rawTherapee/rtengine/colortemp.cc

88 lines
2.5 KiB
C++

/*
* This file is part of RawTherapee.
*
* Copyright (c) 2004-2010 Gabor Horvath <hgabor@rawtherapee.com>
*
* RawTherapee 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 3 of the License, or
* (at your option) any later version.
*
* RawTherapee 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 RawTherapee. If not, see <http://www.gnu.org/licenses/>.
*/
#include <colortemp.h>
using namespace rtengine;
ColorTemp::ColorTemp (double t, double g) : temp(t), green(g) {
clip (temp, green);
}
void ColorTemp::clip (double &temp, double &green) {
if (temp < MINTEMP)
temp = MINTEMP;
else if (temp > MAXTEMP)
temp = MAXTEMP;
if (green < MINGREEN)
green = MINGREEN;
else if (green > MAXGREEN)
green = MAXGREEN;
}
void ColorTemp::mul2temp (double rmul, double gmul, double bmul, double& temp, double& green) {
double maxtemp=20000, mintemp=1000;
double tmpr, tmpg, tmpb;
temp=(maxtemp+mintemp)/2;
while (maxtemp-mintemp>1) {
temp2mul (temp, 1.0, tmpr, tmpg, tmpb);
if (tmpb/tmpr > bmul/rmul)
maxtemp = temp;
else
mintemp = temp;
temp=(maxtemp+mintemp)/2;
}
green = (tmpg/tmpr) / (gmul/rmul);
clip (temp, green);
}
void ColorTemp::temp2mul (double temp, double green, double& rmul, double& gmul, double& bmul) {
clip (temp, green);
double xD;
if (temp<=4000) {
xD = 0.27475e9/(temp*temp*temp) - 0.98598e6/(temp*temp) + 1.17444e3/temp + 0.145986;
} else if (temp<=7000) {
xD = -4.6070e9/(temp*temp*temp) + 2.9678e6/(temp*temp) + 0.09911e3/temp + 0.244063;
} else {
xD = -2.0064e9/(temp*temp*temp) + 1.9018e6/(temp*temp) + 0.24748e3/temp + 0.237040;
}
double yD = -3.0*xD*xD + 2.87*xD - 0.275;
double X = xD/yD;
double Y = 1.0;
double Z = (1.0-xD-yD)/yD;
rmul = X * 3.24071 - Y * 1.53726 - Z * 0.498571;
gmul = - X * 0.969258 + Y * 1.87599 + Z * 0.0415557;
bmul = X * 0.0556352 - Y * 0.203996 + Z * 1.05707;
gmul /= green;
double max = rmul;
if (gmul>max) max = gmul;
if (bmul>max) max = bmul;
rmul /= max;
gmul /= max;
bmul /= max;
}