主要是利用html5的canvas来进行图片的压缩,然后转化为dataURL，再有dataURL转化为Blob文件，Blob对象可以直接赋值给Formdata.
app.service('Util', function($q) { var dataURItoBlob = function(dataURI) { // convert base64/URLEncoded data component to raw binary data held in a string var byteString; if (dataURI.split(',')[0].indexOf('base64') >= 0) byteString = atob(dataURI.split(',')[1]); else byteString = unescape(dataURI.split(',')[1]); // separate out the mime component var mimeString = dataURI.split(',')[0].split(':')[1].split(';')[0]; // write the bytes of the string to a typed array var ia = new Uint8Array(byteString.length); for (var i = 0; i < byteString.length; i++) { ia[i] = byteString.charCodeAt(i); } return new Blob([ia], { type: mimeString }); }; var resizeFile = function(file) { var deferred = $q.defer(); var img = document.createElement("img"); try { var reader = new FileReader(); reader.onload = function(e) { img.src = e.target.result; //resize the image using canvas var canvas = document.createElement("canvas"); var ctx = canvas.getContext("2d"); ctx.drawImage(img, 0, 0); var MAX_WIDTH = 800; var MAX_HEIGHT = 800; var width = img.width; var height = img.height; if (width > height) { if (width > MAX_WIDTH) { height *= MAX_WIDTH / width; width = MAX_WIDTH; } } else { if (height > MAX_HEIGHT) { width *= MAX_HEIGHT / height; height = MAX_HEIGHT; } } canvas.width = width; canvas.height = height; var ctx = canvas.getContext("2d"); ctx.drawImage(img, 0, 0, width, height); //change the dataUrl to blob data for uploading to server var dataURL = canvas.toDataURL('image/jpeg'); var blob = dataURItoBlob(dataURL); deferred.resolve(blob); }; reader.readAsDataURL(file); } catch (e) { deferred.resolve(e); } return deferred.promise; }; return { resizeFile: resizeFile }; });
由于目前angualrjs暂不支持通过multiform data上传文件，所以利用如下的代码可以上传formdata里的文件
app.controller('CompanyCtrl', function($http, Util) { Util.resizeFile(input.files[0]).then(function(blob_data) { var fd = new FormData(); fd.append("imageFile", blob_data); $http.post('http://your.domain.com/upload', fd, { headers: {'Content-Type': undefined }, transformRequest: angular.identity }) .success(function(data) { $scope.model.company_pict = data[0]; }) .error(function() { console.log("uploaded error...") }); }, function(err_reason) { console.log(err_reason); }); }
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