void cvFloodFill(CvArr* image,
                 CvPoint seed_point,
                 CvScalar new_val,
                 CvScalar lo_diff = cvScalarAll(0),
                 CvScalar up_diff=cvScalarAll(0),
                 CvConnectedComp* comp=NULL,
                 int flags=4,
                 CvArr* mask=NULL)