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Issue 2850: normalized RGB-pipeline curve gammas to sRGB, make curve algorithms operate on linear image data

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This commit is contained in:
torger
2015-07-23 21:34:00 +02:00
parent db306ccfed
commit b2836b388f
10 changed files with 80 additions and 100 deletions
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87
rtengine/curves.cc
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@@ -340,6 +340,11 @@ void CurveFactory::curveBW (
LUTu & histogrambw, LUTu & outBeforeCCurveHistogrambw,//for Luminance
ToneCurve & customToneCurvebw1, ToneCurve & customToneCurvebw2, int skip)
{
const float gamma_ = Color::sRGBGamma;
const float start = expf(gamma_*logf( -0.055 / ((1.0/gamma_-1.0)*1.055 )));
const float slope = 1.055 * powf (start, 1.0/gamma_-1) - 0.055/start;
const float mul = 1.055;
const float add = 0.055;
outBeforeCCurveHistogrambw.clear();
bool histNeeded = false;
@@ -355,7 +360,7 @@ void CurveFactory::curveBW (
}
if (tcurve) {
if (!tcurve->isIdentity())
customToneCurvebw2.Set(tcurve);
customToneCurvebw2.Set(tcurve, gamma_, start, slope, mul, add);
delete tcurve;
tcurve = NULL;
}
@@ -370,7 +375,7 @@ void CurveFactory::curveBW (
}
if (tcurve) {
if (!tcurve->isIdentity())
customToneCurvebw1.Set(tcurve);
customToneCurvebw1.Set(tcurve, gamma_, start, slope, mul, add);
delete tcurve;
tcurve = NULL;
}
@@ -617,7 +622,7 @@ void CurveFactory::curveToningLL ( bool & llctoningutili,const std::vector<doubl
//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
SSEFUNCTION void CurveFactory::complexCurve (double ecomp, double black, double hlcompr, double hlcomprthresh,
double shcompr, double br, double contr, double gamma_, bool igamma_,
double shcompr, double br, double contr,
procparams::ToneCurveParams::eTCModeId curveMode, const std::vector<double>& curvePoints,
procparams::ToneCurveParams::eTCModeId curveMode2, const std::vector<double>& curvePoints2,
LUTu & histogram, LUTu & histogramCropped,
@@ -626,32 +631,17 @@ void CurveFactory::curveToningLL ( bool & llctoningutili,const std::vector<doubl
ToneCurve & customToneCurve1,
ToneCurve & customToneCurve2,
int skip) {
//double def_mul = pow (2.0, defmul);
/*printf ("def_mul= %f ecomp= %f black= %f hlcompr= %f shcompr= %f br= %f contr= %f defmul= %f
gamma= %f, skip= %d \n",def_mul,ecomp,black,hlcompr,shcompr,br,contr,defmul,gamma_,skip);*/
// compute parameters of the gamma curve
/*double start = exp(gamma_*log( -0.099 / ((1.0/gamma_-1.0)*1.099 )));
double slope = 1.099 * pow (start, 1.0/gamma_-1) - 0.099/start;
double mul = 1.099;
double add = 0.099;
// gamma BT709*/
//normalize gamma to sRGB
double start = exp(gamma_*log( -0.055 / ((1.0/gamma_-1.0)*1.055 )));
double slope = 1.055 * pow (start, 1.0/gamma_-1) - 0.055/start;
double mul = 1.055;
double add = 0.055;
// the curve shapes are defined in sRGB gamma, but the output curves will operate on linear floating point data,
// hence we do both forward and inverse gamma conversions here.
const float gamma_ = Color::sRGBGamma;
const float start = expf(gamma_*logf( -0.055 / ((1.0/gamma_-1.0)*1.055 )));
const float slope = 1.055 * powf (start, 1.0/gamma_-1) - 0.055/start;
const float mul = 1.055;
const float add = 0.055;
// a: slope of the curve, black: starting point at the x axis
double a = pow (2.0, ecomp);
// check if inverse gamma is needed at the end
bool needigamma = igamma_ && gamma_>1.;
const float a = powf (2.0, ecomp);
// clear array that stores histogram valid before applying the custom curve
outBeforeCCurveHistogram.clear();
@@ -727,9 +717,8 @@ void CurveFactory::curveToningLL ( bool & llctoningutili,const std::vector<doubl
float val2 = simplebasecurve (val, black, 0.015*shcompr);
shCurve[0] = CLIPD(val2)/val;
val = 0.0;
// gamma correction
if (gamma_>1.)
