gstreamer/gst/geometrictransform/gstmirror.c

/*
 * GStreamer
 * Copyright (C) 2010 Filippo Argiolas <filippo.argiolas@gmail.com>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 *
 * Alternatively, the contents of this file may be used under the
 * GNU Lesser General Public License Version 2.1 (the "LGPL"), in
 * which case the following provisions apply instead of the ones
 * mentioned above:
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 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
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */

#ifdef HAVE_CONFIG_H
#  include <config.h>
#endif

#include <gst/gst.h>
#include <math.h>

#include "gstmirror.h"

GST_DEBUG_CATEGORY_STATIC (gst_mirror_debug);
#define GST_CAT_DEFAULT gst_mirror_debug

GST_BOILERPLATE (GstMirror, gst_mirror, GstGeometricTransform,
    GST_TYPE_GEOMETRIC_TRANSFORM);

/* GObject vmethod implementations */

static void
gst_mirror_base_init (gpointer gclass)
{
  GstElementClass *element_class = GST_ELEMENT_CLASS (gclass);

  gst_element_class_set_details_simple (element_class,
      "mirror",
      "Transform/Effect/Video",
      "Split the image into two halves and reflect one over each other",
      "Filippo Argiolas <filippo.argiolas@gmail.com");
}

static gboolean
mirror_map (GstGeometricTransform * gt, gint x, gint y, gdouble * in_x,
    gdouble * in_y)
{
  GstMirror *mirror = GST_MIRROR_CAST (gt);

  gdouble hw = gt->width / 2.0;

  /* possible parameters:
     - split horizontal/vertical
     - reflect left half into right half or viceversa
     - reflect top half into bottom half or viceversa
   */
  if (x > hw)
    *in_x = gt->width - 1 - x;
  else
    *in_x = x;

  *in_y = y;

  GST_DEBUG_OBJECT (mirror, "Inversely mapped %d %d into %lf %lf",
      x, y, *in_x, *in_y);

  return TRUE;
}

static void
gst_mirror_class_init (GstMirrorClass * klass)
{
  GObjectClass *gobject_class;
  GstGeometricTransformClass *gstgt_class;

  gobject_class = (GObjectClass *) klass;
  gstgt_class = (GstGeometricTransformClass *) klass;

  parent_class = g_type_class_peek_parent (klass);

  gstgt_class->map_func = mirror_map;
}

static void
gst_mirror_init (GstMirror * filter, GstMirrorClass * gclass)
{
  GstGeometricTransform *gt = GST_GEOMETRIC_TRANSFORM (filter);

  gt->off_edge_pixels = GST_GT_OFF_EDGES_PIXELS_CLAMP;
}

gboolean
gst_mirror_plugin_init (GstPlugin * plugin)
{
  GST_DEBUG_CATEGORY_INIT (gst_mirror_debug, "mirror", 0, "mirror");

  return gst_element_register (plugin, "mirror", GST_RANK_NONE,
      GST_TYPE_MIRROR);
}