Question

Define a function named posterize. This function expects an image and a tuple of RGB values as arguments. The function modifies the image like the blackAndWhite function developed in Chapter 7 and shown below, but it uses passed in RGB values instead of black.

def blackAndWhite(image):
    """Converts the argument image to black and white."""
    blackPixel = (0, 0, 0)
    whitePixel = (255, 255, 255)
    for y in range(image.getHeight()):
        for x in range(image.getWidth()):
            (r, g, b) = image.getPixel(x, y)
            average = (r + g + b) // 3
            if average < 128:
                image.setPixel(x, y, blackPixel)
            else:
                image.setPixel(x, y, whitePixel)

An example of the program is shown below:

"""

File: posterize.py

Project 7.5

Defines and tests a function for posterizing images.

"""

from images import Image

""" Write your code here """

def main():

    filename = input("Enter the image file name: ")

    red = int(input("Enter an integer [0..255] for red: "))

    green = int(input("Enter an integer [0..255] for green: "))

    blue = int(input("Enter an integer [0..255] for blue: "))                    

    image = Image(filename)

    posterize(image, (red, green, blue))

    image.draw()

if __name__ == "__main__":

   main()

Answer 1

I hope you are asking for a function , that can explicitly set the RGB values for the input image, (if I am wrong in this statement, post a comment below, I will help based on that)

The required function is :(updated code),

I really want say, l sont the library you are usinh, Image. Intrsad I used teh opensourse project

from PIL import Image 
def posterize(image, rgb_values):
  '''Converts the argument image to the pixels passed'''
  # for y in range(image.height):
  #   for x in range(image.width):
  #     # image.setPixel(x, y, rgb_values) # directly put the required rgb tuple in the current pixel position
  #     image.putpixel((x,y),rgb_values)


  whitePixel = (255, 255, 255)
  for y in range(image.getHeight()):
    for x in range(image.getWidth()):
      (r, g, b) = image.getPixel(x, y)
      average = (r + g + b) // 3
      if average < 128:
        image.setPixel(x, y, rgb_values)
      else:
        image.setPixel(x, y, whitePixel)

  return image

def main():
  # filename = input("Enter the image file name: ")
  # red = int(input("Enter an integer [0..255] for red: "))
  # green = int(input("Enter an integer [0..255] for green: "))
  # blue = int(input("Enter an integer [0..255] for blue: "))    
  filename = 'panda.jpg'
  red = 100
  green = 100
  blue = 100                
  image = Image.open(filename)
  
  posterize(image, (red, green, blue))
  # image.draw()

if __name__ == "__main__":
  main()

Screenshot of the code : ( to understand the indentation)