Pythonで作る！Tkinter画像ビューア＆簡易編集アプリ完全解説 (App002)

import tkinter as tk
from tkinter import filedialog, ttk, messagebox
from tkinterdnd2 import DND_FILES, TkinterDnD
from PIL import Image, ImageTk, ImageEnhance
import os
import glob


class ImageViewer:
    def __init__(self, root):
        self.root = root
        self.root.title("画像ビューア")
        self.root.geometry("900x650")
        self.root.configure(bg="white")

        # 現在の状態
        self.current_image = None
        self.display_image = None
        self.image_path = None
        self.image_list = []

        # Undo/Redo（画像＋スライダー値）
        self.undo_stack = []
        self.redo_stack = []

        # パラメータ
        self.angle_var = tk.DoubleVar(value=0)
        self.brightness_var = tk.DoubleVar(value=1.0)
        self.contrast_var = tk.DoubleVar(value=1.0)

        self.build_menu()
        self.build_ui()

        # ドラッグ＆ドロップ
        self.root.drop_target_register(DND_FILES)
        self.root.dnd_bind("<<Drop>>", self.drop_files)

    # ======================================================
    # メニューバー
    # ======================================================
    def build_menu(self):
        menubar = tk.Menu(self.root)

        filemenu = tk.Menu(menubar, tearoff=0)
        filemenu.add_command(label="開く", command=self.open_file)
        filemenu.add_command(label="保存", command=self.save_image)
        filemenu.add_separator()
        filemenu.add_command(label="終了", command=self.root.quit)
        menubar.add_cascade(label="ファイル", menu=filemenu)

        self.root.config(menu=menubar)

    # ======================================================
    # UI構築
    # ======================================================
    def build_ui(self):
        # 画像表示
        self.canvas = tk.Label(self.root, bg="white")
        self.canvas.pack(fill=tk.BOTH, expand=True)

        ctrl = tk.Frame(self.root, bg="white")
        ctrl.pack(fill=tk.X, pady=5)

        ttk.Button(ctrl, text="前へ", command=self.prev_image).pack(side=tk.LEFT, padx=5)
        ttk.Button(ctrl, text="次へ", command=self.next_image).pack(side=tk.LEFT, padx=5)

        ttk.Button(ctrl, text="縮小", command=lambda: self.scale_image(0.8)).pack(side=tk.LEFT, padx=10)
        ttk.Button(ctrl, text="拡大", command=lambda: self.scale_image(1.2)).pack(side=tk.LEFT, padx=10)
        ttk.Button(ctrl, text="グレースケール", command=self.to_gray).pack(side=tk.LEFT, padx=10)

        # Undo/Redo
        ttk.Button(ctrl, text="Undo", command=self.undo).pack(side=tk.RIGHT, padx=10)
        ttk.Button(ctrl, text="Redo", command=self.redo).pack(side=tk.RIGHT, padx=10)

        # 角度
        rotate_frame = tk.Frame(self.root, bg="white")
        rotate_frame.pack(fill=tk.X)
        tk.Label(rotate_frame, text="角度", bg="white").pack(side=tk.LEFT)
        tk.Scale(rotate_frame, variable=self.angle_var, from_=-180, to=180,
                 orient="horizontal", command=self.rotate_image).pack(fill=tk.X, padx=10)

        # 明るさ
        bright_frame = tk.Frame(self.root, bg="white")
        bright_frame.pack(fill=tk.X)
        tk.Label(bright_frame, text="明るさ", bg="white").pack(side=tk.LEFT)
        tk.Scale(bright_frame, variable=self.brightness_var, from_=0.1, to=2.0,
                 resolution=0.1, orient="horizontal",
                 command=self.update_brightness).pack(fill=tk.X, padx=10)

        # コントラスト
        contrast_frame = tk.Frame(self.root, bg="white")
        contrast_frame.pack(fill=tk.X)
        tk.Label(contrast_frame, text="コントラスト", bg="white").pack(side=tk.LEFT)
        tk.Scale(contrast_frame, variable=self.contrast_var, from_=0.1, to=2.0,
                 resolution=0.1, orient="horizontal",
                 command=self.update_contrast).pack(fill=tk.X, padx=10)

    # ======================================================
    # D&D
    # ======================================================
    def drop_files(self, event):
        path = event.data.strip("{}")
        path = os.path.abspath(path)
        self.load_image(path)
        self.make_file_list(path)

    # ======================================================
    # ファイルを開く
    # ======================================================
    def open_file(self):
        path = filedialog.askopenfilename(
            filetypes=[("画像ファイル", "*.png;*.jpg;*.jpeg;*.bmp")]
        )
        if path:
            path = os.path.abspath(path)
            self.load_image(path)
            self.make_file_list(path)

