The graphical user interface as a whole is represented by
Application class. Calling the
constructor initializes the application. See Section 11, “
class Application: The outermost frame”.
# - - - - - m a i n def main(): """Main program. [ display a graphical application that allows the user to test various fonts in various colors displayed on various background colors ] """ #-- 1 -- # [ the screen := the screen with a graphical application # app := the graphical application ] app = Application()
Before actually running the application, we need to place
the title of the application in the top-level window. This
title will be displayed in the decorations applied by the
user's window manager. The
.winfo_toplevel() method returns the top-level window of the application;
.title() method sets the title in that
window. If we don't do this, the default window title will
be just “tk”.
#-- 2 -- # [ app := app with its window title set to the name of # this application ] app.winfo_toplevel().title( "%s %s" % (PROGRAM_NAME, EXTERNAL_VERSION) )
.mainloop() method starts the
application running. It will respond to events until the
user terminates it by clicking the button.
#-- 3 -- # [ app := app responding to user events ] app.mainloop()