#!python
# -*- mode: python; Encoding: utf-8; coding: utf-8 -*-
# Last updated: <2022/04/08 05:05:46 +0900>
"""
Canvas scale sample.

* Windows10 x64 21H2 + Python 3.9.12 64bit + Pillow 9.1.0
* Windows10 x64 21H2 + Python 2.7.18 32bit + Pillow 6.2.2
"""

try:
    # Python 3.x
    import tkinter as tk
except Exception:
    # Python 2.7
    import Tkinter as tk

from PIL import Image, ImageTk


class App(tk.Frame, object):
    """My App."""

    def __init__(self, master=None):
        tk.Frame.__init__(self, master)

        self.master.title("Canvas sample")
        self.master.geometry("600x600")

        self.frm = tk.Frame(self.master)
        self.frm.pack(expand=1, fill=tk.BOTH)
        self.frm.rowconfigure(1, weight=1)
        self.frm.columnconfigure(0, weight=1)

        # create Button, Label
        self.bfrm = tk.Frame(self.frm)
        self.bfrm.grid(row=0, column=0, sticky=tk.W + tk.E)

        self.btn0 = tk.Button(self.bfrm, text="-", command=lambda: self.dec_ratio())
        self.btn1 = tk.Button(self.bfrm, text="+", command=lambda: self.inc_ratio())
        self.lblstr = tk.StringVar()
        self.lblstr.set("100%")
        self.lbl = tk.Label(self.bfrm, textvariable=self.lblstr)
        self.btn0.pack(side=tk.LEFT, ipadx=8, padx=4)
        self.btn1.pack(side=tk.LEFT, ipadx=8, padx=4)
        self.lbl.pack(side=tk.LEFT, ipadx=8, padx=8)

        # create Canvas
        self.canvas = tk.Canvas(self.frm, bg="#666666")
        self.canvas.grid(row=1, column=0, sticky=tk.N + tk.S + tk.W + tk.E)

        # load image
        self.im = Image.open("lena_std.png")
        self.photo_image = ImageTk.PhotoImage(image=self.im)

        self.now_ratio = 1.0
        self.tgt_ratio = 1.0

        self.update()
        cw = self.canvas.winfo_width()
        ch = self.canvas.winfo_height()

        # draw image
        self.canvas.create_image(cw / 2, ch / 2, image=self.photo_image)

        # darw Rectangle, Oval, Polygon
        x = cw / 2
        y = ch / 2
        self.canvas.create_rectangle(x, y, x + 24, y + 96, width=4, outline="#ff0000")
        self.canvas.create_oval(x + 32, y + 32, x - 32, y - 32, width=6, outline="#00ff00")
        self.canvas.create_polygon(x, y, x - 40, y - 60, x - 80, y + 30,
                                   width=2, outline="#0000ff", fill="")

    def inc_ratio(self):
        self.tgt_ratio = self.tgt_ratio + 0.5
        self.tgt_ratio = min([12.0, self.tgt_ratio])
        self.lblstr.set("%d%%" % int(self.tgt_ratio * 100))
        self.scale_canvas()

    def dec_ratio(self):
        self.tgt_ratio = self.tgt_ratio - 0.5
        self.tgt_ratio = max([0.5, self.tgt_ratio])
        self.lblstr.set("%d%%" % int(self.tgt_ratio * 100))
        self.scale_canvas()

    def scale_canvas(self):
        v = self.tgt_ratio / self.now_ratio
        cw = self.canvas.winfo_width()
        ch = self.canvas.winfo_height()
        self.canvas.scale(tk.ALL, cw / 2, ch / 2, v, v)
        self.now_ratio = self.now_ratio * v


def main():
    root = tk.Tk()
    app = App(master=root)
    app.mainloop()


if __name__ == '__main__':
    main()