im_zone(3)

NAME

im_zone, im_fzone - creates a zone plate

SYNOPSIS

#include <vips/vips.h>
int im_zone(image, size)
IMAGE *image;
int size;
int im_fzone(image, size)
IMAGE *image;
int size;

DESCRIPTION

im_fzone() creates a float one band image of a zone plate of size size by size. Pels are in the range [-1,+1]. The zone plate has spatial frequencies increasing from 0 the center (at size/2, size/2) up to infinity at the edges. size must be positive and even.

im_zone() behaves exactly as im_fzone(), but writes a FMTUCHAR image scaled to the range 0-255.

RETURN VALUE

The function returns 0 on success and -1 on error.

SEE ALSO

im_grey(3), im_fgrey(3).

COPYRIGHT

N. Dessipris

AUTHOR

N. Dessipris - 10/05/1991

10 May 1991 IM_ZONE(3)