main.py

import customtkinter
import os
from PIL import Image


class App(customtkinter.CTk):
    def __init__(self):
        super().__init__()

        self.title("ОтрубИ")
        self.geometry("700x450")

        # set grid layout 1x2
        self.grid_rowconfigure(0, weight=1)
        self.grid_columnconfigure(1, weight=1)

        # create navigation frame
        self.navigation_frame = customtkinter.CTkFrame(self, corner_radius=0)
        self.navigation_frame.grid(row=0, column=0, sticky="nsew")
        self.navigation_frame.grid_rowconfigure(4, weight=1)

        self.navigation_frame_label = customtkinter.CTkLabel(
            self.navigation_frame,
            text="Главное меню",
            compound="left",
            font=customtkinter.CTkFont(size=15, weight="bold")
        )
        self.navigation_frame_label.grid(row=0, column=0, padx=20, pady=20)

        self.home_button = customtkinter.CTkButton(
            self.navigation_frame,
            corner_radius=0,
            height=40,
            border_spacing=10,
            text="Обработка строк",
            fg_color="transparent",
            text_color=("gray10", "gray90"),
            hover_color=("gray70", "gray30"),
            anchor="w",
            command=self.home_button_event)
        self.home_button.grid(row=1, column=0, sticky="ew")

        self.frame_2_button = customtkinter.CTkButton(
            self.navigation_frame,
            corner_radius=0,
            height=40,
            border_spacing=10,
            text="Обработка документа",
            fg_color="transparent",
            text_color=("gray10", "gray90"),
            hover_color=("gray70", "gray30"),
            anchor="w",
            command=self.frame_2_button_event)
        self.frame_2_button.grid(row=2, column=0, sticky="ew")

        self.appearance_mode_menu = customtkinter.CTkOptionMenu(self.navigation_frame, values=["Light", "Dark", "System"],
                                                                command=self.change_appearance_mode_event)
        self.appearance_mode_menu.grid(row=6, column=0, padx=20, pady=20, sticky="s")

        # create home frame
        self.home_frame = customtkinter.CTkFrame(self, corner_radius=0, fg_color="transparent")
        self.home_frame.grid_columnconfigure(0, weight=1)

        self.home_frame_label = customtkinter.CTkLabel(self.home_frame, text="Преобразование текста")
        self.home_frame_label.grid(row=0, column=0, padx=20, pady=10)

        self.home_text_in = customtkinter.CTkTextbox(self.home_frame, width=400, height=150, corner_radius=0)
        self.home_text_in.grid(row=1, column=0, padx=10, pady=10)
        self.home_text_in.insert("0.0", "Текст для преобразования")

        self.home_frame_button_process = customtkinter.CTkButton(self.home_frame, text="Process", compound="right", command=self.button_process_event)
        self.home_frame_button_process.grid(row=2, column=0, padx=10, pady=10)

        self.home_text_out = customtkinter.CTkTextbox(self.home_frame, width=400, height=150, corner_radius=0)
        self.home_text_out.grid(row=3, column=0, padx=10, pady=10)
        self.home_text_out.insert("0.0", "Текст после преобразования")

        # create second frame
        self.second_frame = customtkinter.CTkFrame(self, corner_radius=0, fg_color="transparent")

        # create third frame
        self.third_frame = customtkinter.CTkFrame(self, corner_radius=0, fg_color="transparent")

        # select default frame
        self.select_frame_by_name("home")

    def select_frame_by_name(self, name):
        # set button color for selected button
        self.home_button.configure(fg_color=("gray75", "gray25") if name == "home" else "transparent")
        self.frame_2_button.configure(fg_color=("gray75", "gray25") if name == "frame_2" else "transparent")

        # show selected frame
        if name == "home":
            self.home_frame.grid(row=0, column=1, sticky="nsew")
        else:
            self.home_frame.grid_forget()
        if name == "frame_2":
            self.second_frame.grid(row=0, column=1, sticky="nsew")
        else:
            self.second_frame.grid_forget()

    def button_process_event(self):
        self.home_text_out.delete("0.0", "end-1c")
        self.home_text_out.insert("0.0", f"{self.home_text_in.get("0.0", "end-1c")} - после преобразования")

    def home_button_event(self):
        self.select_frame_by_name("home")

    def frame_2_button_event(self):
        self.select_frame_by_name("frame_2")


    def change_appearance_mode_event(self, new_appearance_mode):
        customtkinter.set_appearance_mode(new_appearance_mode)


if __name__ == "__main__":
    app = App()
    app.mainloop()