NAME
im_grad_x, im_grad_y - find horizontal or vertical differences
SYNOPSIS
#include <vips/vips.h>
int im_grad_x( IMAGE *in, IMAGE *out );
int im_grad_y( IMAGE *in, IMAGE *out );
DESCRIPTION
im_grad_x(3) generates an image where the value of each pixel is the
difference between horizontally ajacent pixels in the input image. The
output has the same height as the input and one pixel less width.
im_grad_y(3) generates an image where the value of each pixel is the
difference between vertically ajacent pixels in the input image. The
output has the same width as the input and one pixel less height.
In both cases, the input can be any uncoded integer type, and the
output is signed 32 bit integer.
RETURN VALUE
The functions returns 0 on success and -1 on error.
COPYRIGHT
Copyright 2008, Nottingham Trent University.
AUTHOR
Tom Vajzovic
08 January 2008 IM_GRAD_X(3)