PosColumn alignment inside row not working

[noebt]

Hi, I have a row with three columns. I want to align one to the right and I use the example. but it doesn't work, it just puts all the columns together with no alignment.
Anyone know why?
Thanks.

bytes += ticket.row([
        PosColumn(text: element.cantidad.toString() + ' x ' + element.nombre!,width: 4, styles: PosStyles(height: PosTextSize.size1, width: PosTextSize.size1, codeTable: 'CP1252')),
        PosColumn(text: " " * espacios, width: 6, styles: PosStyles(height: PosTextSize.size1, width: PosTextSize.size1)),
        PosColumn(width: 2, textEncoded: Uint8List.fromList(element.precioArticulo.toString().codeUnits + [128]), styles: PosStyles(codeTable: 'CP1252', align: PosAlign.right)),
      ]);