/* 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>

 */

#include "config.h"

#include <glib/gi18n-lib.h>

#ifdef GEGL_CHANT_PROPERTIES

gegl_chant_double (radius, _("Radius"), 0.0, 200.0, 4.0,

  _("Radius of square pixel region (width and height will be radius*2+1)"))

#else

#define GEGL_CHANT_TYPE_AREA_FILTER

#define GEGL_CHANT_C_FILE       "box-min.c"

#include "gegl-chant.h"

#include <stdio.h>

#include <math.h>

static inline gfloat

get_min_component (gfloat *buf,

                   gint    buf_width,

                   gint    buf_height,

                   gint    x0,

                   gint    y0,

                   gint    width,

                   gint    height,

                   gint    component)

{

  gint    x, y;

  gfloat min=1000000000.0;

  gint    count=0;

  gint offset = (y0 * buf_width + x0) * 4 + component;

  for (y=y0; y

    {

    for (x=x0; x

      {

        if (x>=0 && x

            y>=0 && y

          {

            if (buf [offset] < min)

              min = buf[offset];

            count++;

          }

        offset+=4;

      }

      offset+= (buf_width * 4) - 4 * width;

    }

   return min;

}

static void

hor_min (GeglBuffer          *src,

         const GeglRectangle *src_rect,

         GeglBuffer          *dst,

         const GeglRectangle *dst_rect,

         gint                 radius)

{

  gint u,v;

  gint offset;

  gfloat *src_buf;

  gfloat *dst_buf;

  src_buf = g_new0 (gfloat, src_rect->width * src_rect->height * 4);

  dst_buf = g_new0 (gfloat, dst_rect->width * dst_rect->height * 4);

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

                   GEGL_AUTO_ROWSTRIDE, GEGL_ABYSS_NONE);

  offset = 0;

  for (v=0; v<dst_rect->height; v++)

    for (u=0; u<dst_rect->width; u++)

      {

        gint i;

        for (i=0; i<4; i++)

          dst_buf [offset++] = get_min_component (src_buf,

                               src_rect->width,

                               src_rect->height,

                               u + radius - radius,

                               v + radius,

                               1 + radius*2,

                               1,

                               i);

      }

  gegl_buffer_set (dst, dst_rect, 0, babl_format ("RGBA float"), dst_buf,

                   GEGL_AUTO_ROWSTRIDE);

  g_free (src_buf);

  g_free (dst_buf);

}

static void

ver_min (GeglBuffer *src,

         const GeglRectangle *src_rect,

         GeglBuffer          *dst,

         const GeglRectangle *dst_rect,

         gint                 radius)

{

  gint u,v;

  gint offset;

  gfloat *src_buf;

  gfloat *dst_buf;

  src_buf = g_new0 (gfloat, src_rect->width * src_rect->height * 4);

  dst_buf = g_new0 (gfloat, dst_rect->width * src_rect->height * 4);

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

                   GEGL_AUTO_ROWSTRIDE, GEGL_ABYSS_NONE);

  offset=0;

  for (v=0; v<dst_rect->height; v++)

    for (u=0; u<dst_rect->width; u++)

      {

        gint c;

        for (c=0; c<4; c++)

          dst_buf [offset++] =

           get_min_component (src_buf,

                              src_rect->width,

                              src_rect->height,

                              u,

                              v - radius,

                              1,

                              1 + radius * 2,

                              c);

      }

  gegl_buffer_set (dst, dst_rect, 0, babl_format ("RGBA float"), dst_buf,

                   GEGL_AUTO_ROWSTRIDE);

  g_free (src_buf);

  g_free (dst_buf);

}

static void prepare (GeglOperation *operation)

{

  GeglOperationAreaFilter *area = GEGL_OPERATION_AREA_FILTER (operation);

  area->left  =

  area->right =

  area->top   =

  area->bottom = GEGL_CHANT_PROPERTIES (operation)->radius;

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

}

static gboolean

process (GeglOperation       *operation,

         GeglBuffer          *input,

         GeglBuffer          *output,

         const GeglRectangle *result,

         gint                 level)

{

  GeglChantO *o = GEGL_CHANT_PROPERTIES (operation);

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

  hor_min ( input, &input_rect, output, result, o->radius);

  ver_min (output,      result, output, result, o->radius);

  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:box-min",

  "categories"  , "misc",

  "description" ,

        _("Sets the target pixel to the value of the minimum value in a box surrounding the pixel"),

        NULL);

}

#endif