    # ======================================================
    # 同じフォルダの画像一覧
    # ======================================================
    def make_file_list(self, path):
        folder = os.path.dirname(os.path.abspath(path))
        exts = ("*.png", "*.jpg", "*.jpeg", "*.bmp")
        files = []
        for e in exts:
            files.extend(glob.glob(os.path.join(folder, e)))
        self.image_list = sorted(os.path.abspath(f) for f in files)

    # ======================================================
    # 保存
    # ======================================================
    def save_image(self):
        if self.display_image is None:
            return
        path = filedialog.asksaveasfilename(
            defaultextension=".png",
            filetypes=[("PNG", "*.png"), ("JPEG", "*.jpg"), ("BMP", "*.bmp")]
        )
        if path:
            self.display_image.save(path)
            messagebox.showinfo("保存", "保存しました。")

    # ======================================================
    # 前へ / 次へ
    # ======================================================
    def prev_image(self):
        if not self.image_list:
            return
        idx = self.image_list.index(self.image_path)
        idx = (idx - 1) % len(self.image_list)
        self.load_image(self.image_list[idx])

    def next_image(self):
        if not self.image_list:
            return
        idx = self.image_list.index(self.image_path)
        idx = (idx + 1) % len(self.image_list)
        self.load_image(self.image_list[idx])

    # ======================================================
    # Undo / Redo（画像 + スライダー値保存）
    # ======================================================
    def push_undo(self):
        if self.display_image is not None:
            state = {
                "image": self.display_image.copy(),
                "angle": self.angle_var.get(),
                "brightness": self.brightness_var.get(),
                "contrast": self.contrast_var.get(),
            }
            self.undo_stack.append(state)
            self.redo_stack.clear()

    def undo(self):
        if not self.undo_stack:
            return

        # 今の状態を redo へ
        cur_state = {
            "image": self.display_image.copy(),
            "angle": self.angle_var.get(),
            "brightness": self.brightness_var.get(),
            "contrast": self.contrast_var.get(),
        }
        self.redo_stack.append(cur_state)

        # 復元
        state = self.undo_stack.pop()
        self.display_image = state["image"]
        self.angle_var.set(state["angle"])
        self.brightness_var.set(state["brightness"])
        self.contrast_var.set(state["contrast"])
        self.show_image()

    def redo(self):
        if not self.redo_stack:
            return

        # 今の状態を undo へ
        cur_state = {
            "image": self.display_image.copy(),
            "angle": self.angle_var.get(),
            "brightness": self.brightness_var.get(),
            "contrast": self.contrast_var.get(),
        }
        self.undo_stack.append(cur_state)

        # 復元
        state = self.redo_stack.pop()
        self.display_image = state["image"]
        self.angle_var.set(state["angle"])
        self.brightness_var.set(state["brightness"])
        self.contrast_var.set(state["contrast"])
        self.show_image()

    # ======================================================
    # 画像読み込み
    # ======================================================
    def load_image(self, path):
        path = os.path.abspath(path)
        self.image_path = path
        self.current_image = Image.open(path)
        self.display_image = self.current_image.copy()

        # Undo/Redo 初期化
        self.undo_stack.clear()
        self.redo_stack.clear()

        # スライダー初期化
        self.angle_var.set(0)
        self.brightness_var.set(1.0)
        self.contrast_var.set(1.0)

        self.show_image()

    # ======================================================
    # 表示処理
    # ======================================================
    def show_image(self):
        if self.display_image is None:
            return
        img = self.display_image.copy()

        # 表示領域に収める
        w, h = img.size
        max_w, max_h = 850, 550
        r = min(max_w / w, max_h / h, 1)
        img = img.resize((int(w * r), int(h * r)))

        self.tk_img = ImageTk.PhotoImage(img)
        self.canvas.config(image=self.tk_img)

    # ======================================================
    # 編集機能
    # ======================================================
    def scale_image(self, rate):
        if self.display_image:
            self.push_undo()
            w, h = self.display_image.size
            self.display_image = self.display_image.resize((int(w * rate), int(h * rate)))
            self.show_image()

    def to_gray(self):
        if self.display_image:
            self.push_undo()
            self.display_image = self.display_image.convert("L").convert("RGB")
            self.show_image()

    def rotate_image(self, event=None):
        if self.current_image:
            self.push_undo()
            angle = self.angle_var.get()
            self.display_image = self.current_image.rotate(-angle, expand=True)
            self.show_image()

    def update_brightness(self, event=None):
        if self.current_image:
            self.push_undo()
            enhancer = ImageEnhance.Brightness(self.current_image)
            self.display_image = enhancer.enhance(self.brightness_var.get())
            self.show_image()

    def update_contrast(self, event=None):
        if self.current_image:
            self.push_undo()
            enhancer = ImageEnhance.Contrast(self.current_image)
            self.display_image = enhancer.enhance(self.contrast_var.get())
            self.show_image()


# ======================================================
# メイン
# ======================================================
root = TkinterDnD.Tk()
app = ImageViewer(root)
root.mainloop()