1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
|
/*
* 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_details_simple (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);
}
|
