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143 lines
5 KiB
C
143 lines
5 KiB
C
/*
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* GStreamer
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* Copyright (C) 2010 Filippo Argiolas <filippo.argiolas@gmail.com>
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the "Software"),
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* to deal in the Software without restriction, including without limitation
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* the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
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* DEALINGS IN THE SOFTWARE.
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*
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* Alternatively, the contents of this file may be used under the
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* GNU Lesser General Public License Version 2.1 (the "LGPL"), in
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* which case the following provisions apply instead of the ones
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* mentioned above:
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Library General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Library General Public License for more details.
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*
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* You should have received a copy of the GNU Library General Public
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* License along with this library; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 02111-1307, USA.
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*/
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#ifdef HAVE_CONFIG_H
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# include <config.h>
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#endif
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#include <gst/gst.h>
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#include <math.h>
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#include "gstfisheye.h"
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GST_DEBUG_CATEGORY_STATIC (gst_fisheye_debug);
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#define GST_CAT_DEFAULT gst_fisheye_debug
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#define gst_fisheye_parent_class parent_class
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G_DEFINE_TYPE (GstFisheye, gst_fisheye, GST_TYPE_GEOMETRIC_TRANSFORM);
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static gboolean
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fisheye_map (GstGeometricTransform * gt, gint x, gint y, gdouble * in_x,
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gdouble * in_y)
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{
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#ifndef GST_DISABLE_GST_DEBUG
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GstFisheye *fisheye = GST_FISHEYE_CAST (gt);
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#endif
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gdouble norm_x;
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gdouble norm_y;
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gdouble r;
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gdouble width = gt->width;
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gdouble height = gt->height;
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/* normalize in ((-1.0, -1.0), (1.0, 1.0) */
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norm_x = 2.0 * x / width - 1.0;
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norm_y = 2.0 * y / height - 1.0;
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/* normalize radius to 1, simplifies following formula */
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r = sqrt ((norm_x * norm_x + norm_y * norm_y) / 2.0);
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/* the idea is roughly to map r to tan(r) */
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/* to avoid switching back and forth to polar coordinates use
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tangent expansion */
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/* r = a*r + br^3 + cr^5 + dr^7 + o(8)) */
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/* = r(a + br^2 + cr^4 + dr^6) */
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/* so we can just multiply both x and y by the quantity in parenthesis */
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/* forgetting about the tangent thing and simplifying things a
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little bit we have a first linear term that, inverted, gives
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the zoom amount in the center region (3x here), than a high
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power term that makes the function blow up at the edges and a
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quadratic term smooths the middle region */
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/* coefficients must sum up to 1 to keep vertices in the +-1
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square */
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/* obviously this is a poor and arbitrary implementation of a
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fisheye filter, if you have a more rigorous method or one
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that gives better results please step up */
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norm_x *= (0.33 + 0.1 * r * r + 0.57 * pow (r, 6.0));
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norm_y *= (0.33 + 0.1 * r * r + 0.57 * pow (r, 6.0));
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/* unnormalize */
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*in_x = 0.5 * (norm_x + 1.0) * width;
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*in_y = 0.5 * (norm_y + 1.0) * height;
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GST_DEBUG_OBJECT (fisheye, "Inversely mapped %d %d into %lf %lf",
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x, y, *in_x, *in_y);
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return TRUE;
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}
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static void
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gst_fisheye_class_init (GstFisheyeClass * klass)
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{
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GstElementClass *gstelement_class;
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GstGeometricTransformClass *gstgt_class;
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gstelement_class = (GstElementClass *) klass;
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gstgt_class = (GstGeometricTransformClass *) klass;
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parent_class = g_type_class_peek_parent (klass);
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gst_element_class_set_details_simple (gstelement_class,
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"fisheye",
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"Transform/Effect/Video",
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"Split the image into two halves and reflect one over each other",
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"Filippo Argiolas <filippo.argiolas@gmail.com>");
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gstgt_class->map_func = fisheye_map;
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}
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static void
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gst_fisheye_init (GstFisheye * filter)
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{
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GstGeometricTransform *gt = GST_GEOMETRIC_TRANSFORM (filter);
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gt->off_edge_pixels = GST_GT_OFF_EDGES_PIXELS_CLAMP;
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}
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gboolean
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gst_fisheye_plugin_init (GstPlugin * plugin)
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{
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GST_DEBUG_CATEGORY_INIT (gst_fisheye_debug, "fisheye", 0, "fisheye");
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return gst_element_register (plugin, "fisheye", GST_RANK_NONE,
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GST_TYPE_FISHEYE);
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}
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