PLOTIF - A line-drawing routine, described in terms of "pen moves". Most calls to PLOTIF specify whether

       To  use PLOTIF or c_plotif, 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_plotif (float fx, float fy, int ip)

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

UNIX                                               March 1993                                     PLOTIF(3NCARG)

       FX          (an  input  expression of type REAL) is the X fractional coordinate of the point to which the
                   plotter pen is to be moved.  If IP = 2, this argument is ignored.

       FY          (an input expression of type REAL) is the Y fractional coordinate of the point to  which  the
                   plotter pen is to be moved.  If IP = 2, this argument is ignored.

       IP          (an  input  expression of type INTEGER) determines whether the movement of the plotter pen to
                   the point (FX,FY) will occur with the pen up (IP = 0), or with the pen down (IP = 1).  If  IP
                   = 2, no pen move occurs, but the SPPS polyline buffer is flushed.

       Use the ncargex command to see the following relevant examples: arex01, cbex01, cmppos,  coex03,  cpexcc,
       epltch.

       PLOTIF - A line-drawing routine, described in terms of "pen moves".  Most calls to PLOTIF specify whether
       the "pen" should be up (not drawing) or down (drawing) and then move it to a designated position in the
       fractional coordinate system.  The polylines resulting from the pen moves are buffered; some calls to
       PLOTIF just cause the SPPS polyline buffer to be flushed.

       Online: gpl, plotit, setusv, getusv, sflush, frstpt, vector, line, curve, spps, spps_params, ncarg_cbind

       Hardcopy: NCAR Graphics Fundamentals, UNIX Version; User's Guide for NCAR GKS-0A Graphics

       CALL PLOTIF (FX,FY,IP)

       "CALL PLOTIF (FX,FY,0)" moves the pen to a new starting position.

       "CALL  PLOTIF  (FX,FY,1)"  moves  the  pen  to  a  new position, drawing a straight line segment from the
       previous position to the new one.

       "CALL PLOTIF (0.,0.,2)" flushes the SPPS polyline buffer.

       The size of the SPPS polyline buffer can be changed by calling the parameter-setting  routine  SETUSV  to
       set the parameter 'PB'.  The legal range of 'PB' is between 2 and 50.  For example, to set 'PB' to 2, use
       "CALL SETUSV ('PB',2)".

       NOTE!

       The  SPPS  polyline  buffer  is provided to increase drawing efficiency.  However, there are side effects
       that can occur because the polyline segments get buffered.  For example, if  one  wanted  to  change  the
       color  of a line at a certain point, one would have to remember to flush the buffer before calling GSPLCI
       to change the polyline color index.  This applies to the changing of any polyline attribute.