/* 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.
 *
 * See also: vips_morph(), vips_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;
}
