Further patches to exposure and tone curve. Histogram now stays fixed in tone curve, but all sliders up to and including brightness/contrast are applied before tone curve histogram is calculated and displayed. Bug in tone curve interaction with highlight reconstruction is fixed.

rtengine/curves.cc

@@ -586,7 +586,7 @@ void CurveFactory::complexCurve (double ecomp, double black, double hlcompr, dou
 
 	
 	//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-	
+	/*
 	void CurveFactory::complexCurve (double ecomp, double black, double hlcompr, double shcompr, double br, double contr, double defmul, double gamma_, bool igamma, const std::vector<double>& curvePoints, unsigned int* histogram, float* hlCurve, float* shCurve, int* outCurve, unsigned int* outBeforeCCurveHistogram, int skip) {
 		
 		double def_mul = pow (2.0, defmul);
@@ -769,9 +769,192 @@ void CurveFactory::complexCurve (double ecomp, double black, double hlcompr, dou
 				outCurve[i] = (int) (65535.0 * dcurve[i]);
 		delete [] dcurve;
 	}
+	*/
+	//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 	
 	//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
+	void CurveFactory::complexCurve (double ecomp, double black, double hlcompr, double shcompr, double br, double contr, double defmul, double gamma_, bool igamma, const std::vector<double>& curvePoints, unsigned int* histogram, float* hlCurve, float* shCurve, int* outCurve, unsigned int* outBeforeCCurveHistogram, 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;
+		
+		// a: slope of the curve, black: starting point at the x axis
+		double a = pow (2.0, ecomp);
+		
+		// curve without contrast
+		double* dcurve = new double[65536];
+		
+		// check if contrast curve is needed
+		bool needcontrast = contr>0.00001 || contr<-0.00001;
+		
+		// check if inverse gamma is needed at the end
+		bool needigamma = igamma && gamma_>0;
+		
+		// create a curve if needed
+		Curve* tcurve = NULL;
+		if (curvePoints.size()>0 && curvePoints[0]!=0)
+			tcurve = new Curve (curvePoints, CURVES_MIN_POLY_POINTS/skip);
+		
+		// clear array that stores histogram valid before applying the custom curve
+		if (outBeforeCCurveHistogram)
+			memset (outBeforeCCurveHistogram, 0, 256*sizeof(int));
+		
+		//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+		// tone curve base. a: slope (from exp.comp.), b: black, def_mul: max. x value (can be>1), hr,sr: highlight,shadow recovery
+		//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+		
+		std::vector<double> brightcurvePoints;
+		brightcurvePoints.push_back((double)((CurveType)NURBS));
+		
+		brightcurvePoints.push_back(0); //black point.  Value in [0 ; 1] range
+		brightcurvePoints.push_back(0); //black point.  Value in [0 ; 1] range
+		
+		if(br>0) {
+			brightcurvePoints.push_back(0.1); //toe point
+			brightcurvePoints.push_back(0.1+br/150.0); //value at toe point
+			
+			brightcurvePoints.push_back(0.7); //shoulder point
+			brightcurvePoints.push_back(MIN(1.0,0.7+br/300.0)); //value at shoulder point
+		} else {
+			brightcurvePoints.push_back(0.1-br/150.0); //toe point
+			brightcurvePoints.push_back(0.1); //value at toe point
+			
+			brightcurvePoints.push_back(MIN(1.0,0.7-br/300.0)); //shoulder point
+			brightcurvePoints.push_back(0.7); //value at shoulder point
+		}
+		brightcurvePoints.push_back(1); // white point
+		brightcurvePoints.push_back(1); // value at white point
+		
+		Curve* brightcurve = NULL;
+		brightcurve = new Curve (brightcurvePoints, CURVES_MIN_POLY_POINTS/skip); // Actually, CURVES_MIN_POLY_POINTS = 1000,
+		//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+		
+		for (int i=0; i<=0xffff; i++) {
+			
+			// change to [0,1] range
+			double val = (double)i / 65535.0;
+			
+			// apply default multiplier (that is >1 if highlight recovery is on)
+			// val *= def_mul;
+			
