lvarviff(3)

LIBRARY ROUTINE
lvarviff - Extracts a single data value from a viff structure for the cantata parser.

LIBRARY CALL
#include "vinclude.h"
int
lvarviff(image,x,y,band,value)
struct xvimage *image;
int     x,y,band;
double  *value;

INPUT

image
    xvimage structure

x   value location in x direction (column index)

y   value location in y direction (row index)

band
    band number of value

    Note that indexing begins at zero (0).

OUTPUT

value
    single data element of pixel value.

Return Value:
    1 on success, 0 on failure.

MODIFICATIONS

DESCRIPTION
lvarviff takes as input a viff data structure and extracts a single data value (image pixel or vector element) based upon the user indicated location (X, Y, and band number). The extracted data value is returned to the calling routine. When lvarviff is used with varviff(1), the data extracted can be referenced in any valid Cantata expression.

Note that band and location numbering begins at zero (0).

SEE ALSO
varviff(1), intro(3), vipl(3), verror(3), vutils(3)

RESTRICTIONS
lvarviff currently only extreacts single values from a file. It does not extract information from the viff header or from color map or location data. varviff Does not work on data types: VFF_TYP_BIT, VFF_TYP_COMPLEX.

AUTHOR
John Rasure and Carla Williams

COPYRIGHT
Copyright 1991, University of New Mexico. All rights reserved.