Mit cropper.js vor Dropzone.js Bild senden zum server

Werden Sie wahrscheinlich nicht brauchen es nicht mehr, aber ich lass es jetzt hier 🙂

War es ein bisschen schwierig, und meine Lösung ist wahrscheinlich irgendwie "hackish", aber es funktioniert und Sie nicht haben, um das hochladen von Dateien auf den server zu ändern.

Ich bin auch mit cropper in einem modalen Fenster. Ich wollte zu force user zu beschneiden, um eine bestimmte Abmessungen vor dem hochladen auf server.

Nachdem Sie bestätigen Ernte in einem modalen Bild wird sofort hochgeladen.

//transform cropper dataURI output to a Blob which Dropzone accepts
function dataURItoBlob(dataURI) {
    var byteString = atob(dataURI.split(',')[1]);
    var ab = new ArrayBuffer(byteString.length);
    var ia = new Uint8Array(ab);
    for (var i = 0; i < byteString.length; i++) {
        ia[i] = byteString.charCodeAt(i);
    }
    return new Blob([ab], { type: 'image/jpeg' });
}

//modal window template
var modalTemplate = '<div class="modal"><!-- bootstrap modal here --></div>';

//initialize dropzone
Dropzone.autoDiscover = false;
var myDropzone = new Dropzone(
    "#my-dropzone-container",
    {
        autoProcessQueue: false,
        //..your other parameters..
    }
);

//listen to thumbnail event
myDropzone.on('thumbnail', function (file) {
    //ignore files which were already cropped and re-rendered
    //to prevent infinite loop
    if (file.cropped) {
        return;
    }
    if (file.width < 800) {
        //validate width to prevent too small files to be uploaded
        //.. add some error message here
        return;
    }
    //cache filename to re-assign it to cropped file
    var cachedFilename = file.name;
    //remove not cropped file from dropzone (we will replace it later)
    myDropzone.removeFile(file);

    //dynamically create modals to allow multiple files processing
    var $cropperModal = $(modalTemplate);
    //'Crop and Upload' button in a modal
    var $uploadCrop = $cropperModal.find('.crop-upload');

    var $img = $('<img />');
    //initialize FileReader which reads uploaded file
    var reader = new FileReader();
    reader.onloadend = function () {
        //add uploaded and read image to modal
        $cropperModal.find('.image-container').html($img);
        $img.attr('src', reader.result);

        //initialize cropper for uploaded image
        $img.cropper({
            aspectRatio: 16 / 9,
            autoCropArea: 1,
            movable: false,
            cropBoxResizable: true,
            minContainerWidth: 850
        });
    };
    //read uploaded file (triggers code above)
    reader.readAsDataURL(file);

    $cropperModal.modal('show');

    //listener for 'Crop and Upload' button in modal
    $uploadCrop.on('click', function() {
        //get cropped image data
        var blob = $img.cropper('getCroppedCanvas').toDataURL();
        //transform it to Blob object
        var newFile = dataURItoBlob(blob);
        //set 'cropped to true' (so that we don't get to that listener again)
        newFile.cropped = true;
        //assign original filename
        newFile.name = cachedFilename;

        //add cropped file to dropzone
        myDropzone.addFile(newFile);
        //upload cropped file with dropzone
        myDropzone.processQueue();
        $cropperModal.modal('hide');
    });
});

Für Entwickler, die nicht wollen oder nicht können, haben die jQuery-Abhängigkeit.

Ich habe mir vor kurzem geschrieben Artikel über die Integration von Dropzone mit Cropper.js, kann es nützlich sein. Siehe code-Schnipsel aus dem Artikel unten.

Den HTML -

<div class="dropzone" id="myDropzone"></div>

JavaScript

Dropzone.options.myDropzone = {
    url: '/post',
    transformFile: function(file, done) {

        var myDropZone = this;

        //Create the image editor overlay
        var editor = document.createElement('div');
        editor.style.position = 'fixed';
        editor.style.left = 0;
        editor.style.right = 0;
        editor.style.top = 0;
        editor.style.bottom = 0;
        editor.style.zIndex = 9999;
        editor.style.backgroundColor = '#000';

        //Create the confirm button
        var confirm = document.createElement('button');
        confirm.style.position = 'absolute';
        confirm.style.left = '10px';
        confirm.style.top = '10px';
        confirm.style.zIndex = 9999;
        confirm.textContent = 'Confirm';
        confirm.addEventListener('click', function() {

            //Get the canvas with image data from Cropper.js
            var canvas = cropper.getCroppedCanvas({
                width: 256,
                height: 256
            });

            //Turn the canvas into a Blob (file object without a name)
            canvas.toBlob(function(blob) {

                //Update the image thumbnail with the new image data
                myDropZone.createThumbnail(
                    blob,
                    myDropZone.options.thumbnailWidth,
                    myDropZone.options.thumbnailHeight,
                    myDropZone.options.thumbnailMethod,
                    false, 
                    function(dataURL) {

                        //Update the Dropzone file thumbnail
                        myDropZone.emit('thumbnail', file, dataURL);

                        //Return modified file to dropzone
                        done(blob);
                    }
                );

            });

            //Remove the editor from view
            editor.parentNode.removeChild(editor);

        });
        editor.appendChild(confirm);

        //Load the image
        var image = new Image();
        image.src = URL.createObjectURL(file);
        editor.appendChild(image);

        //Append the editor to the page
        document.body.appendChild(editor);

        //Create Cropper.js and pass image
        var cropper = new Cropper(image, {
            aspectRatio: 1
        });

    }
};

Eine demo der integration der code kann hier gefunden werden:
https://codepen.io/rikschennink/pen/PXQNGp?editors=0010