.TH IM_SIGN 3 "July 2002"
.SH NAME
im_sign \- find the unit vector in the direction of value
.SH SYNOPSIS
#include <vips/vips.h>

int im_sign( in, out )
.br
IMAGE *in, *out;
.SH DESCRIPTION
.B im_sign(3)
finds the unit vector in the direction of the pixel value. For non-complex
images, it returns a signed char image with values -1, 0, and 1 for negative,
zero and positive pixels. For complex images it returns a
complex normalised to length 1.
.SH RETURN VALUE
The function returns 0 on success and -1 on error.
.SH SEE ALSO
im_abs(3), im_cmulnorm(3), im_c2amph(3)