PySimpleNoGUI

PySimpleNoGUI is a mock-up module that overrides PySimpleGUI and MySimpleGUI.

PySimpleNoGUI transparently runs a GUI app built with PySimpleGUI as a CLI program, without creating any graphical elements on the screen. It allows you to run a GUI program in a text-only terminal and without consuming memory/cpu.

Since PySimpleNoGUI overrides all required variables and functions, there is no need to install any GUI library on the running platform (no need to install PySimpleGUI, Tkinter, PyQt, etc.).

This is an ideal solution for programs that open a GUI screen for the user to set up a certain set of parameters and then execute something. With PySimpleNoGUI, the program can load a preconfigured setting of the GUI and immediately start the execution. All updates to Multiline elements will appears in stdout (via print).

The code will run the same but without creating any GUI. You are not required to change anything in the code and you can switch back and forth between PySimpleGUI and PySimpleNoGUI seamlessly. All the elements have the same values and are retrievable using sg['element_name'].get() or sg.element_name.get(), and similarly updated with the method update(), just like you do with PySimpleGUI and MySimpleGUI.

Installation

You can install PySimpleNoGUI by downloading the file PySimpleNoGUI.py from this repository.

Usage

Integration in your code

Instead of:

import PySimpleGUI

use:

if terminal_mode:  # some boolean flag
    import PySimpleNoGUI as sg
else:
    import PySimpleGUI as sg

(PySimpleNoGUI works also with import MySimpleGUI as sg).

System-dependent activation

The flag terminal_mode can be set to anything. You can set it in the static code (as above) or make it system-dependent, such as here:

def is_raspbian():
    res = False
    if platform.lower() == 'linux':
        with open('/etc/os-release', 'r') as f:
            s = f.read()
        i = s.find('\nID=') + 4
        ii = s.find('\n', i)
        linux_sys = s[i:ii]
        res = linux_sys.lower() == 'raspbian'

    return res


terminal_mode = is_raspbian()

In this example, the code automatically sets terminal_mode to True if running in Raspberry Pi, and the code will run without PySimpleGUI and without generating costly GUI elements. (Obviously RPi can run GUI, but you can save a lot of ram/cpu resources by running apps as GUI-less. It will also run on a RPi Lite without any GUI libraries installed).

Loading preconfigured settings

You would probably want to have some control over the values of the GUI elements.

The way to do this is with the save/load settings routines. Check out example in the PySimpleGUI Cookbook or the Demo.py file included in this repository.

Activating your code automatically without GUI

In some cases, you would need to emulate clicking a button element in the window in order to activate the main routine in your program. For this, add the keyword parameter metadata='auto_activate' in the element creation, such as here:

sg.Button('Run', key='button_key', metadata='auto_activate')

PySimpleNoGUI will remember all the elements with metadata='auto_activate' and will send them back as the return value of event on each call to window.read().

This works for multiple elements in a sequence. This means that the first element created with metadata='auto_activate' will be returned in the first event call.

To Do

Right now the constants used in Tkinter and PySimpleGUI are statically defined. In order to keep up with future changes, it is desirable to add a dynamic import of these definitions: on first run, these will be downloaded from GitHub and written locally.

Another improvement would be to first use a parser and tokenize the code in order to locate all the uses of sg in the text in order to extract the specific calls to PySimpleGUI. This would be the most efficient way for handling all calls to PySimpleGUI. I did not look into parsing the code, but might do this in the future.

Issues and Features

The most common issue that might come up when running PySimpleNoGUI for the first time is having the code break because of unknown function calls and elements. The reason for this is that PySimpleGUI uses multiple names for common functions and elements, some of which are not yet included in PySimpleNoGUI.

It is very easy to fix such breaks: just add the missing item to the respective tuples, either empty_func_list, empty_consts_list , or elements_list.

Note that because different elements have specific behaviors, I creates elements_aliases, which is a dictionary that matches additional names to already existing elements (e.g., Input is just another alias for InputText).

Or you can write me about adding/fixing something.

That's it!