The idea of using "Look and Feel" settings goes way back with PySimpleGUI. You may have seen the green and tan colors windows from time to time. It's a feature that wasn't put into very many of the demo programs.

Because the demos are often the starting point for projects, it made sense to begin to spice things up a little and add color right from the start. Not everyone will be pleased with the color selection. You can always remove the call entirely (it's 1 line of code), or choose another one. Point is they are coming to a screen near you.

Previously you needed to specify the exact name of the Theme. Now it's a "Fuzzy" match. "Grey Dark 2" or "DarkGray2" both work. The original 28 Themes are sill available using the old names. They are also available using a new naming convention. The new convention is:

<"Dark" | "Light"> <Color> [#]

Where color can be: Black, Blue, Green, Teal, Brown, Yellow, Grey, Purple

Not all combinations are represented and now every combination has the same number of choices as others. For example there are 9 Dark Blue themes and 1 Light Yellow.

You can get a text list of the choices by calling:

import PySimpleGUI as sg
sg.list_of_look_and_feel_values()

You will also get this text list on your console if you pass in a value that doesn't match a valid Theme.

You can also get a visual dump of the choices by calling:

sg.preview_all_look_and_feel_themes()

With the straight PySimpleGUI port (tkinter), the preview looks like this:

You can use these on the Qt and Web ports as well. The same values work and you can also make the same preview call. for the PySimpleGUIWeb port, the preview looks like this:

Putting these color themes to use is as simple as adding this line of code to your program, any place prior to creating your layout or calling a popup:

sg.change_look_and_feel('Theme Name Here') 

Note that this possibly a first step in creating a nice looking window. It is merely settings up some colors for you. There is more you can do to polish your window should you wish. The idea here is for people to take a break from creating and looking at gray windows all the time, especially when starting out.

If your program only has popup calls, that's OK, changing the Look and Feel changes the colors for all future windows (until another change is made).

If you have additional color scheme ideas, there is a defined format so that you can add your own by adding a dictionary entry into the Theme table.