2 Copyright (C) 2014-2021 Carl Hetherington <cth@carlh.net>
4 This file is part of libdcp.
6 libdcp is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2 of the License, or
9 (at your option) any later version.
11 libdcp is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with libdcp. If not, see <http://www.gnu.org/licenses/>.
19 In addition, as a special exception, the copyright holders give
20 permission to link the code of portions of this program with the
21 OpenSSL library under certain conditions as described in each
22 individual source file, and distribute linked combinations
25 You must obey the GNU General Public License in all respects
26 for all of the code used other than OpenSSL. If you modify
27 file(s) with this exception, you may extend this exception to your
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34 #include "colour_conversion.h"
35 #include "gamma_transfer_function.h"
36 #include "modified_gamma_transfer_function.h"
37 #include "s_gamut3_transfer_function.h"
38 #include "identity_transfer_function.h"
39 #include "dcp_assert.h"
40 #include <boost/numeric/ublas/matrix.hpp>
41 #include <boost/numeric/ublas/lu.hpp>
42 #include <boost/numeric/ublas/io.hpp>
44 using std::shared_ptr;
45 using std::make_shared;
46 using boost::optional;
49 ColourConversion const &
50 ColourConversion::srgb_to_xyz ()
52 static ColourConversion* c = new ColourConversion (
53 make_shared<ModifiedGammaTransferFunction>(2.4, 0.04045, 0.055, 12.92),
55 Chromaticity (0.64, 0.33),
56 Chromaticity (0.3, 0.6),
57 Chromaticity (0.15, 0.06),
59 optional<Chromaticity> (),
60 make_shared<GammaTransferFunction>(2.6)
65 ColourConversion const &
66 ColourConversion::rec601_to_xyz ()
68 static ColourConversion* c = new ColourConversion (
69 make_shared<GammaTransferFunction>(2.2),
71 Chromaticity (0.64, 0.33),
72 Chromaticity (0.3, 0.6),
73 Chromaticity (0.15, 0.06),
75 optional<Chromaticity> (),
76 make_shared<GammaTransferFunction>(2.6)
81 ColourConversion const &
82 ColourConversion::rec709_to_xyz ()
84 static ColourConversion* c = new ColourConversion (
85 make_shared<GammaTransferFunction>(2.2),
87 Chromaticity (0.64, 0.33),
88 Chromaticity (0.3, 0.6),
89 Chromaticity (0.15, 0.06),
91 optional<Chromaticity> (),
92 make_shared<GammaTransferFunction>(2.6)
97 ColourConversion const &
98 ColourConversion::p3_to_xyz ()
100 static ColourConversion* c = new ColourConversion (
101 make_shared<GammaTransferFunction>(2.6),
103 Chromaticity (0.68, 0.32),
104 Chromaticity (0.265, 0.69),
105 Chromaticity (0.15, 0.06),
106 Chromaticity (0.314, 0.351),
107 optional<Chromaticity> (),
108 make_shared<GammaTransferFunction>(2.6)
113 ColourConversion const &
114 ColourConversion::rec1886_to_xyz ()
116 /* According to Olivier on DCP-o-matic bug #832, Rec. 1886 is Rec. 709 with
117 2.4 gamma, so here goes ...
119 static ColourConversion* c = new ColourConversion (
120 make_shared<GammaTransferFunction>(2.4),
122 Chromaticity (0.64, 0.33),
123 Chromaticity (0.3, 0.6),
124 Chromaticity (0.15, 0.06),
125 Chromaticity::D65 (),
126 optional<Chromaticity> (),
127 make_shared<GammaTransferFunction>(2.6)
132 ColourConversion const &
133 ColourConversion::rec2020_to_xyz ()
135 static ColourConversion* c = new ColourConversion (
136 make_shared<GammaTransferFunction>(2.4),
138 Chromaticity (0.708, 0.292),
139 Chromaticity (0.170, 0.797),
140 Chromaticity (0.131, 0.046),
141 Chromaticity::D65 (),
142 optional<Chromaticity> (),
143 make_shared<GammaTransferFunction>(2.6)
148 /** Sony S-Gamut3/S-Log3 */
149 ColourConversion const &
150 ColourConversion::s_gamut3_to_xyz ()
152 static ColourConversion* c = new ColourConversion (
153 make_shared<SGamut3TransferFunction>(),
155 Chromaticity (0.73, 0.280),
156 Chromaticity (0.140, 0.855),
157 Chromaticity (0.100, -0.050),
158 Chromaticity::D65 (),
159 optional<Chromaticity> (),
160 make_shared<IdentityTransferFunction>()
167 ColourConversion::ColourConversion (
168 shared_ptr<const TransferFunction> in,
174 optional<Chromaticity> adjusted_white,
