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/*
* 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 "gstfisheye.h"
GST_DEBUG_CATEGORY_STATIC (gst_fisheye_debug);
#define GST_CAT_DEFAULT gst_fisheye_debug
#define gst_fisheye_parent_class parent_class
G_DEFINE_TYPE (GstFisheye, gst_fisheye, GST_TYPE_GEOMETRIC_TRANSFORM);
static gboolean
fisheye_map (GstGeometricTransform * gt, gint x, gint y, gdouble * in_x,
gdouble * in_y)
{
#ifndef GST_DISABLE_GST_DEBUG
GstFisheye *fisheye = GST_FISHEYE_CAST (gt);
#endif
gdouble norm_x;
gdouble norm_y;
gdouble r;
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;
/* normalize radius to 1, simplifies following formula */
r = sqrt ((norm_x * norm_x + norm_y * norm_y) / 2.0);
/* the idea is roughly to map r to tan(r) */
/* to avoid switching back and forth to polar coordinates use
tangent expansion */
/* r = a*r + br^3 + cr^5 + dr^7 + o(8)) */
/* = r(a + br^2 + cr^4 + dr^6) */
/* so we can just multiply both x and y by the quantity in parenthesis */
/* forgetting about the tangent thing and simplifying things a
little bit we have a first linear term that, inverted, gives
the zoom amount in the center region (3x here), than a high
power term that makes the function blow up at the edges and a
quadratic term smooths the middle region */
/* coefficients must sum up to 1 to keep vertices in the +-1
square */
/* obviously this is a poor and arbitrary implementation of a
fisheye filter, if you have a more rigorous method or one
that gives better results please step up */
norm_x *= (0.33 + 0.1 * r * r + 0.57 * pow (r, 6.0));
norm_y *= (0.33 + 0.1 * r * r + 0.57 * pow (r, 6.0));
/* unnormalize */
*in_x = 0.5 * (norm_x + 1.0) * width;
*in_y = 0.5 * (norm_y + 1.0) * height;
GST_DEBUG_OBJECT (fisheye, "Inversely mapped %d %d into %lf %lf",
x, y, *in_x, *in_y);
return TRUE;
}
static void
gst_fisheye_class_init (GstFisheyeClass * klass)
{
GstElementClass *gstelement_class;
GstGeometricTransformClass *gstgt_class;
gstelement_class = (GstElementClass *) klass;
gstgt_class = (GstGeometricTransformClass *) klass;
parent_class = g_type_class_peek_parent (klass);
gst_element_class_set_metadata (gstelement_class,
"fisheye",
"Transform/Effect/Video",
"Split the image into two halves and reflect one over each other",
"Filippo Argiolas <filippo.argiolas@gmail.com>");
gstgt_class->map_func = fisheye_map;
}
static void
gst_fisheye_init (GstFisheye * filter)
{
GstGeometricTransform *gt = GST_GEOMETRIC_TRANSFORM (filter);
gt->off_edge_pixels = GST_GT_OFF_EDGES_PIXELS_CLAMP;
}
gboolean
gst_fisheye_plugin_init (GstPlugin * plugin)
{
GST_DEBUG_CATEGORY_INIT (gst_fisheye_debug, "fisheye", 0, "fisheye");
return gst_element_register (plugin, "fisheye", GST_RANK_NONE,
GST_TYPE_FISHEYE);
}
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