val = gamma (val, gamma_, start, slope, mul, add);
// gamma correction
val = gamma (val, gamma_, start, slope, mul, add);
// apply brightness curve
if (brightcurve)
@@ -747,8 +736,7 @@ void CurveFactory::curveToningLL ( bool & llctoningutili,const std::vector<doubl
shCurve[i] = CLIPD(val2)/val;
// gamma correction
if (gamma_>1.)
val = gamma (val, gamma_, start, slope, mul, add);
val = gamma (val, gamma_, start, slope, mul, add);
// apply brightness curve
if (brightcurve)
@@ -825,7 +813,7 @@ void CurveFactory::curveToningLL ( bool & llctoningutili,const std::vector<doubl
}
if (tcurve) {
if (!tcurve->isIdentity())
customToneCurve2.Set(tcurve);
customToneCurve2.Set(tcurve, gamma_, start, slope, mul, add);
delete tcurve;
tcurve = NULL;
}
@@ -844,7 +832,7 @@ void CurveFactory::curveToningLL ( bool & llctoningutili,const std::vector<doubl
}
if (tcurve) {
if (!tcurve->isIdentity())
customToneCurve1.Set(tcurve);
customToneCurve1.Set(tcurve, gamma_, start, slope, mul, add);
delete tcurve;
tcurve = NULL;
}
@@ -904,11 +892,7 @@ void CurveFactory::curveToningLL ( bool & llctoningutili,const std::vector<doubl
int hi = (int)(255.0*(hval));
outBeforeCCurveHistogram[hi] += histogram/*Cropped*/[i] ;
}
// if inverse gamma is needed, do it (standard sRGB inverse gamma is applied)
if (needigamma)
val = igamma (val, gamma_, start, slope, mul, add);
val = igamma (val, gamma_, start, slope, mul, add);
outCurve[i] = (65535.f * val);
}
@@ -1137,7 +1121,13 @@ void CurveFactory::curveToningLL ( bool & llctoningutili,const std::vector<doubl
outCurve(65536, 0);
for (int i=0; i<65536; i++) {
// apply custom/parametric/NURBS curve, if any
float val = tcurve->getVal ((float)i/65536.0f);
// RGB curves are defined with sRGB gamma, but operate on linear data
float val = float(i)/65535.f;
val = CurveFactory::gamma2 (val);
val = tcurve->getVal(val);
val = CurveFactory::igamma2 (val);
//float val = tcurve->getVal ((float)i/65536.0f);
outCurve[i] = (65536.0f * val);
}
delete tcurve;
@@ -1165,9 +1155,20 @@ void ToneCurve::Reset() {
}
// Fill a LUT with X/Y, ranged 0xffff
void ToneCurve::Set(Curve *pCurve) {
lutToneCurve(65536);
for (int i=0; i<65536; i++) lutToneCurve[i] = pCurve->getVal(double(i)/65535.) * 65535.;
void ToneCurve::Set(Curve *pCurve, float gamma, float start, float slope, float mul, float add) {
lutToneCurve(65536);
if (gamma <= 0.0 || gamma == 1.) {
for (int i=0; i<65536; i++) lutToneCurve[i] = (float)pCurve->getVal(float(i)/65535.f) * 65535.f;
} else {
// apply gamma, that is 'pCurve' is defined with the given gamma and here we convert it to a curve in linear space
for (int i=0; i<65536; i++) {
float val = float(i)/65535.f;
val = CurveFactory::gamma (val, gamma, start, slope, mul, add);
val = pCurve->getVal(val);
val = CurveFactory::igamma (val, gamma, start, slope, mul, add);
lutToneCurve[i] = val * 65535.f;
}
}
}
void OpacityCurve::Reset() {