libvips/libsrc/histograms_lut/im_heq.c

80 lines
2.0 KiB
C

/* @(#) Histogram equalises the input uchar image; result in uchar
* @(#) If bandno=0 all bands are equilised independantly
* @(#) else input image is equilised using the histogram of bandno only.
* @(#) Image descriptors should have been set properly by the calling program
* @(#)
* @(#) Usage: heq imagein imageout bandno
* @(#) int im_heq(in, out, bandno)
* @(#) IMAGE *in, *out;
* @(#) int bandno;
* @(#)
* @(#) Returns 0 on sucess and -1 on error
* @(#)
*
* Copyright: 1991, N. Dessipris.
*
* Author: Nicos Dessipris
* Written on: 27/03/1991
* Modified on :
* 16/6/93 J.Cupitt
* - im_ioflag() changed to im_iocheck()
* 24/5/95 JC
* - ANSIfied and tidied up
* 3/3/01 JC
* - more cleanup
*/
/*
This file is part of VIPS.
VIPS is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
/*
These files are distributed with VIPS - http://www.vips.ecs.soton.ac.uk
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif /*HAVE_CONFIG_H*/
#include <vips/intl.h>
#include <stdio.h>
#include <vips/vips.h>
#ifdef WITH_DMALLOC
#include <dmalloc.h>
#endif /*WITH_DMALLOC*/
int
im_heq( IMAGE *in, IMAGE *out, int bandno )
{
IMAGE *t1 = im_open_local( out, "im_heq:1", "p" );
IMAGE *t2 = im_open_local( out, "im_heq:2", "p" );
if( !t1 || !t2 ||
im_histgr( in, t1, bandno ) ||
im_histeq( t1, t2 ) ||
im_maplut( in, out, t2 ) )
return( -1 );
return( 0 );
}