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.help cf_calc_range May94 source
.ih
NAME
cf_calc_range -- Calculate starting pixel and length of array.
.endhelp
#---------------------------------------------------------------------------
procedure cf_calc_range (start_pixel, end_pixel, center, size, length,
			 start, range)

int	start_pixel		# I:  Start pixel of range.
int	end_pixel		# I:  End pixel of range.
int	center			# I:  Center pixel of range.
int	size			# I:  Size of range.
int	length			# I:  Total length of array.
int	start			# O:  Start pixel.
int	range			# O:  Number of pixels in range.

int	i			# Generic.

begin
	if (IS_INDEFI(start_pixel) || IS_INDEFI(end_pixel)) {
	    if (IS_INDEFI(center))
		i = length / 2
	    else
		i = center
	    start = i - (size / 2)
	    range = size
	} else {
	    start = start_pixel
	    range = end_pixel - start_pixel + 1
	}

	# Check for consistency on the pixel range.
	if (start < 1 || start+range-1 > length)
	    call error (1, "cf_calc_range: range out of bounds")
end
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# End of cf_calc_range
#---------------------------------------------------------------------------