/*
 * Brute force align the bands of an image.
 *
 * Copyright: Nottingham Trent University
 * Author: Tom Vajzovic
 * Written on: 2008-02-04
 */

/*

	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., 51 Franklin Street, Fifth Floor, Boston, MA
	02110-1301  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 <glib/gi18n-lib.h>
#include <vips/vips.h>
#include <vips/vips7compat.h>

/**
 * im_align_bands:
 * @in: image to align
 * @out: output image
 *
 * This operation uses im_phasecor_fft() to find an integer displacement to
 * align all image bands band 0. It is very slow and not very accurate.
 *
 * Use im_estpar() in preference: it's fast and accurate.
 *
 * See also: im_global_balancef(), im_remosaic().
 *
 * Returns: 0 on success, -1 on error
 */
int
im_align_bands(IMAGE *in, IMAGE *out)
{
#define FUNCTION_NAME "im_align_bands"
	if (im_piocheck(in, out))
		return -1;

	if (1 == in->Bands)
		return im_copy(in, out);
	{
		IMAGE **bands = IM_ARRAY(out, 2 * in->Bands, IMAGE *);
		IMAGE **wrapped_bands = bands + in->Bands;
		double x = 0.0;
		double y = 0.0;
		int i;

		if (!bands ||
			im_open_local_array(out, bands, in->Bands,
				FUNCTION_NAME ": bands", "p") ||
			im_open_local_array(out, wrapped_bands + 1, in->Bands - 1,
				FUNCTION_NAME ": wrapped_bands", "p"))
			return -1;

		for (i = 0; i < in->Bands; ++i)
			if (im_extract_band(in, bands[i], i))
				return -1;

		wrapped_bands[0] = bands[0];

		for (i = 1; i < in->Bands; ++i) {
			IMAGE *temp = im_open(FUNCTION_NAME ": temp", "t");
			double this_x, this_y, val;

			if (!temp ||
				im_phasecor_fft(bands[i - 1], bands[i], temp) ||
				im_maxpos_avg(temp, &this_x, &this_y, &val) ||
				im_close(temp))
				return -1;

			x += this_x;
			y += this_y;

			if (im_wrap(bands[i], wrapped_bands[i], (int) x, (int) y))
				return -1;
		}
		return im_gbandjoin(wrapped_bands, out, in->Bands);
	}
#undef FUNCTION_NAME
}
