/* 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>

#include <stdlib.h>

#ifdef GEGL_CHANT_PROPERTIES

gegl_chant_int_ui   (x,        _("Width"),  1, G_MAXINT, 16, 1, 256, 1.5,

                  _("Horizontal width of cells pixels"))

gegl_chant_int_ui   (y,        _("Height"), 1, G_MAXINT, 16, 1, 256, 1.5,

                  _("Vertical width of cells in pixels"))

gegl_chant_int_ui   (x_offset, _("X offset"), -G_MAXINT, G_MAXINT, 0, -10, 10, 1.0,

                  _("Horizontal offset (from origin) for start of grid"))

gegl_chant_int_ui   (y_offset, _("Y offset"), -G_MAXINT, G_MAXINT,  0, -10, 10, 1.0,

                  _("Vertical offset (from origin) for start of grid"))

gegl_chant_color (color1,   _("Color"), "black",

                  _("One of the cell colors (defaults to 'black')"))

gegl_chant_color (color2,   _("Other color"), "white",

                  _("The other cell color (defaults to 'white')"))

#else

#define GEGL_CHANT_TYPE_POINT_RENDER

#define GEGL_CHANT_C_FILE       "checkerboard.c"

#include "gegl-chant.h"

static void

prepare (GeglOperation *operation)

{

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

}

static GeglRectangle

get_bounding_box (GeglOperation *operation)

{

  return gegl_rectangle_infinite_plane ();

}

static gboolean

process (GeglOperation       *operation,

         void                *out_buf,

         glong                n_pixels,

         const GeglRectangle *roi,

         gint                 level)

{

  GeglChantO *o = GEGL_CHANT_PROPERTIES (operation);

  gfloat     *out_pixel = out_buf;

  gfloat      color1[4];

  gfloat      color2[4];

  gint        x = roi->x; /* initial x                   */

  gint        y = roi->y; /*           and y coordinates */

  gegl_color_get_pixel (o->color1, babl_format ("RGBA float"), color1);

  gegl_color_get_pixel (o->color2, babl_format ("RGBA float"), color2);

  while (n_pixels--)

    {

      gint nx,ny;

      if ((x - o->x_offset) < 0)

        {

          nx = div (x - o->x_offset + 1, o->x).quot;

        }

      else

        {

          nx = div (x - o->x_offset, o->x).quot;

        }

      if ((y - o->y_offset) < 0)

        {

          ny = div (y - o->y_offset + 1, o->y).quot;

        }

      else

        {

          ny = div (y - o->y_offset, o->y).quot;

        }

      /* shift negative cell indices */

      nx -= (x - o->x_offset) < 0 ? 1 : 0;

      ny -= (y - o->y_offset) < 0 ? 1 : 0;

      if ( (nx+ny) % 2 == 0)

        {

          out_pixel[0]=color1[0];

          out_pixel[1]=color1[1];

          out_pixel[2]=color1[2];

          out_pixel[3]=color1[3];

        }

      else

        {

          out_pixel[0]=color2[0];

          out_pixel[1]=color2[1];

          out_pixel[2]=color2[2];

          out_pixel[3]=color2[3];

        }

      out_pixel += 4;

      /* update x and y coordinates */

      x++;

      if (x>=roi->x + roi->width)

        {

          x=roi->x;

          y++;

        }

    }

  return  TRUE;

}

static void

gegl_chant_class_init (GeglChantClass *klass)

{

  GeglOperationClass            *operation_class;

  GeglOperationPointRenderClass *point_render_class;

  operation_class = GEGL_OPERATION_CLASS (klass);

  point_render_class = GEGL_OPERATION_POINT_RENDER_CLASS (klass);

  point_render_class->process = process;

  operation_class->get_bounding_box = get_bounding_box;

  operation_class->prepare = prepare;

  gegl_operation_class_set_keys (operation_class,

    "name",  "gegl:checkerboard",

    "categories", "render",

    "description", _("Checkerboard renderer"),

    NULL);

}

#endif