NAME
im_quantim, im_quantlut, im_spatres - quantise an image or a lut
SYNOPSIS
#include <vips/vips.h>
int im_quantim(in, out, no_of_bits)
IMAGE *in, *out;
int no_of_bits;
int im_quantlut(lut, no_of_bits)
IMAGE *lut;
int no_of_bits;
int im_spatres(in, out, step)
IMAGE *in, *out;
int step;
DESCRIPTION
im_quantim() quantises the image file held by in using no_of_bits and
writes the result to out. The no_of_bits should be between 1 and 7
inclusive. Input can have any number of bands. The function expects
as input a valid unsigned char image.
These functions are here for compatibility only. You should use the
boolean operations im_andconst(3), im_orconst(3), im_shrink(3),
im_zoom(3) and im_lowpass(3).
im_quantlut() creates an one band unsigned char lookup table which is
used by im_quantim(3). The no_of_bits should be between 1 and 7
inclusive.
im_spatres() reduces the spatial resolution of in by averaging
step*step pixels and replicating the result in out. The function can
be used in order to show the effect of reducing the spatial resolution
of a given image and the importance of post-filtering before
displaying. Input can have any number of bands.
RETURN VALUE
All functions returns 0 on success and -1 on error.
SEE ALSO
im_andconst(3), im_orconst(3), im_shrink(3), im_zoom(3) im_lowpass(3).
COPYRIGHT
N. Dessipris
AUTHOR
N. Dessipris - 10/05/1991
10 May 1991