Example 11-5. PP4E\Gui\PIL\pyphoto1.py

"""
############################################################################
PyPhoto 1.1: thumbnail image viewer with resizing and saves.

Supports multiple image directory thumb windows - the initial img dir
is passed in as cmd arg, uses "images" default, or is selected via main
window button; later directories are opened by pressing "D" in image view
or thumbnail windows.

Viewer also scrolls popped-up images that are too large for the screen;
still to do: (1) rearrange thumbnails when window resized, based on current
window size; (2) [DONE] option to resize images to fit current window size?
(3) avoid scrolls if image size is less than window max size: use Label
if imgwide <= scrwide and imghigh <= scrhigh?

New in 1.1: updated to run in Python 3.1 and latest PIL;

New in 1.0: now does a form of (2) above: image is resized to one of the
display's dimensions if clicked, and zoomed in or out in 10% increments
on key presses; generalize me; caveat: seems to lose quality, pixels
after many resizes (this is probably a limitation of PIL)

The following scaler adapted from PIL's thumbnail code is similar to the
screen height scaler here, but only shrinks:
x, y = imgwide, imghigh
if x > scrwide: y = max(y scrwide // x, 1); x = scrwide
if y > scrhigh: x = max(x scrhigh // y, 1); y = scrhigh
############################################################################
"""

import sys, math, os
from tkinter import *
from tkinter.filedialog import SaveAs, Directory

from PIL import Image # PIL Image: also in tkinter
from PIL.ImageTk import PhotoImage # PIL photo widget replacement
from viewer_thumbs import makeThumbs # developed earlier in book

remember last dirs across all windows

saveDialog = SaveAs(title='Save As (filename gives image type)')
openDialog = Directory(title='Select Image Directory To Open')

trace = print # or lambda *x: None
appname = 'PyPhoto 1.1: '

class ScrolledCanvas(Canvas):
"""
a canvas in a container that automatically makes
vertical and horizontal scroll bars for itself
"""
def init(self, container):
Canvas.init(self, container)
self.config(borderwidth=0)

PyPhoto: An Image Viewer and Resizer | 723