I have a situation here.
I need to print an invoice. And, on the same invoice I need to print the 2D barcode. Now, in the before.layout of the field.<field_name>, I am calling the exe, which prints the barcode. I am using app_start() here. This barcode is needed at the bottom of the invoice.
But, the problem here is that, before the data is printed on the invoice, the barcode gets printed, i.e., at the start of the invoice!!