Schematically:
FuncNgbOp2dExtra2Dispatch  -->  _Row(P1,Cnum)  -->  _Pix_P1Cnum
                             |
                             |
                             +->  _Row(P1,Loop)  -->  _Pix_P1Loop
                             |                    /
                             +->  _Row(P2,Loop)  -->  _Pix_P2Loop
                             |
                             +->  _Row(PN,Loop)  -->  _Pix_P1Loop
 1.5.1