175 shared_ptr<const TransferFunction> out
178 , _yuv_to_rgb (yuv_to_rgb)
183 , _adjusted_white (adjusted_white)
190 ColourConversion::about_equal (ColourConversion const & other, float epsilon) const
192 if (!_in->about_equal (other._in, epsilon) ||
193 _yuv_to_rgb != other._yuv_to_rgb ||
194 !_red.about_equal (other._red, epsilon) ||
195 !_green.about_equal (other._green, epsilon) ||
196 !_blue.about_equal (other._blue, epsilon) ||
197 !_white.about_equal (other._white, epsilon) ||
198 (!_out && other._out) ||
199 (_out && !other._out) ||
200 (_out && !_out->about_equal (other._out, epsilon))) {
204 if (!_adjusted_white && !other._adjusted_white) {
209 _adjusted_white && other._adjusted_white &&
210 fabs (_adjusted_white.get().x - other._adjusted_white.get().x) < epsilon &&
211 fabs (_adjusted_white.get().y - other._adjusted_white.get().y) < epsilon
216 /* Otherwise one has an adjusted white and other hasn't, or they both have but different */
220 boost::numeric::ublas::matrix<double>
221 ColourConversion::rgb_to_xyz () const
223 /* See doc/design/colour.tex */
225 double const D = (_red.x - _white.x) * (_white.y - _blue.y) - (_white.x - _blue.x) * (_red.y - _white.y);
226 double const E = (_white.x - _green.x) * (_red.y - _white.y) - (_red.x - _white.x) * (_white.y - _green.y);
227 double const F = (_white.x - _green.x) * (_white.y - _blue.y) - (_white.x - _blue.x) * (_white.y - _green.y);
228 double const P = _red.y + _green.y * D / F + _blue.y * E / F;
230 boost::numeric::ublas::matrix<double> C (3, 3);
231 C(0, 0) = _red.x / P;
232 C(0, 1) = _green.x * D / (F * P);
233 C(0, 2) = _blue.x * E / (F * P);
234 C(1, 0) = _red.y / P;
235 C(1, 1) = _green.y * D / (F * P);
236 C(1, 2) = _blue.y * E / (F * P);
237 C(2, 0) = _red.z() / P;
238 C(2, 1) = _green.z() * D / (F * P);
239 C(2, 2) = _blue.z() * E / (F * P);
243 boost::numeric::ublas::matrix<double>
244 ColourConversion::xyz_to_rgb () const
246 boost::numeric::ublas::matrix<double> A (rgb_to_xyz ());
248 /* permutation matrix for the LU-factorization */
249 boost::numeric::ublas::permutation_matrix<std::size_t> pm (A.size1 ());
251 /* perform LU-factorization */
252 int const r = lu_factorize (A, pm);
255 /* create identity matrix of inverse */
256 boost::numeric::ublas::matrix<double> xyz_to_rgb (3, 3);
257 xyz_to_rgb.assign (boost::numeric::ublas::identity_matrix<double> (A.size1 ()));
259 /* backsubstitute to get the inverse */
260 lu_substitute (A, pm, xyz_to_rgb);
265 boost::numeric::ublas::matrix<double>
266 ColourConversion::bradford () const
268 if (!_adjusted_white || fabs (_adjusted_white.get().x) < 1e-6 || fabs (_adjusted_white.get().y) < 1e-6) {
269 boost::numeric::ublas::matrix<double> B = boost::numeric::ublas::zero_matrix<double> (3, 3);
276 /* See doc/design/colour.tex */
278 boost::numeric::ublas::matrix<double> M (3, 3);
289 boost::numeric::ublas::matrix<double> Mi (3, 3);
290 Mi(0, 0) = 0.9869929055;
291 Mi(0, 1) = -0.1470542564;
292 Mi(0, 2) = 0.1599626517;
293 Mi(1, 0) = 0.4323052697;
294 Mi(1, 1) = 0.5183602715;
295 Mi(1, 2) = 0.0492912282;
296 Mi(2, 0) = -0.0085286646;
297 Mi(2, 1) = 0.0400428217;
298 Mi(2, 2) = 0.9684866958;
300 boost::numeric::ublas::matrix<double> Gp (3, 1);
301 Gp(0, 0) = _white.x / _white.y;
303 Gp(2, 0) = (1 - _white.x - _white.y) / _white.y;
305 boost::numeric::ublas::matrix<double> G = boost::numeric::ublas::prod (M, Gp);
307 boost::numeric::ublas::matrix<double> Hp (3, 1);
308 Hp(0, 0) = _adjusted_white.get().x / _adjusted_white.get().y;
310 Hp(2, 0) = (1 - _adjusted_white.get().x - _adjusted_white.get().y) / _adjusted_white.get().y;
312 boost::numeric::ublas::matrix<double> H = boost::numeric::ublas::prod (M, Hp);
314 boost::numeric::ublas::matrix<double> C = boost::numeric::ublas::zero_matrix<double> (3, 3);
315 C(0, 0) = H(0, 0) / G(0, 0);
316 C(1, 1) = H(1, 0) / G(1, 0);
317 C(2, 2) = H(2, 0) / G(2, 0);
319 boost::numeric::ublas::matrix<double> CM = boost::numeric::ublas::prod (C, M);
320 return boost::numeric::ublas::prod (Mi, CM);