A Tkinter viewer for named PIL Images

tk_viewer_simple.py

#!/usr/bin/env python3

''' A Tkinter viewer for named PIL Images

    Image windows can be iconified / deiconified individually via buttons
    in the main viewer window, or iconified / deiconified en masse by
    iconifying / deiconifying the main viewer window.

    Written by PM 2Ring 2017.07.16
'''

from time import sleep
from PIL import Image, ImageTk
import tkinter as tk

class Viewer(tk.Tk):
    ''' View named PIL Images in separate Toplevel windows '''
    def __init__(self):
        super().__init__()
        self.title('Viewer')
        tk.Label(self, text='Viewer main window').pack()
        self.winset = set()
        self.bind("<Map>", lambda e: self.all_cb(e, 1))
        self.bind("<Unmap>", lambda e: self.all_cb(e, 0))
        self.update_idletasks()

    # Create an image window
    def show(self, img, title):
        win = tk.Toplevel(self)
        win.title(title)
        self.winset.add(win)
        win.photo = ImageTk.PhotoImage(img)
        tk.Label(win, image=win.photo).pack()
        tk.Label(win, text=title).pack()
        # Add a map / unmap button for this window to the main window
        win.var = tk.IntVar()
        win.var.set(1)
        win.button = tk.Checkbutton(self, text=title, anchor='nw',
            variable=win.var,
            command=lambda w=win: self.win_show_hide(win, win.var.get()))
        win.button.pack(fill=tk.X, expand=tk.TRUE)

        # Intercept map / unmap events so we can keep win.var in sync
        win.bind("<Map>", lambda e, w=win: self.icon_cb(e, w, 1))
        win.bind("<Unmap>", lambda e, w=win: self.icon_cb(e, w, 0))

        # Intercept close events so we can remove the winset entry
        # and the map / unmap button
        win.protocol("WM_DELETE_WINDOW", lambda w=win: self.close(w))

        # Allow Tkinter to add the button to the main window
        self.update_idletasks()
        # In case Tkinter has other stuff to do, like responding to a 
        # close event for another window
        self.update()
        return win

    # Close an image window
    def close(self, win):
        win.button.destroy()
        self.winset.discard(win)
        win.destroy()

    def win_show_hide(self, win, state):
        (win.deiconify if state else win.iconify)()

    # iconify / deiconify all image windows when
    # the main window is iconified / deiconified
    def all_cb(self, event, state):
        if event.widget == self:
            for win in self.winset:
                self.win_show_hide(win, state)

    # Set an image window's var to reflect its current map / unmap state
    def icon_cb(self, event, win, state):
        if event.widget == win:
            win.var.set(state)

# Test
def main():
    # Set up image viewer
    viewer = Viewer()

    #Make a square image that fades diagonally from black to white
    size = 128
    m = 255.0 / (2 * size - 2)
    r = range(size)
    fade = Image.new('L', (size, size), color=None)
    fade.putdata([round(m * (x + y)) for y in r for x in r])
    fade = fade.convert('RGB')

    # Make some shaded color squares
    colors = ('red', 'yellow', 'green', 'cyan', 'blue', 'magenta')
    windows = {}
    for c in colors:
        # Simulate complex image creation that takes a long time
        sleep(0.5)
        img = Image.new('RGB', (size, size), color=c)
        img = Image.blend(img, fade, 0.5)
        win = viewer.show(img, title=c)
        # Save the window by title for future reference
        windows[c] = win

    sleep(2)
    # Iconify a window
    win = windows['yellow']
    win.iconify()
    viewer.update_idletasks()

    sleep(2)
    # Close a window by its title
    win = windows['cyan']
    viewer.close(win)
    viewer.update()

    sleep(2)
    # Deiconify a window
    win = windows['yellow']
    win.deiconify()
    # We don't need `viewer.update_idletasks()` here because it'll
    # get updated when `viewer.mainloop()` gets called.

    # Wait for the main viewer window to be closed. Alternatively,
    # the viewer can be closed by calling `viewer.destroy()`; otherwise
    # it will be automatically destroyed when the program ends.
    print('waiting')
    viewer.mainloop()

if __name__ == '__main__':
    main()