navigator.vendor.indexOf('Google')&& !~navigator.userAgent.indexOf('Chrome')&& navigator.userAgent.match(/AppleWebKit\/(\d+)/).pop() <= 534;return isNeedShim ? new FormDataShim() : new FormData()}/*** formdata 补丁, 给不支持formdata上传blob的android机打补丁* @constructor*/function FormDataShim() {console.warn('using formdata shim');var o = this,parts = [],boundary = Array(21).join('-') + (+new Date() * (1e16 * Math.random())).toString(36),oldSend = XMLHttpRequest.prototype.send;this.append = function(name, value, filename) {parts.push('--' + boundary + '\r\nContent-Disposition: form-data; name="' + name + '"');if (value instanceof Blob) {parts.push('; filename="' + (filename || 'blob') + '"\r\nContent-Type: ' + value.type + '\r\n\r\n');parts.push(value);}else {parts.push('\r\n\r\n' + value);}parts.push('\r\n');};// Override XHR send()XMLHttpRequest.prototype.send = function(val) {var fr,data,oXHR = this;if (val === o) {// Append the final boundary stringparts.push('--' + boundary + '--\r\n');// Create the blobdata = getBlob(parts);// Set up and read the blob into an array to be sentfr = new FileReader();fr.onload = function() {oldSend.call(oXHR, fr.result);};fr.onerror = function(err) {throw err;};fr.readAsArrayBuffer(data);// Set the multipart content type and boudarythis.setRequestHeader('Content-Type', 'multipart/form-data; boundary=' + boundary);XMLHttpRequest.prototype.send = oldSend;}else {oldSend.call(this, val);}};}