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
/local/homes/rhaschke/nst7/man/../o.linx86//../nstsrc/nst_contour.c