Jquery Dropzone.js change thumbnail width to 100%

Question

I am using Dropzone.js to allow users to upload files to server, according to the specs you can change the thumbnail width as shown below, however I want to change the width to 100% instead of using px, Is this possible?

Because if I do thumbnailWidth: 100% it will not recognize % char.

    dzImageOptions = Dropzone.options.myDropzone = {
        thumbnailWidth: 314, //I want to change width to 100% instead
        thumbnailHeight: 314,
        init: function (file) {

        }
}
    //Also have to change css or thumbnail won't resize properly
    .dropzone.song-image .dz-preview .dz-image {
    border-radius: 1px;
    width: 314px;
    height: 314px;
}

<div class="dropzone song-image"></div>

Answer 1

You cannot specify a percentage on thumbnailWidth and thumbnailHeight. Dropzone uses these values to create the image source to show it as a preview.

But you can leave the thumbnail at the original width and height, setting these values to null(Note that this can cause a bit of lag with high resolution images) and then use the <img> width and height attributes to display the image with the size you want and adjusting the .dz-image container with css.

html:

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

js:

Dropzone.autoDiscover = false;

Dropzone.options.myDropzone = {
    url: "yourUrl",
    thumbnailWidth: null,
    thumbnailHeight: null,
    init: function() {
        this.on("thumbnail", function(file, dataUrl) {
            $('.dz-image').last().find('img').attr({width: '100%', height: '100%'});
        }),
        this.on("success", function(file) {
            $('.dz-image').css({"width":"100%", "height":"auto"});
        })
    }
};

var myDropzone = new Dropzone('div#myDropzone');

Answer 2

I needed to accomplish responsive thumbnails with dropzone and this post helped a lot. I also needed to do it without jquery, so here's what I came up with. Figured I'd share if it helps anyone else.

My dropzone init function looks like this:

init: function () {
    this.on('thumbnail', function(file, dataUrl) {
        var thumbs = document.querySelectorAll('.dz-image');
        [].forEach.call(thumbs, function (thumb) {
            var img = thumb.querySelector('img');
            if (img) {
                img.setAttribute('width', '100%');
                img.setAttribute('height', '100%');
            }
        });
    }),
    this.on('success', function(file) {
        var thumbs = document.querySelectorAll('.dz-image');
        [].forEach.call(thumbs, function (thumb) {
            thumb.style = 'width: 100%; height: auto;';
        });
    })
}

I'm not a javascript wizard so there is probably a more efficient or better way to do this. Please share!