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#
# The Python Imaging Library
# $Id: thresholder.py 2134 2004-10-06 08:55:20Z fredrik $
#
# this demo script illustrates how a 1-bit BitmapImage can be used
# as a dynamically updated overlay
#
from Tkinter import *
import Image, ImageTk
import sys
#
# an image viewer
class UI(Frame):
def __init__(self, master, im, value = 128):
Frame.__init__(self, master)
self.image = im
self.value = value
self.canvas = Canvas(self, width=im.size[0], height=im.size[1])
self.backdrop = ImageTk.PhotoImage(im)
self.canvas.create_image(0, 0, image=self.backdrop, anchor=NW)
self.canvas.pack()
scale = Scale(self, orient=HORIZONTAL, from_=0, to=255,
resolution=1, command=self.update, length=256)
scale.set(value)
scale.bind("<ButtonRelease-1>", self.redraw)
scale.pack()
# uncomment the following line for instant feedback (might
# be too slow on some platforms)
# self.redraw()
def update(self, value):
self.value = eval(value)
self.redraw()
def redraw(self, event = None):
# create overlay (note the explicit conversion to mode "1")
im = self.image.point(lambda v,t=self.value: v>=t, "1")
self.overlay = ImageTk.BitmapImage(im, foreground="green")
# update canvas
self.canvas.delete("overlay")
self.canvas.create_image(0, 0, image=self.overlay, anchor=NW,
tags="overlay")
# --------------------------------------------------------------------
# main
root = Tk()
im = Image.open(sys.argv[1])
if im.mode != "L":
im = im.convert("L")
# im.thumbnail((320,200))
UI(root, im).pack()
root.mainloop()
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