PySimpleGUI/DemoPrograms/Demo_Theme_Previewer_Dark.py

import PySimpleGUI as sg
# import PySimpleGUIWeb as sg
# import PySimpleGUIQt as sg

"""
    If you're using the PySimpleGUI color themes, then your code will a line that looks something like this:
        sg.theme('Light Green 1') or sg.theme('LightGreen1')
        
    This demo shows how to access the list of all "dark themes" as an example of how you can build your own previewer
    
    Copyright 2020 PySimpleGUI.org
"""

# Use the built-in Theme Viewer to show all of the themes and their names
# sg.theme_previewer()

# The remainder of the program duplicates the built-in Theme Viewer, allowing you to create your
# own custom theme viewer window.  You can configure the number of frames per row for example. Or maybe you only
# want to see the dark themes

window_background = 'black'

def sample_layout():
    """
    Creates a small window that will represent the colors of the theme. This is an individual theme's preview
    :return: layout of a little preview window
    :rtype: List[List[Element]]
    """
    return [[sg.Text('Text element'), sg.InputText('Input data here', size=(15, 1))],
            [sg.Button('Ok'), sg.Button('Cancel'), sg.Slider((1, 10), orientation='h', size=(10, 15))]]


layout = [[sg.Text('List of Dark Themes Provided by PySimpleGUI', font='Default 18', background_color=window_background)]]

FRAMES_PER_ROW = 9
names = [name for name in sg.theme_list()  if 'dark' in name.lower()]       # get list of only "dark" themes
row = []
for count, theme in enumerate(names):
    sg.theme(theme)
    if not count % FRAMES_PER_ROW:
        layout += [row]
        row = []
    row += [sg.Frame(theme, sample_layout())]
if row:
    layout += [row]

sg.Window('Custom Preview of Themes', layout, background_color=window_background).read(close=True)