from PIL import Image

def grayscale( original ) :
    ''' produce a grayscale pixels to their monochrome luminances, using NTSC
        formula mapping (r, g, b) to (m, m, m), where m = .299r + .587g + .114b '''

    # get image dimensions
    ow, oh = original.size          # get the dimensions of the original
    nw, nh = ow, oh                 # new image has same dimensions

    # create new image 
    new = Image.new( 'RGB', (nw, nh ) )

    # consider every pixel
    for nx in range( 0, nw ) :          # consider every possible x value
        for ny in range( 0, nh ) :      # consider every possible y value
            # get coordinates of interest
            ncoord = ( nx, ny )
            ocoord = ( nx, ny )

            # get color of the original pixel

            # determine monochrome luminance of that pixel

            # set new image pixel color 

    # return the result
    return new


if ( __name__ == '__main__' ) :

    # class person of interest
    import url

    # web image of interest
    reply = input( 'Enter web picture location: ' )
    link = reply.strip()

    im1 = url.get_web_image( link )
    im1.show()

    gray1 = grayscale( im1 )
    gray1.show()

    reply = input( 'Enter id: ' )
    who = reply.strip()

    im2 = url.get_student_image( who )
    im2.show()

    gray2 = grayscale( im2 )
    gray2.show()