libvips/libsrc/mosaicing/im_avgdxdy.c

86 lines
2.1 KiB
C

/* @(#) Function which averages the difference x_secondary[] - x_reference[]
* @(#) and y_secondary[] - y_reference[] of the structure points;
* @(#) The rounded integer result is returnd into dx, dy
* @(#) No IMAGES are involved in this function.
* @(#)
* @(#) int im_avgdxdy( points, dx, dy )
* @(#) TIE_POINTS *points;
* @(#) int *dx, *dy;
* @(#)
* @(#) Returns 0 on sucess and -1 on error.
*
* Copyright: 1990, N. Dessipris.
*
* Author: Nicos Dessipris
* Written on: 20/12/1990
* Modified on : 18/04/1991
*/
/*
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 <math.h>
#include <vips/vips.h>
#include "mosaic.h"
#ifdef WITH_DMALLOC
#include <dmalloc.h>
#endif /*WITH_DMALLOC*/
int
im__avgdxdy( TIE_POINTS *points, int *dx, int *dy )
{
int sumdx, sumdy;
int i;
if( points->nopoints == 0 ) {
im_errormsg( "im_avgdxdy: no points to average" );
return( -1 );
}
/* Lots of points.
*/
sumdx = 0;
sumdy = 0;
for( i = 0; i < points->nopoints; i++ ) {
sumdx += points->x_secondary[i] - points->x_reference[i];
sumdy += points->y_secondary[i] - points->y_reference[i];
}
*dx = IM_RINT( (double) sumdx / (double) points->nopoints );
*dy = IM_RINT( (double) sumdy / (double) points->nopoints );
return( 0 );
}