/* frequency-domain filter an image
 *
 * Author: Nicos Dessipris
 * Written on: 02/05/1990
 * Modified on : 08/03/1991
 * 16/6/93 J.Cupitt
 *	- im_multiply() called, rather than im_cmultim()
 * 27/10/93 JC
 *	- im_clip2*() called, rather than im_any2*()
 * 20/9/95 JC
 *	- rewritten
 * 10/9/98 JC
 *	- frees memory more quickly
 * 4/3/03 JC
 *	- use im_invfftr() to get real back for speedup
 * 3/1/14
 * 	- redone as a class
 */

/*

	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 <stdio.h>
#include <stdlib.h>

#include <vips/vips.h>
#include "pfreqfilt.h"

typedef struct _VipsFreqmult {
	VipsFreqfilt parent_instance;

	VipsImage *mask;
} VipsFreqmult;

typedef VipsFreqfiltClass VipsFreqmultClass;

G_DEFINE_TYPE(VipsFreqmult, vips_freqmult, VIPS_TYPE_FREQFILT);

static int
vips_freqmult_build(VipsObject *object)
{
	VipsFreqfilt *freqfilt = VIPS_FREQFILT(object);
	VipsFreqmult *freqmult = (VipsFreqmult *) object;
	VipsImage **t = (VipsImage **) vips_object_local_array(object, 5);

	VipsImage *in;

	if (VIPS_OBJECT_CLASS(vips_freqmult_parent_class)->build(object))
		return -1;

	in = freqfilt->in;

	if (vips_band_format_iscomplex(in->BandFmt)) {
		if (vips_multiply(in, freqmult->mask, &t[0], NULL) ||
			vips_invfft(t[0], &t[1], "real", TRUE, NULL))
			return -1;

		in = t[1];
	}
	else {
		/* Optimisation: output of vips_invfft() is double, we
		 * will usually cast to char, so rather than keeping a
		 * large double buffer and partial to char from that,
		 * cast to a memory buffer and copy to out from that.
		 *
		 * FIXME does this actually work now we're a class? test
		 * perhaps we need a temporary object
		 */
		t[4] = vips_image_new_memory();

		if (vips_fwfft(in, &t[0], NULL) ||
			vips_multiply(t[0], freqmult->mask, &t[1], NULL) ||
			vips_invfft(t[1], &t[2], "real", TRUE, NULL) ||
			vips_cast(t[2], &t[3], in->BandFmt, NULL) ||
			vips_image_write(t[3], t[4]))
			return -1;

		in = t[4];
	}

	if (vips_image_write(in, freqfilt->out))
		return -1;

	return 0;
}

static void
vips_freqmult_class_init(VipsFreqmultClass *class)
{
	GObjectClass *gobject_class = G_OBJECT_CLASS(class);
	VipsObjectClass *vobject_class = VIPS_OBJECT_CLASS(class);

	gobject_class->set_property = vips_object_set_property;
	gobject_class->get_property = vips_object_get_property;

	vobject_class->nickname = "freqmult";
	vobject_class->description = _("frequency-domain filtering");
	vobject_class->build = vips_freqmult_build;

	VIPS_ARG_IMAGE(class, "mask", 0,
		_("Mask"),
		_("Input mask image"),
		VIPS_ARGUMENT_REQUIRED_INPUT,
		G_STRUCT_OFFSET(VipsFreqmult, mask));
}

static void
vips_freqmult_init(VipsFreqmult *freqmult)
{
}

/**
 * vips_freqmult: (method)
 * @in: input image
 * @mask: mask image
 * @out: (out): output image
 * @...: %NULL-terminated list of optional named arguments
 *
 * Multiply @in by @mask in Fourier space.
 *
 * @in is transformed to Fourier space, multiplied with @mask, then
 * transformed back to real space. If @in is already a complex image, just
 * multiply then inverse transform.
 *
 * See also: vips_invfft(), vips_mask_ideal().
 *
 * Returns: 0 on success, -1 on error.
 */
int
vips_freqmult(VipsImage *in, VipsImage *mask, VipsImage **out, ...)
{
	va_list ap;
	int result;

	va_start(ap, out);
	result = vips_call_split("freqmult", ap, in, mask, out);
	va_end(ap);

	return result;
}
