How to make application launch on linux without downloads?

Question

linux

There is a task: to write an application on linux, so that it displays information on the monitor.
Therefore, it is necessary that the application displays the window in full screen at once, when it is turned on. No loading animations, welcome screens, desktop, etc.
Ideally, the console screen and immediately after it the application interface.
I'm not familiar with linux, but I'm sure it can be done. Tell me where to dig?
PS the application will be in python using QT, in the form of a "computer" there will be a Raspberry board

Answer 1

write a script for systemd.
display the application stdout on the first console.
in the systemd mana there is a description of how to display.
to taste shamanize with getty so that the input from the first console is not requested.
if you're talking about autorun applications with a graphical interface, then google "linux kiosk-mode" options in the sea.

Answer 2

What you are looking for is called a kiosk. Here is the first link I came across to an article about creating a kiosk with a Qt application for the Raspberry Pi.
The most technologically primitive option is to run the program immediately after the OS boots, configuring it to be displayed in the framebuffer (fbdev). Qt5 supports this. You don't need X or Wayland for this, but hardware acceleration will work.
The classic "correct" option is to make an X session (x session) that starts only your application, and boot into it automatically.