HTML5前端图片压缩，兼容手机

来源：互联网发布：网络维护人员工作理念编辑：程序博客网时间：2024/04/29 22:08

主要用了两个html5的 API，一个file，一个canvas，压缩主要使用cnavas做的，file是读取文件，之后把压缩好的照片放入内存，最后内存转入表单下img.src，随着表单提交。

照片是自己用单反拍的，5M多，压缩下面3张分别是600多kb，400多kb，300kb的最后那张失真度很大了，压缩效率蛮高的。

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html><head><meta charset="utf-8" /><title>File API Test</title><script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script><style>#test {display: none;}</style></head><body><input type="file" id="fileImg"><form><img src="" id="test" alt=""></form><script>function handleFileSelect(evt) {// var filebtn = document.getElementById(id);// console.log(filebtn);// var files = filebtn.target.files;// console.log(filebtn.target);// console.log(files);var files = evt.target.files;for ( var i = 0, f; f = files[i]; i++) {// Only process image files.if (!f.type.match('image.*')) {continue;}var reader = new FileReader();// Closure to capture the file information.reader.onload = (function(theFile) {return function(e) {// Render thumbnail.// console.log(evt.target.files[0]);// console.log(e.target);console.log(e.target.result);var i = document.getElementById("test");i.src = event.target.result;console.log($(i).width());console.log($(i).height());$(i).css('width', $(i).width() / 10 + 'px');//$(i).css('height',$(i).height()/10+'px');console.log($(i).width());console.log($(i).height());var quality = 50;i.src = jic.compress(i, quality).src;console.log(i.src);i.style.display = "block";};})(f);// Read in the image file as a data URL.reader.readAsDataURL(f);}}document.getElementById('fileImg').addEventListener('change',handleFileSelect, false);var jic = {        /**         * Receives an Image Object (can be JPG OR PNG) and returns a new Image Object compressed         * @param {Image} source_img_obj The source Image Object         * @param {Integer} quality The output quality of Image Object         * @return {Image} result_image_obj The compressed Image Object         */         compress: function(source_img_obj, quality, output_format){                          var mime_type = "image/jpeg";             if(output_format!=undefined && output_format=="png"){                mime_type = "image/png";             }                           var cvs = document.createElement('canvas');             //naturalWidth真实图片的宽度             cvs.width = source_img_obj.naturalWidth;             cvs.height = source_img_obj.naturalHeight;             var ctx = cvs.getContext("2d").drawImage(source_img_obj, 0, 0);             var newImageData = cvs.toDataURL(mime_type, quality/100);             var result_image_obj = new Image();             result_image_obj.src = newImageData;             return result_image_obj;        }}</script></body></html>

在PC端是没有问题，手机端就获取不到data了，

整理至网络：

http://www.gbtags.com/gb/share/2991.htm

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