Compress the image file on the angularjs client and then upload it,

Compress the image file on the angularjs client and then upload it,

We mainly use html5 canvas to compress images, convert them to dataURL, and convert them to Blob files. Blob objects can be directly assigned to 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    };});

Currently, angualrjs does not support uploading files through multiform data, so you can use the following code to upload files in formdata.

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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