#    nnbimg -- Return the value of the nearest neighbor pixel
# 
#    Description:
#    ------------
#    This module returns the value of the nearest neighbor pixel in the
#    input data window, given an x and y co-ordinate in the reference
#    frame of the input file. These co-ordinates should be in pixels.
#    This version handles both cases (with, without mask) assuming the
#    input has been "squished".
#
#        Version    Date        Author     Description
#                27-JAN-1993  RAY WILLIAMSON Convert to SPP
#           3    30-AUG-1983  PAT MURPHY   Generalize code
#           2     5-AUG-1983  PAT MURPHY   Add PDL and FORTRAN code
#           1     5-AUG-1983  PAT MURPHY   Prolog Generation

procedure nnbimg ( xcoord, ycoord, input, dim1,dim2, badpix, result)

int dim1, dim2                          #  The size of the input image
int i,j                                 #  Local temporary variables
real input[dim1,dim2]                   #  The input image
real xcoord, ycoord                     #  The location in the input image
real badpix, result                     #  Fill value and the result

begin

	#  Assume point is outside window
        result = badpix

	#  Get nearest integers to coordinate
        i = int (.5 + xcoord)
        j = int (.5 + ycoord)

	#       Check if the requested point is within the data window

        if (i > 0 && j > 0 && i <= dim1 && j <= dim2) {
	    result = input[i,j]
	}

end