libvips/libsrc/histograms_lut/im_gammacorrect.c

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2007-08-29 18:23:50 +02:00
/* @(#) Gamma-correct uchar image with factor gammafactor.
* @(#)
* @(#) int im_gammacorrect(in, out, exponent)
* @(#) IMAGE *in, *out;
* @(#) double exponent;
* @(#)
* @(#) Returns 0 on sucess and -1 on error
* @(#)
*
*
* Copyright: 1990, N. Dessipris.
*
* Written on: 19/07/1990
* Modified on:
* 19/6/95 JC
* - redone as library function
*/
/*
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_gammacorrect( IMAGE *in, IMAGE *out, double exponent )
{
IMAGE *t1 = im_open_local( out, "im_gammacorrect:#1", "p" );
IMAGE *t2 = im_open_local( out, "im_gammacorrect:#2", "p" );
IMAGE *t3 = im_open_local( out, "im_gammacorrect:#2", "p" );
if( !t1 || !t2 || !t3 )
return( -1 );
if( im_piocheck( in, out ) )
return( -1 );
if( in->BandFmt != IM_BANDFMT_UCHAR ) {
im_errormsg( "im_gammacorrect: uchar images only" );
return( -1 );
}
if( im_identity( t1, 1 ) ||
im_powtra( t1, t2, exponent ) ||
im_scale( t2, t3 ) ||
im_maplut( in, out, t3 ) )
return( -1 );
return( 0 );
}