dropzone-cropper.js

// 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');
    });
});

Hi, a very awesome documentation, but i believe th emodal section is missing, so how do get the code in, cos i have no idea hat its like

Oh never mind i finally got to the bottom of it....thanks for this

Any html example working?

Cool thank u!!!

+1 for demo

working demo, not cropperjs, but worked: slimimagecropper.com

@tozyne could you post your modal or explain what to do?

Hi! somebody can help me to use this code? my modal dont show the cropper, not even the selected image .. please help!

Here's an example with the modal HTML for anyone needing it. Some of the script has been changed since this is from a project of mine the modal should work fine with the code above, just the selector might need to change

https://gist.github.com/BrettGregson/a4f8fc422556a447e50f3da33f3d175e

@BrettGregson Thank you! ill try with your changes too

Thanks, helped a lot.
Full example:
https://github.com/4unkur/cropper_dropzone

File became too big (from3.4mb to 18mb)

@Saymecode, i have the same problem. I'm uploading a file with 107.5 kB and 1368 x 1026px and the content of the request is being sended with 1205213 kb (1.2mb).

Because of that my server is throwing an error called "Request Entity Too Long" (http 413).

Someone knows how can i fix it?

@danilosantosdev you can solve it by changing line (72) var blob = $img.cropper('getCroppedCanvas').toDataURL(); to var blob = $img.cropper('getCroppedCanvas').toDataURL("image/jpeg"); because the default is probably a PNG, which increases the size of that blob.

@schimini, thanks, this helped!

For those getting high Image size, just set .toDataURL("image/jpeg","0.9") to a more reasonable file size.

Hey there im getting a error in the $img.cropper part, saying that $img.cropper is not a a function.

Any ideas? what version of cropper did you guys use?

Figured my whole problem was that I wasn't using the right script. I had to use jquery-cropper to get it working.

https://github.com/fengyuanchen/jquery-cropper

good work.

Helped me a lot

Hello ,i have use this code everything is working fine but modal popup is not working how i can crop image please suggest .

Thanks.

@maria-p

It seem to be working very well with single image. Did you try with multiple images ?

Here's an example with the modal HTML for anyone needing it. Some of the script has been changed since this is from a project of mine the modal should work fine with the code above, just the selector might need to change

https://gist.github.com/BrettGregson/a4f8fc422556a447e50f3da33f3d175e

This link is broken.. Can you please provide the working link?