NCL Website header
NCL Home > Documentation > HLUs > API

NhlNDCPolymarker

The Fortran name of this function is NhlFNDCPolymarker.

Given arrays containing the X and Y coordinates of points in NDC space, this function outputs an immediate-mode marker at each of the points.


C Synopsis

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

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

Fortran Synopsis

      subroutine NhlFNDCPolymarker(pid, gsid, x, y, n, ierr)
      integer pid, gsid, n, ierr
      float 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 NDC space.
y (input)
Array of Y-Axis coordinate values in NDC 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

This function draws an immediate-mode polymarker (a set of glyphs marking particular locations) in NDC space. If the parameter pid specifies a transform (a plot object) the polymarker is clipped to the object's viewport. If the parameter pid specifies a workstation, the polymarker is clipped only at the boundaries of the NDC viewspace. An immediate-mode polymarker 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 polymarker's attributes by passing in a GraphicStyle object using the parameter gsid. If gsid is set to NhlNULLOBJID (0) then the marker 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 NhlNDCPolymarker C function returns a value of type NhlErrorTypes, and the NhlFNDCPolymarker 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


See Also