/* 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 2006 Øyvind Kolås <pippin@gimp.org>

 * Copyright 2008 Bradley Broom <bmbroom@gmail.com>

 */

#include "config.h"

#include <glib/gi18n-lib.h>

#ifdef GEGL_CHANT_PROPERTIES

gegl_chant_int (pattern, _("Bayer pattern"), 0, 3, 0,

                _("Bayer pattern used, 0 seems to work for some nikon files, 2 for some Fuji files."))

#else

#define GEGL_CHANT_TYPE_AREA_FILTER

#define GEGL_CHANT_C_FILE       "demosaic-bimedian.c"

#include "gegl-chant.h"

/* Returns the median of four floats. We define the median as the average of

 * the central two elements.

 */

static inline gfloat

m4 (gfloat a, gfloat b, gfloat c, gfloat d)

{

  gfloat t;

  /* Sort ab */

  if (a > b)

    {

      t = b;

      b = a;

      a = t;

    }

  /* Sort abc */

  if (b > c)

    {

      t = c;

      c = b;

      if (a > t)

        {

          b = a;

          a = t;

        }

      else

    b = t;

    }

  /* Return average of central two elements. */

  if (d >= c) /* Sorted order would be abcd */

    return (b + c) / 2.0;

  else if (d >= a) /* Sorted order would be either abdc or adbc */

    return (b + d) / 2.0;

  else /* Sorted order would be dabc */

    return (a + b) / 2.0;

}

/* Defines to make the row/col offsets below obvious. */

#define ROW src_rect->width

#define COL 1

/* We expect src_extent to have a one pixel border around all four sides

 * of dst_extent.

 */

static void

demosaic (GeglChantO          *op,

          GeglBuffer          *src,

          const GeglRectangle *src_rect,

          GeglBuffer          *dst,

          const GeglRectangle *dst_rect)

{

  gint x,y;

  gint offset, doffset;

  gfloat *src_buf;

  gfloat *dst_buf;

  src_buf = g_new0 (gfloat, src_rect->width * src_rect->height * 1);

  dst_buf = g_new0 (gfloat, dst_rect->width * dst_rect->height * 3);

  gegl_buffer_get (src, src_rect, 1.0, babl_format ("Y float"), src_buf,

                   GEGL_AUTO_ROWSTRIDE, GEGL_ABYSS_NONE);

  offset = ROW + COL;

  doffset = 0;

  for (y=dst_rect->y; y<dst_rect->height + dst_rect->y; y++)

    {

      for (x=dst_rect->x; x<dst_rect->width + dst_rect->x; x++)

        {

          gfloat red=0.0;

          gfloat green=0.0;

          gfloat blue=0.0;

          if ((y + op->pattern%2)%2==0)

            {

              if ((x+op->pattern/2)%2==1)

                {

                  /* GRG

                   * BGB

                   * GRG

                   */

                  blue =(src_buf[offset-COL]+src_buf[offset+COL])/2.0;

                  green=src_buf[offset];

                  red  =(src_buf[offset-ROW]+src_buf[offset+ROW])/2.0;

                }

              else

                {

                  /* RGR

                   * GBG

                   * RGR

                   */

                  blue =src_buf[offset];

                  green=m4(src_buf[offset-ROW], src_buf[offset-COL],

                           src_buf[offset+COL], src_buf[offset+ROW]);

                  red  =m4(src_buf[offset-ROW-COL], src_buf[offset-ROW+COL],

                           src_buf[offset+ROW-COL], src_buf[offset+ROW+COL]);

                }

            }

          else

            {

              if ((x+op->pattern/2)%2==1)

                {

                  /* BGB

                   * GRG

                   * BGB

                   */

                  blue =m4(src_buf[offset-ROW-COL], src_buf[offset-ROW+COL],

                       src_buf[offset+ROW-COL], src_buf[offset+ROW+COL]);

                  green=m4(src_buf[offset-ROW], src_buf[offset-COL],

                       src_buf[offset+COL], src_buf[offset+ROW]);

                  red  =src_buf[offset];

                }

              else

                {

                  /* GBG

                   * RGR

                   * GBG

                   */

                  blue =(src_buf[offset-ROW]+src_buf[offset+ROW])/2.0;

                  green=src_buf[offset];

                  red  =(src_buf[offset-COL]+src_buf[offset+COL])/2.0;

                }

            }

          dst_buf [doffset*3+0] = red;

          dst_buf [doffset*3+1] = green;

          dst_buf [doffset*3+2] = blue;

          offset++;

          doffset++;

        }

      offset+=2;

    }

  gegl_buffer_set (dst, dst_rect, 0, babl_format ("RGB float"), dst_buf, GEGL_AUTO_ROWSTRIDE);

  g_free (src_buf);

  g_free (dst_buf);

}

/* Specify required extra pixels around dst_extent: one pixel on every side.

 */

static void prepare (GeglOperation *operation)

{

  GeglOperationAreaFilter *area = GEGL_OPERATION_AREA_FILTER (operation);

  area->right = area->bottom = 1;

  area->left  = area->top    = 1;

  gegl_operation_set_format (operation, "output", babl_format ("RGB float"));

}

static gboolean

process (GeglOperation       *operation,

         GeglBuffer          *input,

         GeglBuffer          *output,

         const GeglRectangle *result,

         gint                 level)

{

  GeglChantO *o = GEGL_CHANT_PROPERTIES (operation);

  GeglRectangle src_rect = gegl_operation_get_required_for_output (operation, "input", result);

  demosaic (o, input, &src_rect, output, result);

  return  TRUE;

}

static void

gegl_chant_class_init (GeglChantClass *klass)

{

  GeglOperationClass       *operation_class;

  GeglOperationFilterClass *filter_class;

  operation_class = GEGL_OPERATION_CLASS (klass);

  filter_class    = GEGL_OPERATION_FILTER_CLASS (klass);

  filter_class->process    = process;

  operation_class->prepare = prepare;

  gegl_operation_class_set_keys (operation_class,

    "name"        , "gegl:demosaic-bimedian",

    "categories"  , "blur",

    "description" ,

          _("Performs a grayscale2color demosaicing of an image, using bimedian interpolation."),

          NULL);

}

#endif