# negative.py, by chaynes@indiana.edu

import image

def negative_image(matrix):
    """Return a new matrix that is the negative image of the given matrix."""
    answer = []
    for i in range(len(matrix)):
        row = []
        answer.append(row)
        for j in range(len(matrix[0])):
            pixel = matrix[i][j]
            new_pixel = negative_pixel(pixel)
            row.append(new_pixel)
    return answer

def negative_pixel(pixel):
    red = pixel[0]
    green = pixel[1]
    blue = pixel[2]
    return (255 - red, 255 - green, 255 - blue)

def main():
    """Show a negative image of the  bonsai picture."""
    m = image.read('bonsai.jpg')
    image.new(m).show()
    im = image.new(negative_image(m))
    im.show()

if __name__ == '__main__':
    main()