NAME

iso_contour -- render iso-contour

PROTOTYPE

unitptr iso_contour( int iOperands, int iDx, int iDy, int iLevels, float fXmin, float fXmax, float fYmin, float fYmax, char *pcWindow, char *pcOptions, unitptr uHost)

ARGUMENTS

int iOperands
nr of operand units or 0
int iDx
nr of isodata points along x axis
int iDy
nr of isodata points along y axis
int iLevels
nr of levels to draw
float fXmin
initial value for x min value
float fXmax
initial value for x max value
float fYmin
initial value for y min value
float fYmax
initial value for y max value
char *pcWindow
window to use (name or offset)
char *pcOptions
options. %Xc sets color as X=0..7
unitptr uHost
host unit

RETURN VALUE:

A pointer to the created unit or NULL in the case of an error.

INTERFACE OF CREATED UNIT:

X_in[iDx*iDy]:
(packed input field 0) the isodata
Y_in[iLevels]:
the level values
Z_in[iLevels]:
(input field 1) a color index for each level value.
in_3[4]:
scaling parameters Xmin, Xmax, Ymin, Ymax
CTL_in[]:
(control field)

SYNOPSIS:

Computes and optionally renders an isocontour for a volume data set of iDx x iDy scalar values on a 2-dimensional orthogonal grid. The isocontour will belong to the isovalue specified at input field Y_in. The data at input field X_in[] specify the data, the data at input field Z_in[] specify how the isocontour will be colored (see OPTIONS below). The computed isocontour will be a polygon line. If iOperands==0, the unit will render the isocontour. If iOperands!=0, the unit will act as an iterator over all segments of the isocontour, executing its abs(iOperands) successor units for each segment while offering the vertices of the current segment at the two output fields X_out[2] and Y_out[2]. A third output field will hold a normal vector for the current segment with length normalized to the length of the current segment. This mode allows to perform special computations on the isocontour, such as flow or surface calculation. When in iterator mode, the sign of iOperands chooses whether additional rendering occurs (for iOperands>0) or whether rendering is disabled (for iOperands<0, if only some computation on the surface is desired).

OPTIONS:

The option string pcOpt allows to specify options. Currently only the option %Xc is supported to set the default color of all isocontours to value X (can be overridden by specifying colors at input field 2).

EXAMPLES:

STATUS:

Alpha.

SEE ALSO:

iso_surface

FILE

/amnt/loge/users/nistaff02/nistaff/rhaschke/nst7/man/../o.linux//../nstsrc/nst_contour.c