How do I get my program to update this tkinter label in my nested loop so that it shows the grayscale process? - python-3.x

Question

So I made a program that converts an image to grayscale. I first used graphics.py from a Zelle's Python Programming An Introduction To Computer Science book. I believe this is based on tkinter. I finished the program using a nested loop to iterate through a .gif picture and grab each individual pixel, replacing it with a grayscale algorithm. I had the change happen in a loop and it gave it an effect that shows the grayscale happening across the window. This was slow but it looked neat, but I realized I wanted to be able to use more file types. I found PIL for Python 3.3 and tkinter, using PIL to open the images, turning them into a tkinter PhotoImage, than displaying them in a tkinter window. Now my program will show the image before being processed and after, I would simply like to see the program update the image in the loop so that it shows the grayscale process. Any help would be great appreciated.
Here is my code:
from PIL import Image, ImageTk
from graphics import GraphWin
import tkinter
window = tkinter.Tk()
window.title('# Grayscale')
def GrayScaleConvertor():
#Opens image, creates window and draws image
picToConvert = 'sea.jpg'
pic = Image.open(picToConvert)
picWidth, picHeight = pic.size
# Treats the image as a 2d array, iterates through changing the
#values of each pixel with the algorithm for gray
tkPic = ImageTk.PhotoImage(pic, master = window)
label1 = tkinter.Label(window, image = tkPic)
rgbList = pic.load() #Get a 2d array of the pixels
for row in range(picWidth):
for column in range(picHeight):
rgb = rgbList[row,column]
r,g,b = rgb # Unpacks the RGB value tuple per pixel
grayAlgorithm1 = (r+g+b) // 3
rgbList[row,column] = (grayAlgorithm1, grayAlgorithm1, grayAlgorithm1)
# Converting to a tkinter PhotoImage
tkPic1 = ImageTk.PhotoImage(pic, master = window)
label2 = tkinter.Label(window, image = tkPic1)
# Draws the images to the window
label1.pack() # The image before grayscale
label2.pack() # The image after being grayscaled
window.mainloop()
GrayScaleConvertor()

Answer 1

You could use after(time, function_name) to call function (for example) every 10ms and change one (or more) pixel.
pseudocode:
tkinter.after(10, change_one_pixel)
def change_one_pixel():
change_next_pixel() # if you change more pixels you get faster animation
create_new_image()
update_label()
if any_pixel_left:
tkinter.after(10, change_one_pixel)
EDIT:
Full working code
#import Tkinter as tk # Python 2.7.x
import tkinter as tk # Python 3.x
from PIL import Image, ImageTk
class GrayScaleConvertor():
def __init__(self):
self.window = tk.Tk()
self.window.title('# Grayscale')
#Opens image, creates window and draws image
picToConvert = 'sea.jpg'
#picToConvert = 'background.jpg'
self.pic = Image.open(picToConvert)
# Treats the image as a 2d array, iterates through changing the
#values of each pixel with the algorithm for gray
self.tkPic1 = ImageTk.PhotoImage(self.pic, master = self.window)
self.label1 = tk.Label(self.window, image = self.tkPic1)
# Converting to a tkinter PhotoImage
self.tkPic2 = ImageTk.PhotoImage(self.pic, master = self.window)
self.label2 = tk.Label(self.window, image = self.tkPic2)
# Draws the images to the window
self.label1.pack() # The image before grayscale
self.label2.pack() # The image after being grayscaled
self.column = 0 # start column
self.step = 10 # number columns in one step
self.window.after(1, self.change_pixel) # 1ms
def run(self):
self.window.mainloop()
def change_pixel(self):
rgbList = self.pic.load() #Get a 2d array of the pixels
picWidth, picHeight = self.pic.size
# not to leave image
if self.column + self.step > picWidth:
self.step = picWidth - self.column
# change columns
for column in range(self.column, self.column+self.step):
for row in range(picHeight):
rgb = rgbList[column,row]
r,g,b = rgb # Unpacks the RGB value tuple per pixel
grayAlgorithm1 = (r+g+b) // 3
rgbList[column,row] = (grayAlgorithm1, grayAlgorithm1, grayAlgorithm1)
# change image in label
if self.tkPic2:
del self.tkPic2
self.tkPic2 = ImageTk.PhotoImage(self.pic, master = self.window)
self.label2.config(image = self.tkPic2)
# move start column
self.column += self.step
# if still are columns - call again
if self.column < picWidth:
print "change image"
self.window.after(1, self.change_pixel)
else:
print "the end"
GrayScaleConvertor().run()