NAME

       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.

SYNOPSIS

       CALL PLOTIF (FX,FY,IP)

C-BINDING SYNOPSIS

       #include <ncarg/ncargC.h>

       void c_plotif (float fx, float fy, int ip)

DESCRIPTION

       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.

C-BINDING DESCRIPTION

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

USAGE

       "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.

EXAMPLES

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

ACCESS

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

SEE ALSO

       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

COPYRIGHT

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