/* This file is part of GEGL.

 * ck

 *

 * This library 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.

 *

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

 *

 * Copyright 2008 Øyvind Kolås <pippin@gimp.org>

 */

#ifndef __GEGL_BUFFER_ITERATOR_H__

#define __GEGL_BUFFER_ITERATOR_H__

#include "gegl-buffer.h"

#define GEGL_BUFFER_MAX_ITERATORS 6

#define GEGL_BUFFER_READ      1

#define GEGL_BUFFER_WRITE     2

#define GEGL_BUFFER_READWRITE (GEGL_BUFFER_READ|GEGL_BUFFER_WRITE)

typedef struct GeglBufferIterator

{

  gint          length;

  gpointer      data[GEGL_BUFFER_MAX_ITERATORS];

  GeglRectangle roi[GEGL_BUFFER_MAX_ITERATORS];

  gint          level;

} GeglBufferIterator;

/**

 * gegl_buffer_iterator_new:

 * @buffer: a #GeglBuffer

 * @roi: the rectangle to iterate over

 * @format: the format we want to process this buffers data in, pass 0 to use the buffers format.

 * @flags: whether we need reading or writing to this buffer one of GEGL_BUFFER_READ, GEGL_BUFFER_WRITE and GEGL_BUFFER_READWRITE.

 * @level: the level at which we are iterating, the roi will indicate the

 * extent at 1:1, x,y,width and height are/(2^level)

 *

 * Create a new buffer iterator, this buffer will be iterated through

 * in linear chunks, some chunks might be full tiles the coordinates, see

 * the documentation of gegl_buffer_iterator_next for how to use it and

 * destroy it.

 *

 * Returns: a new buffer iterator that can be used to iterate through the

 * buffers pixels.

 */

GeglBufferIterator * gegl_buffer_iterator_new  (GeglBuffer          *buffer,

                                                const GeglRectangle *roi,

                                                gint                 level,

                                                const Babl          *format,

                                                guint                flags,

                                                GeglAbyssPolicy      abyss_policy);

/**

 * gegl_buffer_iterator_add:

 * @iterator: a #GeglBufferIterator

 * @buffer: a #GeglBuffer

 * @roi: the rectangle to iterate over

 * @format: the format we want to process this buffers data in, pass 0 to use the buffers format.

 * @flags: whether we need reading or writing to this buffer.

 *

 * Adds an additional buffer iterator that will be processed in sync with

 * the original one, if the buffer doesn't align with the other for tile access

 * the corresponding scans and regions will be serialized automatically using

 * gegl_buffer_get.

 *

 * Returns: an integer handle refering to the indice in the iterator structure

 * of the added buffer.

 */

gint                 gegl_buffer_iterator_add  (GeglBufferIterator  *iterator,

                                                GeglBuffer          *buffer,

                                                const GeglRectangle *roi,

                                                gint                 level,

                                                const Babl          *format,

                                                guint                flags,

                                                GeglAbyssPolicy      abyss_policy);

/**

 * gegl_buffer_iterator_stop:

 * @iterator: a GeglBufferIterator

 *

 * Cancels the current iteration, freeing up any temporary resources. You have

 * to bail out of any loop you are currently.

 */

void                 gegl_buffer_iterator_stop  (GeglBufferIterator *iterator);

/**

 * gegl_buffer_iterator_next:

 * @iterator: a #GeglBufferIterator

 *

 * Do an iteration, this causes a new set of iterator->data[] to become

 * available if there is more data to process. Changed data from a previous

 * iteration step will also be saved now. When there is no more data to

 * be processed FALSE will be returned (and the iterator handle is no longer

 * valid).

 *

 * Returns: TRUE if there is more work FALSE if iteration is complete.

 */

gboolean             gegl_buffer_iterator_next (GeglBufferIterator *iterator);

#ifdef EXAMPLE

  GeglBufferIterator *gi;

  gi = gegl_buffer_iterator_new (buffer, roi,

                                 babl_format("Y' float"), GEGL_BUFFER_WRITE);

  while (gegl_buffer_iterator_next (gi))

    {

      gfloat *buf = gi->data[0];

      gint    i;

      for (i=0; i<gi->length; i++)

        {

          buf[i]=0.5;

        }

    }

#endif

#endif