ncl_plotif (3) - Linux Manuals

ncl_plotif: A line-drawing routine, described in terms of "pen moves".

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.

COPYRIGHT

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