/* make a test pattern to show the eye's frequency response

 *

 * Copyright: 1990, 1991, N.Dessipris.

 *

 * Author N. Dessipris

 * Written on 30/05/1990

 * Updated on: 27/01/1991, 07/03/1991,

 * 22/7/93 JC

 *  - im_outcheck() added

 * 30/8/95 JC

 *  - modernized

 * 1/2/11

 *  - gtk-doc

 * 13/6/13

 *  - redo 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

 */

/*

#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"

typedef struct _VipsEye {

  VipsPoint parent_instance;

  double factor;

} VipsEye;

typedef VipsPointClass VipsEyeClass;

G_DEFINE_TYPE(VipsEye, vips_eye, VIPS_TYPE_POINT);

static float

vips_eye_point(VipsPoint *point, int x, int y)

{

  VipsEye *eye = (VipsEye *) point;

  /* VIPS_MAX to prevent /0.

   */

  int max_x = VIPS_MAX(point->width - 1, 1);

  int max_y = VIPS_MAX(point->height - 1, 1);

  double c = eye->factor * VIPS_PI / (2 * max_x);

  double h = max_y * max_y;

  return y * y * cos(c * x * x) / h;

}

static void

vips_eye_class_init(VipsEyeClass *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 = "eye";

  vobject_class->description =

    _("make an image showing the eye's spatial response");

  point_class->point = vips_eye_point;

  VIPS_ARG_DOUBLE(class, "factor", 6,

    _("Factor"),

    _("Maximum spatial frequency"),

    VIPS_ARGUMENT_OPTIONAL_INPUT,

    G_STRUCT_OFFSET(VipsEye, factor),

    0.0, 1.0, 0.5);

}

static void

vips_eye_init(VipsEye *eye)

{

  eye->factor = 0.5;

}

/**

 * vips_eye:

 * @out: (out): output image

 * @width: image size

 * @height: image size

 * @...: %NULL-terminated list of optional named arguments

 *

 * Optional arguments:

 *

 * * @factor: %gdouble, maximum spatial frequency

 * * @uchar: %gboolean, output a uchar image

 *

 * Create a test pattern with increasing spatial frequency in X and

 * amplitude in Y. @factor should be between 0 and 1 and determines the

 * maximum spatial frequency.

 *

 * Set @uchar to output a uchar image.

 *

 * See also: vips_zone().

 *

 * Returns: 0 on success, -1 on error

 */

int

vips_eye(VipsImage **out, int width, int height, ...)

{

  va_list ap;

  int result;

  va_start(ap, height);

  result = vips_call_split("eye", ap, out, width, height);

  va_end(ap);

  return result;

}