Add tentative S-Gamut3/S-Log3 colourspace support.

1 files changed, 78 insertions, 0 deletions

diff --git a/src/s_gamut3_transfer_function.cc b/src/s_gamut3_transfer_function.cc
new file mode 100644
index 00000000..371aebac
--- /dev/null
+++ b/src/s_gamut3_transfer_function.cc
@@ -0,0 +1,78 @@
+/*
+    Copyright (C) 2012-2014 Carl Hetherington <cth@carlh.net>
+
+    This file is part of libdcp.
+
+    libdcp is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    libdcp 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 General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with libdcp.  If not, see <http://www.gnu.org/licenses/>.
+
+    In addition, as a special exception, the copyright holders give
+    permission to link the code of portions of this program with the
+    OpenSSL library under certain conditions as described in each
+    individual source file, and distribute linked combinations
+    including the two.
+
+    You must obey the GNU General Public License in all respects
+    for all of the code used other than OpenSSL.  If you modify
+    file(s) with this exception, you may extend this exception to your
+    version of the file(s), but you are not obligated to do so.  If you
+    do not wish to do so, delete this exception statement from your
+    version.  If you delete this exception statement from all source
+    files in the program, then also delete it here.
+*/
+
+/** @file  src/s_gamut3_transfer_function.cc
+ *  @brief SGamut3TransferFunction class.
+ */
+
+#include "s_gamut3_transfer_function.h"
+#include <cmath>
+
+using std::pow;
+using boost::shared_ptr;
+using boost::dynamic_pointer_cast;
+using namespace dcp;
+
+double *
+SGamut3TransferFunction::make_lut (int bit_depth, bool inverse) const
+{
+	int const bit_length = int(std::pow(2.0f, bit_depth));
+	double* lut = new double[bit_length];
+	if (inverse) {
+		for (int i = 0; i < bit_length; ++i) {
+			double const p = static_cast<double> (i) / (bit_length - 1);
+			if (p >= (0.01125 / 1023)) {
+				lut[i] = (420 + log10((p + 0.01) / (0.18 + 0.01)) * 261.5) / 1023;
+			} else {
+				lut[i] = (p * (171.2102946929 - 95) / 0.01125000 + 95) / 1023;
+			}
+		}
+	} else {
+		for (int i = 0; i < bit_length; ++i) {
+			double const p = static_cast<double> (i) / (bit_length - 1);
+			if (p >= (171.2102946929 / 1023)) {
+				lut[i] = pow(10, ((p * 1023 - 420) / 261.5)) * (0.18 + 0.01) - 0.01;
+			} else {
+				lut[i] = (p * 1023 - 95) * 0.01125000 / (171.2102946929 - 95);
+			}
+		}
+	}
+	return lut;
+}
+
+bool
+SGamut3TransferFunction::about_equal (shared_ptr<const TransferFunction> other, double) const
+{
+	shared_ptr<const SGamut3TransferFunction> o = dynamic_pointer_cast<const SGamut3TransferFunction> (other);
+	return static_cast<bool> (o);
+}