zoom function

from tkinter import *


class Zoom:
    def __init__(self):
        self.zoom_scale = 1
        self.zoom_count = 100
        self.font_name, self.font_size = 'Helvetica', 10

        self.master = Tk()
        self.master.title('ZOOM')

        self.text_widget_frame = Frame(self.master)
        self.text_widget = Text(master=self.text_widget_frame, bd=0, undo=True, wrap='none')
        self.vsb = Scrollbar(self.text_widget_frame, orient='vertical', command=self.text_widget.yview)
        self.hsb = Scrollbar(self.text_widget_frame, orient='horizontal', command=self.text_widget.xview)
        self.text_widget.configure(yscrollcommand=self.vsb.set, xscrollcommand=self.hsb.set)

        self.text_widget.grid(row=0, column=0, sticky='nsew')
        self.vsb.grid(row=0, column=1, sticky='ns')
        self.hsb.grid(row=1, column=0, sticky='ew')

        self.text_widget_frame.grid_rowconfigure(0, weight=1)
        self.text_widget_frame.grid_columnconfigure(0, weight=1)
        self.text_widget.focus_set()
        self.text_widget_frame.pack(side='top', fill='both', expand=True)

        self.button_frame = Frame(self.master, bg='grey')
        self.ZOOM_IN = Button(self.button_frame, text='ZOOM IN', command=self.zoom_in, bg='silver', fg='black', activebackground='silver', cursor='hand2')
        self.ZOOM_OUT = Button(self.button_frame, text='ZOOM OUT', command=self.zoom_out, bg='silver', fg='black', activebackground='silver', cursor='hand2')
        self.RESTORE_ZOOM = Button(self.button_frame, text='RESTORE ZOOM', command=self.restore_default_zoom, bg='silver', fg='black', activebackground='silver', cursor='hand2')
        self.ZOOM_LABEL = Label(self.button_frame, text='100%', bg='red', fg='white')

        self.ZOOM_IN.pack(side=LEFT, padx=5)
        self.ZOOM_OUT.pack(side=LEFT, padx=5)
        self.RESTORE_ZOOM.pack(side=LEFT)
        self.ZOOM_LABEL.pack(side=LEFT, padx=40)
        self.button_frame.pack(side=BOTTOM)

        self.master.config(bg='grey')
        self.master.mainloop()

    def zoom_in(self, event=None):
        if self.zoom_count != 500:  # 500% is the maximum perecentage to zoom-in
            self.zoom_scale += 1
            font_size = self.font_size + self.zoom_scale

            self.text_widget.tag_add('zoom', '1.0', END)
            self.text_widget.tag_config('zoom', font=(self.font_name, font_size))

            self.zoom_count += 10
            self.ZOOM_LABEL['text'] = f'{self.zoom_count}%'

            if self.zoom_count == 100:  # Remove 'zoom' tag when self.zoom_count reaches 100
                self.restore_default_zoom()

    def zoom_out(self, event=None):
        if self.zoom_count != 10:  # 10% is the minimum percentage to zoom-out
            if 'zoom' in self.text_widget.tag_names():
                self.zoom_scale -= 1

            else:  # This is to avoid font_size to become 0 when user tries to zoom out when there is no 'zoom' tag in text_widget
                self.zoom_scale -= 2

            font_size = self.font_size + self.zoom_scale

            if font_size != 0:
                self.text_widget.tag_add('zoom', '1.0', END)
                self.text_widget.tag_config('zoom', font=(self.font_name, font_size))

            self.zoom_count -= 10
            self.ZOOM_LABEL['text'] = f'{self.zoom_count}%'

            if self.zoom_count == 100:  # Remove 'zoom' tag when self.zoom_count reaches 100
                self.restore_default_zoom()

    def restore_default_zoom(self, event=None):
        self.zoom_scale = 1
        self.zoom_count = 100
        self.text_widget.tag_delete('zoom')
        self.ZOOM_LABEL['text'] = f'{self.zoom_count}%'


if __name__ == '__main__':
    Zoom()