When you try to print to the default printer the system returns the following error:
[WARNING] Gtk (CRITICAL): gtk_page_setup_get_paper_size: assertion 'GTK_IS_PAGE_SETUP (setup)' failed
[WARNING] Gtk (CRITICAL): IA__gtk_page_setup_get_paper_size: assertion 'GTK_IS_PAGE_SETUP (setup)' failed
When i use PrintRequester() it prints without problems. In my case I need to print without the interference of the user, because it is a POS software with many impressions. My system already prints using ESC / POS, however, the company wants to use a low-cost printer that can only print QRCode via spooler.