''' Purpose: support image black and white transformation
'''

def size( original ) :
    ''' Purpose: return the size of the new image when performing a
            black and white transformation
    '''

    nw, nh = original.size

    return (nw, nh)

def color( opixel ) :
    ''' Purpose: return the new pixel when performing a black and white
            transformation of opixel
    '''

    # How do I make opixel so that it is EITHER black or white?
    r,g,b = opixel # THIS IS IMPORTANT. We want to extract the r,g,b from the original pixel
                   # and use the r,g,b of the original pixel to get the new color you want based
                   # on the r,g,b values.
    # We want to check if the color is a lighter color or a darker color:
    rgb_sum = r + g + b
    rgb_average = rgb_sum // 3
    if ( rgb_average < ( 255 // 2 ) ):  # If opixel is a darker color
        npixel = (0,0,0) # (0,0,0) is the tuple for black
    else:  # If opixel is a lighter color
        npixel = (255,255,255) # (255,255,255) is the tuple for white
    return npixel

def where( nspot, original = None ) :
    ''' Purpose: return the correspondent of nspot in the original when
            doing a black and white transformation
    '''

    ospot = nspot

    return ospot

if ( __name__ == '__main__' ) :

    import url
    from manip import manip
    
    # get web image of interest
    link = "http://www.cs.virginia.edu/~cs1112/images/mandrill/full.png"

    original = url.get_image( link )

    original.show()

    new_image = manip( original, size, color, where )

    new_image.show()