From 75788462338b1b4f464d075465da3cb372c40004 Mon Sep 17 00:00:00 2001 From: Carl Hetherington Date: Sat, 27 Dec 2014 20:02:16 +0000 Subject: Change colourspace handling round a bit: - move the essence of GammaLUT into TransferFunction and handle different bit depths more neatly - add ColourConversion to describe input gamma correction, colour transformation and then output gamma correction in one class. - add default ColourConversions for sRGB->XYZ, Rec709->XYZ and XYZ->RGB. --- src/gamma_transfer_function.cc | 55 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 55 insertions(+) create mode 100644 src/gamma_transfer_function.cc (limited to 'src/gamma_transfer_function.cc') diff --git a/src/gamma_transfer_function.cc b/src/gamma_transfer_function.cc new file mode 100644 index 00000000..b4aa20f1 --- /dev/null +++ b/src/gamma_transfer_function.cc @@ -0,0 +1,55 @@ +/* + Copyright (C) 2012-2014 Carl Hetherington + + This program 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, + 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. + +*/ + +#include "gamma_transfer_function.h" +#include + +using std::pow; +using boost::shared_ptr; +using boost::dynamic_pointer_cast; +using namespace dcp; + +GammaTransferFunction::GammaTransferFunction (float gamma) + : _gamma (gamma) +{ + +} + +float * +GammaTransferFunction::make_lut (int bit_depth) const +{ + int const bit_length = pow (2, bit_depth); + float* lut = new float[int(std::pow(2.0f, bit_depth))]; + for (int i = 0; i < bit_length; ++i) { + lut[i] = pow(float(i) / (bit_length - 1), _gamma); + } + + return lut; +} + +bool +GammaTransferFunction::about_equal (shared_ptr other, float epsilon) const +{ + shared_ptr o = dynamic_pointer_cast (other); + if (!o) { + return false; + } + + return fabs (_gamma - o->_gamma) < epsilon; +} -- cgit v1.2.3