Python 3 Tkinter Borderless fullscreen application

To fix your OS-X Problem i will provide a solution that fixes a similar problem for me. (Had some Issues using fullscreen in between Linux and Windows)

You wanted to get rid of the Window Managers Bar? Take a look at the docs it states an option that removes the window managers items by using -toolwindow option.

Concerning the size of your Application here is what helped me using linux - a "manual zoom":

class MyClass(tk.Tk):    def __init__(self, *args, **kwargs):        tk.Tk.__init__(self, *args, **kwargs)        self.overrideredirect(True) # depending on your needs        self.attributes("-toolwindow", 1) # this line removes the window managers bar        try:                                   # Automatic zoom if possible            self.wm_state("zoomed")            print("Using automatic zoom")        except tk.TclError:                    # Manual zoom            # Bad Argument Error is a TclError            print("Using manual zoom")            # get the screen dimensions            width = self.winfo_screenwidth()            height = self.winfo_screenheight()            # build a geometry string.             # form: width x height + x_offset + y_offset            geom_string = "%dx%d+0+0" % (width, height)            self.wm_geometry(geom_string)

Please note that I am not using an unconfigured tk.Tk() - Instance here - my class is the tk.Tk() - Instance. So I do not need to overwrite the parent but only "myself" speaking of the POV of the class.

#!/usr/bin/pythonimport Tkinter as tkclass App(tk.Frame):    def __init__(self, parent, *args, **kwargs):        tk.Frame.__init__(self, parent)        self.parent = parent        self.initUI()    def initUI(self):        self.parent.title("Fullscreen Application")        self.pack(fill="both", expand=True, side="top")        self.parent.wm_state("zoomed")        self.parent.bind("<F11>", self.fullscreen_toggle)        self.parent.bind("<Escape>", self.fullscreen_cancel)        self.fullscreen_toggle()        self.label = tk.Label(self, text="Fullscreen", font=("default",120), fg="black")        self.label.pack(side="top", fill="both", expand=True)    def fullscreen_toggle(self, event="none"):        self.parent.focus_set()        self.parent.overrideredirect(True)        self.parent.overrideredirect(False) #added for a toggle effect, not fully sure why it's like this on Mac OS        self.parent.attributes("-fullscreen", True)        self.parent.wm_attributes("-topmost", 1)    def fullscreen_cancel(self, event="none"):        self.parent.overrideredirect(False)        self.parent.attributes("-fullscreen", False)        self.parent.wm_attributes("-topmost", 0)        self.centerWindow()    def centerWindow(self):        sw = self.parent.winfo_screenwidth()        sh = self.parent.winfo_screenheight()        w = sw*0.7        h = sh*0.7        x = (sw-w)/2        y = (sh-h)/2        self.parent.geometry("%dx%d+%d+%d" % (w, h, x, y))if __name__ == "__main__":    root = tk.Tk()    App(root).pack(side="top", fill="both", expand=True)    root.mainloop()