Tkinter Python 3 scaling issue on MacOS

I have the exact same problem!! It would always be a little short, no matter what I tried.

In the end, this is what I did. See if it works for you.

from tkinter import *
window = Tk()
window.title("Whatever you want")

window.focus()

HEIGHT = window.winfo_screenwidth()
WIDTH = window.winfo_screenheight()
RESOL = str(HEIGHT) + "x" + str(WIDTH+7) + "+" + str(-7) + "+" + str(0)
window.geometry(RESOL)

Hope this helps you!

So the solution, as @Bryan Oakley proposed, is juste to change the size of the default fonts on Mac OS. Now I wanted something user friendly, as I noticed the result on my macbook was also different from the one given by the user.

I chose to use a Scale Tkinter component to allow the user to change the size of the font himself :

EDIT : kept for the sake of the solution, but actually the Scale widget doesn't seem to be compatible with all MacOS version either, as it doesn't appear at all on some of them.

First initialization of the GUI :

class GUI():

MACOS_DEFAULT_FONT_SIZE = 7
DEFAULT_FONT_SIZE = 9      

def __init__(self,scriptDir,logger,title) :        
    self.scriptDir = scriptDir
    
    self.window = Tk.Tk()
    self.window.resizable(False,False)        
    self.startFontSize = self.DEFAULT_FONT_SIZE        
    
    if platform.system() == 'Windows' :
        self.window.iconbitmap('bestarcade.ico')
    elif platform.system() == 'Darwin' :
        # Handle tkinter font size bug on MacOS
        self.startFontSize = self.MACOS_DEFAULT_FONT_SIZE
        
    self.setFontSize(self.startFontSize)
    self.window.title(title)        
    self.logger = logger

def draw(self) :
    self.root = Tk.Frame(self.window,padx=10,pady=5)
    self.root.grid(column=0,row=0)
    self.drawSliderFrame()
    self.drawMainframe()
    self.window.mainloop()

Then in the same class, creation of the scale component and its event handler (also used during initialization of the GUI) :

def setFontSize(self, value) :        
    default_font = Font.nametofont("TkDefaultFont")
    default_font.configure(size=value)
    text_font = Font.nametofont("TkTextFont")
    text_font.configure(size=value)
    fixed_font = Font.nametofont("TkFixedFont")
    fixed_font.configure(size=value)

def drawSliderFrame(self) :
    self.sliderFrame = Tk.Frame(self.root,padx=10,pady=0)
    self.sliderFrame.grid(column=0,row=0,sticky="EW",pady=0)
    self.sliderFrame.grid_columnconfigure(0, weight=1)
    self.slider = Tk.Scale(self.sliderFrame, from_=4, to=12, orient=Tk.HORIZONTAL, showvalue=0, command=self.setFontSize)
    wckToolTips.register(self.slider, 'Window Size') #TODO internationalization
    self.slider.grid(column=0,row=0,sticky="W",pady=0)
    self.slider.set(self.startFontSize)

This seems to work well, although it does not resolve all issues around resolution and size of the screen Size of the windows might have to be reduced at little more than what is done automatically, too

Here it is at default size (9) :

and here modified with the scale to size 7 :