CPCHCL - Called by the Conpack routines CPCLDM and CPCLDR. The default version does nothing. A user-

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

       Copyright (C) 1987-2009
       University Corporation for Atmospheric Research

       The use of this Software is governed by a License Agreement.

UNIX                                               March 1993                                     CPCHCL(3NCARG)

       IFLG        (INTEGER, input) is +1 if a line is about to be drawn, -1 if a line has just been drawn.

       CPCHCL - Called by the Conpack routines CPCLDM and CPCLDR.  The default version does nothing.  A user-
       written version may be supplied to provide control as contour lines are drawn.

       Online:  conpack, cpback, cpchcf, cpchhl, cpchil, cpchll, cpcica, cpclam, cpcldm, cpcldr, cpcltr, cpcnrc,
       cpdrpl, cpezct, cpgetc, cpgeti, cpgetr, cplbam, cplbdr, cpmpxy, cpmviw, cpmvrw, cppkcl,  cppklb,  cprect,
       cprset, cpscae, cpsetc, cpseti, cpsetr, cpsps1, cpsps2, ncarg_cbind

       CALL CPCHCL (IFLG)

       The  routine  CPCHCL  is  not  to  be called by the user. It is called by the Conpack routines CPCLDM and
       CPCLDR just before and just after the contour lines at each level  are  drawn.  The  default  version  of
       CPCHCL  does  nothing. A user-supplied replacement may change attributes such as color and line width (by
       calling the SPPS routine SETUSV or the appropriate GKS routines).

       If the element of the parameter array 'CLU' corresponding to 'PAI' = -1 has been set non-zero to  request
       the drawing of the edge of the grid, then CPCHCL will be called before and after that is done. Similarly,
       if  the  element  of  'CLU' corresponding to 'PAI' = -2 has been set non-zero, then CPCHCL will be called
       before and after the drawing of the edges of the special-value  areas,  and,  if  the  element  of  'CLU'
       corresponding  to  'PAI'  =  -3  has  been  set non-zero, then CPCHCL will be called before and after the
       drawing of the edges of the out-of-range areas.

       When CPCHCL is called, the parameter 'PAI' will have been set to the index  of  the  appropriate  contour
       level  (between  1  and  'NCL')  or to one of the values -1, -2, or -3. By retrieving the value of 'PAI',
       CPCHCL can find out what line is being drawn; also, a CPGETx call to retrieve an element of  a  parameter
       array like 'CLD' will automatically get the correct one for the line being drawn.