Rename lut -> double_lut.

[libdcp.git] / src / modified_gamma_transfer_function.cc

diff --git a/src/modified_gamma_transfer_function.cc b/src/modified_gamma_transfer_function.cc
index 850c735118417df2c465942d9921bd222e73bcb0..a54a090a829ed40abd45893fd5c2be974f1c43ef 100644 (file)
--- a/src/modified_gamma_transfer_function.cc
+++ b/src/modified_gamma_transfer_function.cc
@@ -1,30 +1,53 @@
 /*
-    Copyright (C) 2012-2014 Carl Hetherington <cth@carlh.net>
+    Copyright (C) 2012-2021 Carl Hetherington <cth@carlh.net>
 
-    This program is free software; you can redistribute it and/or modify
+    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.
 
-    This program is distributed in the hope that it will be useful,
+    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 this program; if not, write to the Free Software
-    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+    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/modified_gamma_transfer_function.cc
+ *  @brief ModifiedGammaTransferFunction class
+ */
+
+
 #include "modified_gamma_transfer_function.h"
 #include <cmath>
 
+
+using std::dynamic_pointer_cast;
 using std::pow;
-using boost::shared_ptr;
-using boost::dynamic_pointer_cast;
+using std::shared_ptr;
+using std::vector;
 using namespace dcp;
 
+
 ModifiedGammaTransferFunction::ModifiedGammaTransferFunction (double power, double threshold, double A, double B)
        : _power (power)
        , _threshold (threshold)
@@ -34,28 +57,31 @@ ModifiedGammaTransferFunction::ModifiedGammaTransferFunction (double power, doub
 
 }
 
-double *
-ModifiedGammaTransferFunction::make_lut (int bit_depth, bool inverse) const
+
+vector<double>
+ModifiedGammaTransferFunction::make_double_lut(double from, double to, int bit_depth, bool inverse) const
 {
        int const bit_length = int(std::pow(2.0f, bit_depth));
-       double* lut = new double[bit_length];
+       auto lut = vector<double>(bit_length);
        if (inverse) {
                double const threshold = _threshold / _B;
                for (int i = 0; i < bit_length; ++i) {
-                       double const p = static_cast<double> (i) / (bit_length - 1);
-                       if (p > threshold) {
-                               lut[i] = (1 + _A) * pow (p, 1 / _power) - _A;
+                       double const p = static_cast<double>(i) / (bit_length - 1);
+                       double const q = (p * (to - from)) + from;
+                       if (q > threshold) {
+                               lut[i] = (1 + _A) * pow (q, 1 / _power) - _A;
                        } else {
-                               lut[i] = p * _B;
+                               lut[i] = q * _B;
                        }
                }
        } else {
                for (int i = 0; i < bit_length; ++i) {
-                       double const p = static_cast<double> (i) / (bit_length - 1);
-                       if (p > _threshold) {
-                               lut[i] = pow ((p + _A) / (1 + _A), _power);
+                       double const p = static_cast<double>(i) / (bit_length - 1);
+                       double const q = (p * (to - from)) + from;
+                       if (q > _threshold) {
+                               lut[i] = pow ((q + _A) / (1 + _A), _power);
                        } else {
-                               lut[i] = p / _B;
+                               lut[i] = q / _B;
                        }
                }
        }
@@ -63,18 +89,19 @@ ModifiedGammaTransferFunction::make_lut (int bit_depth, bool inverse) const
        return lut;
 }
 
+
 bool
 ModifiedGammaTransferFunction::about_equal (shared_ptr<const TransferFunction> other, double epsilon) const
 {
-       shared_ptr<const ModifiedGammaTransferFunction> o = dynamic_pointer_cast<const ModifiedGammaTransferFunction> (other);
+       auto o = dynamic_pointer_cast<const ModifiedGammaTransferFunction>(other);
        if (!o) {
                return false;
        }
 
        return (
-               fabs (_power - o->_power) < epsilon &&
-               fabs (_threshold - o->_threshold) < epsilon &&
-               fabs (_A - o->_A) < epsilon &&
-               fabs (_B - o->_B) < epsilon
+               fabs(_power - o->_power) < epsilon &&
+               fabs(_threshold - o->_threshold) < epsilon &&
+               fabs(_A - o->_A) < epsilon &&
+               fabs(_B - o->_B) < epsilon
                );
 }