Whiteboard tkinter

 #=======imports=======#

from tkinter import *

from tkinter.colorchooser import askcolor

root=Tk()

## variable defining####

colour="blue"

#========Theme Bacground========#

def changeBg():

        (triple, hexstr) = askcolor()

        if hexstr:

         canvas.config(background=hexstr)

def Light():

        root.title("Alvin's Whiteboard")

        canvas.config(background="white")

        

def Dark():

     root.title("Alvin's blackboard")

     canvas.config(background="black")

#========fg colour===========#

def changeFg():

        global colour

        (triple, hexstr) = askcolor()

        if hexstr:

         colour=hexstr

def blue():

 global colour

 colour="blue"

def white():

 global colour

 colour="white"

def red():

 global colour

 colour="red"

def black():

 global colour

 colour="black"

                    

#=======line creating=========#

def paint(event, selected_colour):

    '''Draws a line following the user mouse cursor'''        

    x1,y1=event.x,event.y

    x2, y2 = event.x-1, event.y

    canvas.create_line(x1,y1,x2,y2, fill=selected_colour, width=s1.get(),capstyle=ROUND,smooth=True)

    

# basic size and name of GUI

can_width=1040

can_height=1790

root.geometry(f"{can_width}x{can_height}")

root.minsize(width=500,height=500)

root.title("Alvin's board")

#======width scale=====#

s1=Scale(root,from_=8,to=25,orient=HORIZONTAL)

s1.pack(anchor="n",ipadx=840,side="top")

#========creating Canvas===========#

canvas = Canvas(root,width=can_width,height=can_height, background='black')

canvas.pack(fill="both")

canvas.bind("<Motion>", lambda event: paint(event,selected_colour=colour))

#=========creating main menu=========#

mainMenu=Menu(root)

#========creating sub menus==========#

m1=Menu(mainMenu)

m2=Menu(mainMenu)

m3=Menu(mainMenu)

mainMenu.add_cascade(label="Colour",menu=m1)

mainMenu.add_cascade(label="Theme",menu=m2)

mainMenu.add_cascade(label="Erase",menu=m3)

#====adding command in menu m1=====#

m1.add_command(label=" ",background="white",command=white)

m1.add_command(label=" ",background="blue",command=blue)

m1.add_command(label=" ",background="red",command=red)

m1.add_command(label=" ",background="black",command=black)

m1.add_command(label="Other",command=changeFg)

#====adding command in menu m2=====#

m2.add_command(label=" ",background="white",command=lambda : canvas.config(background="white"))

m2.add_command(label=" ",background="black",command=lambda : canvas.config(background="black"))

m2.add_command(label="Other",command=changeBg)

#======adding command in menu m3====#

m3.add_command(label="Clear canvas",command=lambda: canvas.delete("all"))

#=========configing Menu===========#

root.config(menu=mainMenu)

#========running mainloop========#

root.mainloop()