Question

PYTHON3

Write a program to apply a 'negative' filter on a greyscale image. The program should ask the user to enter a filename, open this file, perform the transformation (as described below) and then save the negative version of the image to the file 'output.png'.

To perform the negative effect, set each pixel in the output image to the opposite colour value than the corresponding pixel in the input image. For example, a colour value of 0 would become 255, 1 would become 254, 253 would become 2, and so on.

Here is an example of the effect your program should produce: astronaut.png Enter a filename: astronaut.png output.png

Answer 1

Hii, I have answered a previous version of this question before. Here is the completed code for this problem. Comments are included, go through it, learn how things work and let me know if you have any doubts or if you need anything to change. If you are satisfied with the solution, please rate the answer. Thanks

#code

from PIL import Image


# method to convert a grayscale image into its negative
def convertNegative(img):
    # loading pixels of img
    pixels = img.load()
    # getting width and heght
    width = img.size[0]
    height = img.size[1]
    #looping through each column and row
    for i in range(width):
        for j in range(height):
            #changing pixel color to opposite
            pixels[i,j]=255-pixels[i,j]
    #returning modified image
    return img


#getting filename
inputFileName=input('Enter a filename: ')
#opening image in grayscale mode
img=Image.open(inputFileName).convert('L')

#converting to negative
convertNegative(img)
#saving as output.png
img.save('output.png')

#output

Enter a filename: gray.png

#gray.png

#output.png