Function createThumbnail

src/js/functions.js:3893–3923

(file, max)

}

function createThumbnail(file, max) {
  return new Promise(function (resolve, reject) {
    var reader = new FileReader();
    reader.onload = function (event) {
      var img = new Image();
      img.onload = function () {
        if (img.width > max) {
          var oc = document.createElement('canvas');
          var octx = oc.getContext('2d');
          oc.width = img.width;
          oc.height = img.height;
          octx.drawImage(img, 0, 0);
          if (img.width > img.height) {
            oc.height = (img.height / img.width) * max;
            oc.width = max;
          } else {
            oc.width = (img.width / img.height) * max;
            oc.height = max;
          }
          octx.drawImage(oc, 0, 0, oc.width, oc.height);
          octx.drawImage(img, 0, 0, oc.width, oc.height);
          resolve(oc.toDataURL());
        } else {
          resolve(img.src);
        }
      };
      img.src = event.target.result;
    };
    reader.readAsDataURL(file);
  });
}

function dataURItoBlob(dataURI) {
  var byteString = atob(dataURI.split(',')[1]);