dataURItoBlob(dataURI) {
const byteString = window.atob(dataURI);
const arrayBuffer = new ArrayBuffer(byteString.length);
const int8Array = new Uint8Array(arrayBuffer);
for (let i = 0; i < byteString.length; i++) {
int8Array[i] = byteString.charCodeAt(i);
}
const blob = new Blob([int8Array], { type: 'image/png' });
return blob;
}