/* count lines

 *

 * Copyright: 1990, N. Dessipris.

 *

 * Author: Nicos Dessipris

 * Written on: 02/05/1990

 * Modified on :

 *

 * 19/9/95 JC

 *  - tidied up

 * 23/10/10

 *  - gtk-doc

 * 17/1/14

 *  - redone as a class, now just a convenience function

 */

/*

  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 <vips/vips.h>

#include <vips/internal.h>

#include <vips/debug.h>

#include "pmorphology.h"

typedef struct _VipsCountlines {

  VipsMorphology parent_instance;

  double nolines;

  VipsDirection direction;

} VipsCountlines;

typedef VipsMorphologyClass VipsCountlinesClass;

G_DEFINE_TYPE(VipsCountlines, vips_countlines, VIPS_TYPE_MORPHOLOGY);

static int

vips_countlines_build(VipsObject *object)

{

  VipsMorphology *morphology = VIPS_MORPHOLOGY(object);

  VipsCountlines *countlines = (VipsCountlines *) object;

  VipsImage *in = morphology->in;

  VipsImage **t = (VipsImage **) vips_object_local_array(object, 7);

  double nolines;

  if (VIPS_OBJECT_CLASS(vips_countlines_parent_class)->build(object))

    return -1;

  /* Compiler warnings.

   */

  nolines = 1;

  switch (countlines->direction) {

  case VIPS_DIRECTION_HORIZONTAL:

    if (!(t[0] = vips_image_new_matrixv(1, 2, -1.0, 1.0)) ||

      vips_moreeq_const1(in, &t[1], 128, NULL) ||

      vips_conv(t[1], &t[2], t[0],

        "precision", VIPS_PRECISION_INTEGER,

        NULL) ||

      vips_project(t[2], &t[3], &t[4], NULL) ||

      vips_avg(t[3], &nolines, NULL))

      return -1;

    break;

  case VIPS_DIRECTION_VERTICAL:

    if (!(t[0] = vips_image_new_matrixv(2, 1, -1.0, 1.0)) ||

      vips_moreeq_const1(in, &t[1], 128, NULL) ||

      vips_conv(t[1], &t[2], t[0],

        "precision", VIPS_PRECISION_INTEGER,

        NULL) ||

      vips_project(t[2], &t[3], &t[4], NULL) ||

      vips_avg(t[4], &nolines, NULL))

      return -1;

    break;

  default:

    g_assert_not_reached();

  }

  g_object_set(object, "nolines", nolines / 255.0, NULL);

  return 0;

}

static void

vips_countlines_class_init(VipsCountlinesClass *class)

{

  GObjectClass *gobject_class = G_OBJECT_CLASS(class);

  VipsObjectClass *vobject_class = VIPS_OBJECT_CLASS(class);

  VIPS_DEBUG_MSG("vips_countlines_class_init\n");

  gobject_class->set_property = vips_object_set_property;

  gobject_class->get_property = vips_object_get_property;

  vobject_class->nickname = "countlines";

  vobject_class->description = _("count lines in an image");

  vobject_class->build = vips_countlines_build;

  VIPS_ARG_DOUBLE(class, "nolines", 2,

    _("Nolines"),

    _("Number of lines"),

    VIPS_ARGUMENT_REQUIRED_OUTPUT,

    G_STRUCT_OFFSET(VipsCountlines, nolines),

    0, 10000000, 0.0);

  VIPS_ARG_ENUM(class, "direction", 3,

    _("Direction"),

    _("Countlines left-right or up-down"),

    VIPS_ARGUMENT_REQUIRED_INPUT,

    G_STRUCT_OFFSET(VipsCountlines, direction),

    VIPS_TYPE_DIRECTION, VIPS_DIRECTION_HORIZONTAL);

}

static void

vips_countlines_init(VipsCountlines *countlines)

{

}

/**

 * vips_countlines: (method)

 * @in: input image

 * @nolines: (out): output average number of lines

 * @direction: count lines horizontally or vertically

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

 *

 * Function which calculates the number of transitions

 * between black and white for the horizontal or the vertical

 * direction of an image.  black<128 , white>=128

 * The function calculates the number of transitions for all

 * Xsize or Ysize and returns the mean of the result

 * Input should be one band, 8-bit.

 *

 * ::: seealso

 *     [method@Image.morph], [method@Image.conv].

 *

 * Returns: 0 on success, -1 on error.

 */

int

vips_countlines(VipsImage *in, double *nolines,

  VipsDirection direction, ...)

{

  va_list ap;

  int result;

  va_start(ap, direction);

  result = vips_call_split("countlines", ap, in, nolines, direction);

  va_end(ap);

  return result;

}