gstreamer/gst/geometrictransform/gstsquare.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 "gstsquare.h"

GST_DEBUG_CATEGORY_STATIC (gst_square_debug);
#define GST_CAT_DEFAULT gst_square_debug

GST_BOILERPLATE (GstSquare, gst_square, GstGeometricTransform,
    GST_TYPE_GEOMETRIC_TRANSFORM);

/* GObject vmethod implementations */

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

  gst_element_class_set_details_simple (element_class,
      "square",
      "Transform/Effect/Video",
      "Distort center part of the image into a square",
      "Filippo Argiolas <filippo.argiolas@gmail.com");
}

static gboolean
square_map (GstGeometricTransform * gt, gint x, gint y, gdouble * in_x,
    gdouble * in_y)
{
  GstSquare *square = GST_SQUARE_CAST (gt);
  gdouble norm_x;
  gdouble norm_y;

  gdouble width = gt->width;
  gdouble height = gt->height;

  /* normalize in ((-1.0, -1.0), (1.0, 1.0) */
  norm_x = 2.0 * x / width - 1.0;
  norm_y = 2.0 * y / height - 1.0;

  /* transform */
  /* zoom at the center, smoothstep around half quadrant and get back to normal */
  norm_x *= 0.5 * (1.0 + smoothstep (0.375, 0.625, ABS (norm_x)));
  norm_y *= 0.5 * (1.0 + smoothstep (0.375, 0.625, ABS (norm_y)));

  /* unnormalize */
  *in_x = 0.5 * (norm_x + 1.0) * width;
  *in_y = 0.5 * (norm_y + 1.0) * height;

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

  return TRUE;
}

static void
gst_square_class_init (GstSquareClass * 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 = square_map;
}

static void
gst_square_init (GstSquare * filter, GstSquareClass * gclass)
{
  GstGeometricTransform *gt = GST_GEOMETRIC_TRANSFORM (filter);

  gt->off_edge_pixels = GST_GT_OFF_EDGES_PIXELS_CLAMP;
}

gboolean
gst_square_plugin_init (GstPlugin * plugin)
{
  GST_DEBUG_CATEGORY_INIT (gst_square_debug, "square", 0, "square");

  return gst_element_register (plugin, "square", GST_RANK_NONE,
      GST_TYPE_SQUARE);
}