from Tkinter import*

def return_crop(window):
    x1, y1 = window.a.get(), window.b.get()
    x2, y2 = window.c.get(), window.d.get()
    return (x1,y1,x2,y2)
      

def prompt_crop():
    crop_window = Tk()
    
    crop_frame = Frame(crop_window)
    crop_frame.pack()
    
    title = Label(crop_frame, text='CROP IMAGE')
    title.grid(row=0, columnspan=4)
    
    crop_window.a = IntVar()
    
    top_x_label = Label(crop_frame, text="Top left corner x: ")
    top_x_label.grid(row=1, column=0) 
    top_x_entry = Entry(textvariable=crop_window.a)
    top_x_entry.grid(row=1, column=1)
    
    crop_window.b = IntVar()
    
    top_y_label = Label(crop_frame, text="Top left corner y: ")
    top_y_label.grid(row=1, column=2) 
    top_y_entry = Entry(textvariable=crop_window.b)
    top_y_entry.grid(row=1, column=3)
    
    crop_window.c = IntVar()

    low_x_label = Label(crop_frame, text="Lower right corner x: ")
    low_x_label.grid(row=2, column=0) 
    low_x_entry = Entry(textvariable=crop_window.c)
    low_x_entry.grid(row=2, column=1)
    
    crop_window.d = IntVar()    
    
    low_y_label = Label(crop_frame, text="Lower right corner y: ")
    low_y_label.grid(row=2, column=2) 
    low_y_entry = Entry(textvariable=crop_window.d)
    low_y_entry.grid(row=2, column=3)

    get_values = lambda : return_crop(crop_window)    
    
    submit_button = Button(crop_frame, text="Submit", command=lambda : get_values())
    submit_button.grid(row=3, columnspan=4)

    
    crop_window.mainloop()

if __name__ == '__main__':
    prompt_crop()