''' Purpose: support image inverse transformation
'''

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

    nw, nh = original.size

    return (nw, nh)

def color( opixel ) :
    ''' Purpose: return the new pixel when performing an inverse transformation
            of opixel, that is (255 - r, 255 - g, 255 - b), where r, g, and b
            are are the RGB values of opixel
    '''

    ...

def where( nspot, original = None ) :
    ''' Purpose: return the correspondent of nspot in the original when
            performing a inverse 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()