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。
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<html><head> <meta charset="utf-8"/> <title>File API Test</title> <script type="text/javascript" src="js/jquery-1.11.0.min.js"></script> <script type="text/javascript" src="js/JIC.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, ff = 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)</script></body></html>
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.naturalWidthcvs.height = source_img_obj.naturalHeightvar 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 = newImageDatareturn result_image_obj }, function ****(***)
