NhlDataPolygon

The Fortran name of this function is NhlFDataPolygon.

Given arrays containing the X and Y coordinates of points in data coordinate space, this function outputs an immediate-mode polygon connecting each of the points.

C Synopsis

#include <ncarg/hlu/hlu.h>
#include <hfile for Transform class object>

NhlErrorTypes NhlDataPolygon(
		int	pid,
                int     gsid,
		float 	*x,
		float	*y,
		int	n,
		)

Fortran Synopsis

      subroutine NhlFDataPolygon(pid, gsid, x, y, n, ierr)
      integer pid, gsid, n, ierr
      real x(n), y(n)

Arguments

pid (input): Id of a Transform or Workstation object.
gsid (input): Id of a GraphicStyle object.
x (input): Array of X-Axis coordinate values in data coordinate space.
y (input): Array of Y-Axis coordinate values in data coordinate space.
n (input): Number of elements in the coordinate arrays x and y.
ierr (output, Fortran only): Error code.

Types

Type name:		NhlTErrorTypes
Definition:
typedef enum _NhlErrType{
	NhlFATAL	= -4,	/* "FATAL"	*/
	NhlWARNING	= -3,	/* "WARNING"	*/
	NhlINFO		= -2,	/* "INFO"	*/
	NhlNOERROR	= -1	/* "NOERROR"	*/
} NhlErrorTypes;

Description

If the parameter pid specifies a transform (a plot object), this function draws an immediate-mode polygon in the object's current data coordinate space. The polygon is clipped to the object's viewport. If the parameter pid specifies a workstation, the polygon is drawn in a data coordinate space that is identical to NDC space with boundaries of (0.0,0.0) at the lower left and (1.0,1.0) at the upper right. Clipping occurs only at the viewspace boundaries. An immediate-mode polygon appears as soon as the low-level point buffer is flushed after the function is called. It is not drawn when the object's Draw method is invoked.

You specify the polygon's attributes by passing in a GraphicStyle object using the parameter gsid. If gsid is set to NhlNULLOBJID (0) then the polygon attributes are determined by the current settings of the Workstation default GraphicStyle object. Retrieve the id of the default GraphicStyle object using the read-only Workstation resource wkDefGraphicStyleId.

Return Values

The NhlDataPolygon C function returns a value of type NhlErrorTypes, and the NhlFDataPolygon Fortran subroutine returns the error in ierr. The following table indicates what the various return Error Values mean:

Value	|			Meaning
--------+-------------------------------------------------
NOERROR	|	function successful
--------+-------------------------------------------------
INFO	|	minor recoverable error
--------+-------------------------------------------------
WARNING	|	recoverable error
--------+-------------------------------------------------
FATAL	|	function failed; continuing the program
	|       may result in core dump

Copyright

Copyright 1987-1999 University Corporation for Atmospheric Research
The use of this Software is governed by a License Agreement.

NCAR Graphics is a registered trademark of the University Corporation for Atmospheric Research.

Reference Manual Control Panel

NG4.1 Home, Index, Examples, Glossary, Feedback, Ref Contents, Ref WhereAmI?

$Revision: 1.8 $ $Date: 1998/08/19 03:11:39 $