As already answered there is no size
parameter for the sg.popup()
function and you can use spaces and empty strings like paddings this way:
import PySimpleGUI as sg
# blanks like paddings example
sg.popup("", " Hello! \x00", "")
the empty strings before and after Hello! behave like vertical padding while the spaces inside Hello! string behave like horizontal padding.
Now you could ask why the hex escape character \x00
?
It's the workaround I found, stands for the Null character and without it doesn't pad on the right.