/* base class for frequency filter create operations
 *
 * 02/01/14
 * 	- from sines.c
 */

/*

	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

 */

/*
#define VIPS_DEBUG
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif /*HAVE_CONFIG_H*/
#include <glib/gi18n-lib.h>

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

#include <vips/vips.h>

#include "pcreate.h"
#include "point.h"
#include "pmask.h"

G_DEFINE_ABSTRACT_TYPE(VipsMask, vips_mask, VIPS_TYPE_POINT);

static float
vips_mask_point(VipsPoint *point, int x, int y)
{
	VipsMask *mask = VIPS_MASK(point);
	VipsMaskClass *class = VIPS_MASK_GET_CLASS(point);

	/* VIPS_MAX to prevent /0.
	 */
	int half_width = VIPS_MAX(point->width / 2, 1);
	int half_height = VIPS_MAX(point->height / 2, 1);

	double result;

	/* Move centre for an optical transform mask.
	 */
	if (!mask->optical) {
		x = (x + half_width) % point->width;
		y = (y + half_height) % point->height;
	}

	x = x - half_width;
	y = y - half_height;

	if (!mask->nodc &&
		x == 0 &&
		y == 0)
		/* DC component is always 1.
		 */
		result = 1.0;
	else {
		double dx, dy;

		dx = (double) x / half_width;
		dy = (double) y / half_height;

		result = class->point(mask, dx, dy);

		/* Invert filter sense for a highpass filter, or to swap
		 * band-pass for band-reject.
		 */
		if (mask->reject)
			result = 1.0 - result;
	}

	return result;
}

static void
vips_mask_class_init(VipsMaskClass *class)
{
	GObjectClass *gobject_class = G_OBJECT_CLASS(class);
	VipsObjectClass *vobject_class = VIPS_OBJECT_CLASS(class);
	VipsPointClass *point_class = VIPS_POINT_CLASS(class);

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

	vobject_class->nickname = "mask";
	vobject_class->description = _("base class for frequency filters");

	point_class->point = vips_mask_point;
	point_class->min = 0.0;
	point_class->max = 1.0;
	point_class->interpretation = VIPS_INTERPRETATION_FOURIER;

	VIPS_ARG_BOOL(class, "optical", 5,
		_("Optical"),
		_("Rotate quadrants to optical space"),
		VIPS_ARGUMENT_OPTIONAL_INPUT,
		G_STRUCT_OFFSET(VipsMask, optical),
		FALSE);

	VIPS_ARG_BOOL(class, "reject", 5,
		_("Reject"),
		_("Invert the sense of the filter"),
		VIPS_ARGUMENT_OPTIONAL_INPUT,
		G_STRUCT_OFFSET(VipsMask, reject),
		FALSE);

	VIPS_ARG_BOOL(class, "nodc", 5,
		_("Nodc"),
		_("Remove DC component"),
		VIPS_ARGUMENT_OPTIONAL_INPUT,
		G_STRUCT_OFFSET(VipsMask, nodc),
		FALSE);
}

static void
vips_mask_init(VipsMask *mask)
{
}
