/* dECMC.c
 *
 * Modified:
 * 31/10/12
 * 	- from dE76.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

 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif /*HAVE_CONFIG_H*/
#include <vips/intl.h>

#include <vips/vips.h>
#include <vips/debug.h>

#include "pcolour.h"

typedef struct _VipsdECMC {
	VipsColourDifference parent_instance;

} VipsdECMC;

typedef VipsColourSpaceClass VipsdECMCClass;

G_DEFINE_TYPE( VipsdECMC, vips_dECMC, VIPS_TYPE_COLOUR_DIFFERENCE );

static void
vips_dECMC_class_init( VipsdECMCClass *class )
{
	VipsObjectClass *object_class = (VipsObjectClass *) class;
	VipsColourClass *colour_class = VIPS_COLOUR_CLASS( class );

	object_class->nickname = "dECMC";
	object_class->description = _( "calculate dECMC" );

	colour_class->process_line = vips__pythagoras_line;
}

static void
vips_dECMC_init( VipsdECMC *dECMC )
{
	VipsColourDifference *difference = VIPS_COLOUR_DIFFERENCE( dECMC ); 

	difference->interpretation = VIPS_INTERPRETATION_CMC;
}

/**
 * vips_dECMC:
 * @left: first input image
 * @right: second input image
 * @out: output image
 *
 * Calculate dE CMC. The input images are transformed to CMC colour space and
 * the euclidean distance between corresponding pixels calculated. 
 *
 * To calculate a colour difference with values for (l:c) other than (1:1),
 * transform the two source images to CMC yourself, scale the channels
 * appropriately, and call this function.
 *
 * See also: vips_colourspace()
 *
 * Returns: 0 on success, -1 on error
 */
int
vips_dECMC( VipsImage *left, VipsImage *right, VipsImage **out, ... )
{
	va_list ap;
	int result;

	va_start( ap, out );
	result = vips_call_split( "dECMC", ap, left, right, out );
	va_end( ap );

	return( result );
}
