/* This file is an image processing operation for GEGL

 *

 * GEGL 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 3 of the License, or (at your option) any later version.

 *

 * GEGL 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 GEGL; if not, see <http://www.gnu.org/licenses/>.

 *

 * Copyright 2007 Mark Probst <mark.probst@gmail.com>

 */

#include "config.h"

#include <glib/gi18n-lib.h>

#ifdef GEGL_CHANT_PROPERTIES

gegl_chant_int (sampling_points, _("Sample points"), 0, 65536, 0,

                _("Number of curve sampling points.  0 for exact calculation."))

gegl_chant_curve (curve, _("Curve"), _("The contrast curve."))

#else

#define GEGL_CHANT_TYPE_POINT_FILTER

#define GEGL_CHANT_C_FILE  "contrast-curve.c"

#include "gegl-chant.h"

static void prepare (GeglOperation *operation)

{

  const Babl *format = babl_format ("YA float");

  gegl_operation_set_format (operation, "input", format);

  gegl_operation_set_format (operation, "output", format);

}

static gboolean

process (GeglOperation       *op,

         void                *in_buf,

         void                *out_buf,

         glong                samples,

         const GeglRectangle *roi,

         gint                 level)

{

  GeglChantO *o = GEGL_CHANT_PROPERTIES (op);

  gint        num_sampling_points;

  GeglCurve  *curve;

  gint i;

  gfloat  *in  = in_buf;

  gfloat  *out = out_buf;

  gdouble *xs, *ys;

  num_sampling_points = o->sampling_points;

  curve = o->curve;

  if (num_sampling_points > 0)

  {

    xs = g_new(gdouble, num_sampling_points);

    ys = g_new(gdouble, num_sampling_points);

    gegl_curve_calc_values(o->curve, 0.0, 1.0, num_sampling_points, xs, ys);

    g_free(xs);

    for (i=0; i

    {

      gint x = in[0] * num_sampling_points;

      gfloat y;

      if (x < 0)

       y = ys[0];

      else if (x >= num_sampling_points)

       y = ys[num_sampling_points - 1];

      else

       y = ys[x];

      out[0] = y;

      out[1]=in[1];

      in += 2;

      out+= 2;

    }

    g_free(ys);

  }

  else

    for (i=0; i

    {

      gfloat u = in[0];

      out[0] = gegl_curve_calc_value(curve, u);

      out[1]=in[1];

      in += 2;

      out+= 2;

    }

  return TRUE;

}

static void

gegl_chant_class_init (GeglChantClass *klass)

{

  GeglOperationClass            *operation_class;

  GeglOperationPointFilterClass *point_filter_class;

  operation_class    = GEGL_OPERATION_CLASS (klass);

  point_filter_class = GEGL_OPERATION_POINT_FILTER_CLASS (klass);

  point_filter_class->process = process;

  operation_class->prepare = prepare;

  gegl_operation_class_set_keys (operation_class,

    "name"       , "gegl:contrast-curve",

    "categories" , "color",

    "description",

        _("Adjusts the contrast of the image according to a curve."),

        NULL);

}

#endif