# ../gegl/operation/gegl-operation-temporal.h

    /* This file is part of 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 2008 Øyvind Kolås
     */

    /* GeglOperationTemporal
     * Base class for operations that want access to previous frames in a video sequence,
     * it contains API to configure the amounts of frames to store as well as getting a
     * GeglBuffer pointing to any of the previously stored frames.
     */

    #ifndef __GEGL_OPERATION_TEMPORAL_H__
    #define __GEGL_OPERATION_TEMPORAL_H__

    #include "gegl-operation-filter.h"

    G_BEGIN_DECLS

    #define GEGL_TYPE_OPERATION_TEMPORAL            (gegl_operation_temporal_get_type ())
    #define GEGL_OPERATION_TEMPORAL(obj)            (G_TYPE_CHECK_INSTANCE_CAST ((obj), GEGL_TYPE_OPERATION_TEMPORAL, GeglOperationTemporal))
    #define GEGL_OPERATION_TEMPORAL_CLASS(klass)    (G_TYPE_CHECK_CLASS_CAST ((klass),  GEGL_TYPE_OPERATION_TEMPORAL, GeglOperationTemporalClass))
    #define GEGL_IS_OPERATION_TEMPORAL(obj)         (G_TYPE_CHECK_INSTANCE_TYPE ((obj), GEGL_TYPE_OPERATION_TEMPORAL))
    #define GEGL_IS_OPERATION_TEMPORAL_CLASS(klass) (G_TYPE_CHECK_CLASS_TYPE ((klass),  GEGL_TYPE_OPERATION_TEMPORAL))
    #define GEGL_OPERATION_TEMPORAL_GET_CLASS(obj)  (G_TYPE_INSTANCE_GET_CLASS ((obj),  GEGL_TYPE_OPERATION_TEMPORAL, GeglOperationTemporalClass))

    typedef struct _GeglOperationTemporal         GeglOperationTemporal;
    typedef struct _GeglOperationTemporalPrivate  GeglOperationTemporalPrivate;
    struct _GeglOperationTemporal
    {
      GeglOperationFilter parent_instance;
      GeglOperationTemporalPrivate *priv;
    };

    typedef struct _GeglOperationTemporalClass GeglOperationTemporalClass;
    struct _GeglOperationTemporalClass
    {
      GeglOperationFilterClass parent_class;
      gboolean (* process) (GeglOperation       *self,
                            GeglBuffer          *input,
                            GeglBuffer          *output,
                            const GeglRectangle *roi,
                            gint                 level);
      gpointer              pad[4];
    };

    GType gegl_operation_temporal_get_type (void) G_GNUC_CONST;

    void gegl_operation_temporal_set_history_length (GeglOperation *op,
                                                     gint           history_length);

    guint gegl_operation_temporal_get_history_length (GeglOperation *op);

    /* you need to unref the buffer when you're done with it */
    GeglBuffer *gegl_operation_temporal_get_frame (GeglOperation *op,
                                                   gint           frame);

    G_END_DECLS

    #endif