/* Turn XYZ to Yxy colourspace.

 *

 * Modified:

 * 29/5/02 JC

 *  - from lab2xyz

 * 2/11/09

 *  - gtkdoc

 *  - cleanups

 * 20/9/12

 *  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

 */

#ifdef HAVE_CONFIG_H

#include <config.h>

#endif /*HAVE_CONFIG_H*/

#include <glib/gi18n-lib.h>

#include <stdio.h>

#include <math.h>

#include <vips/vips.h>

#include "pcolour.h"

typedef VipsColourTransform VipsXYZ2Yxy;

typedef VipsColourTransformClass VipsXYZ2YxyClass;

G_DEFINE_TYPE(VipsXYZ2Yxy, vips_XYZ2Yxy, VIPS_TYPE_COLOUR_TRANSFORM);

static void

vips_XYZ2Yxy_line(VipsColour *colour, VipsPel *out, VipsPel **in, int width)

{

  float *restrict p = (float *) in[0];

  float *restrict q = (float *) out;

  int i;

  for (i = 0; i < width; i++) {

    float X = p[0];

    float Y = p[1];

    float Z = p[2];

    double total = X + Y + Z;

    float x, y;

    p += 3;

    if (total == 0.0) {

      x = 0;

      y = 0;

    }

    else {

      x = X / total;

      y = Y / total;

    }

    q[0] = Y;

    q[1] = x;

    q[2] = y;

    q += 3;

  }

}

static void

vips_XYZ2Yxy_class_init(VipsXYZ2YxyClass *class)

{

  VipsObjectClass *object_class = (VipsObjectClass *) class;

  VipsColourClass *colour_class = VIPS_COLOUR_CLASS(class);

  object_class->nickname = "XYZ2Yxy";

  object_class->description = _("transform XYZ to Yxy");

  colour_class->process_line = vips_XYZ2Yxy_line;

}

static void

vips_XYZ2Yxy_init(VipsXYZ2Yxy *XYZ2Yxy)

{

  VipsColour *colour = VIPS_COLOUR(XYZ2Yxy);

  colour->interpretation = VIPS_INTERPRETATION_YXY;

}

/**

 * vips_XYZ2Yxy: (method)

 * @in: input image

 * @out: (out): output image

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

 *

 * Turn XYZ to Yxy.

 *

 * Returns: 0 on success, -1 on error

 */

int

vips_XYZ2Yxy(VipsImage *in, VipsImage **out, ...)

{

  va_list ap;

  int result;

  va_start(ap, out);

  result = vips_call_split("XYZ2Yxy", ap, in, out);

  va_end(ap);

  return result;

}