Future<Uint8List> to Base64 or PNG in Flutter

Question

I need to convert a Future<Uint8List> to Base64 or PNG in Flutter, I am using this pub to get signature and export it but when I call toPngBytes() method (method in pub) it returns a Future<Uint8List> and I need to convert it to Base64 format or List<int> at least ByteData format, I can not convert it to a more usable format for me, can anyone help me to resolve this.

_controller.toPngBytes(); // _controller is a variable that holds info about my signature.

Answer 1

import 'dart:convert';

// async variant
final imageData = await _controller.toPngBytes(); // must be called in async method
final imageEncoded = base64.encode(imageData); // returns base64 string

// callback variant
_controller.toPngBytes().then((data) {
 final imageEncoded = base64.encode(data); 
});