TDLNPA - Given the coordinates of two points in the reference parallelogram, draw the projection of the

       To  use TDLNPA or c_tdlnpa, load the NCAR Graphics libraries ncarg, ncarg_gks, and ncarg_c, preferably in
       that order.

       The C-binding argument descriptions are the same as the FORTRAN argument descriptions.

       #include <ncarg/ncargC.h>

       void c_tdlnpa(float xcp1, float ycp1, float xcp2, float ycp2)

       Copyright (C) 1987-2009
       University Corporation for Atmospheric Research
       The use of this Software is governed by a License Agreement.

UNIX                                                July 1997                                     TDLNPA(3NCARG)

       The arguments of TDLNPA are as follows:

       XCP1 and YCP1
               (input  expressions  of  type  REAL)  - the parallelogram coordinates of a point in the reference
               parallelogram (as defined by the last call to TDPARA).

       XCP2 and YCP2
               (input expressions of type REAL)  -  the  parallelogram  coordinates  of  another  point  in  the
               reference parallelogram.

       TDLNPA - Given the coordinates of two points in the reference parallelogram, draw the projection of the
       line joining them.

       Online: tdclrs, tdctri, tddtri, tdgeti, tdgetr, tdgrds, tdgrid, tdgtrs, tdinit, tditri,  tdlbla,  tdlbls,
       tdline,  tdmtri,  tdotri,  tdpack, tdpack_params, tdpara, tdplch, tdprpa, tdprpi, tdprpt, tdseti, tdsetr,
       tdsort, tdstri, tdstrs

       CALL TDLNPA (XCP1, YCP1, XCP2, YCP2)