+			// apply base curve, thus, exposure compensation and black point with shadow and highlight protection
+			val = basecurve (val*def_mul, a, 0, def_mul, hlcompr/100.0, 0);
+			//val = basecurve (val*def_mul, a, black, def_mul, hlcompr/100.0, 1.5*shcompr/100.0);
+			
+			hlCurve[i] = (65535.0 * CLIPD(val));
+			
+			//%%%%%%%%%%%%%%%%%%%%%%%%%%
+			// change to [0,1] range
+			val = (double)i / 65535.0;
+			
+			val = basecurve (val, 1, black, 1, 0, 1.5*shcompr/100.0);
+			
+			shCurve[i] = (65535.0 * CLIPD(val));
+			
+			//%%%%%%%%%%%%%%%%%%%%%%%%%%
+			// change to [0,1] range
+			val = (double)i / 65535.0;
+			
+			// gamma correction
+			if (gamma_>0) 
+				val = gamma (val, gamma_, start, slope, mul, add);
+			
+			// apply brightness curve
+			//val = brightness (val, br/100.0);
+			val = brightcurve->getVal (val);
+			
+			// store result in a temporary array
+			dcurve[i] = CLIPD(val);
+		}
+		
+		//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+		
+		//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+		
+		if (needcontrast) {  
+			// compute mean luminance of the image with the curve applied
+			int sum = 0;
+			double avg = 0; 
+			//double sqavg = 0;
+			for (int i=0; i<=0xffff; i++) {
+				avg += dcurve[(int)shCurve[(int)hlCurve[i]]] * histogram[i];
+				//sqavg += dcurve[i]*dcurve[i] * histogram[i];
+				sum += histogram[i];
+			}
+			avg /= sum;
+			//sqavg /= sum;
+			//double stddev = sqrt(sqavg-avg*avg);
+			
+			//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+			std::vector<double> contrastcurvePoints;
+			contrastcurvePoints.push_back((double)((CurveType)NURBS));
+			
+			contrastcurvePoints.push_back(0); //black point.  Value in [0 ; 1] range
+			contrastcurvePoints.push_back(0); //black point.  Value in [0 ; 1] range
+			
+			contrastcurvePoints.push_back(avg-avg*(0.6-contr/250.0)); //toe point
+			contrastcurvePoints.push_back(avg-avg*(0.6+contr/250.0)); //value at toe point
+			
+			contrastcurvePoints.push_back(avg+(1-avg)*(0.6-contr/250.0)); //shoulder point
+			contrastcurvePoints.push_back(avg+(1-avg)*(0.6+contr/250.0)); //value at shoulder point
+			
+			contrastcurvePoints.push_back(1); // white point
+			contrastcurvePoints.push_back(1); // value at white point
+			
+			Curve* contrastcurve = NULL;
+			contrastcurve = new Curve (contrastcurvePoints, CURVES_MIN_POLY_POINTS/skip); // Actually, CURVES_MIN_POLY_POINTS = 1000,
+			//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+			
+			// apply contrast enhancement
+			for (int i=0; i<=0xffff; i++) {
+				//double val = centercontrast (dcurve[i], contr_b, avg);
+				dcurve[i]  = contrastcurve->getVal (dcurve[i]);
+			}
+			delete contrastcurve;
+		}
+		//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+		
+		for (int i=0; i<=0xffff; i++) {
+			float val;
+			
+			// apply custom/parametric/NURBS curve, if any
+			if (tcurve) {
+				if (outBeforeCCurveHistogram) {
+					float hval = dcurve[(int)shCurve[(int)(hlCurve[i])]];
+					//if (needigamma)
+					//	hval = igamma2 (hval);
+					int hi = (int)(255.0*CLIPD(hval));
+					outBeforeCCurveHistogram[hi]+=histogram[i] ;
+				}
+				val = tcurve->getVal (dcurve[i]);
+			} else {
+				val = (dcurve[i]);
+			}
+			
+			// if inverse gamma is needed, do it (standard sRGB inverse gamma is applied)
+			if (needigamma)
+				val = igamma2 (val);
+			
+			outCurve[i] = (int) (65535.0 * val + 0.5);
+		}
+		
+		
+		delete [] dcurve;
+		delete tcurve;
+		delete brightcurve; 
+		if (outBeforeCCurveHistogram) {
+			//for (int i=0; i<256; i++) printf("i= %d bchist= %d \n",i,outBeforeCCurveHistogram[i]);
+		}
+		
+	}
 
 	
 	//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

rtengine/curves.h

@@ -104,7 +104,7 @@ class CurveFactory {
 				return y*clower2(x/m, slope*m/y, 2.0-sr);
 		} else {
 			double slope = a/(1-b);
-			double m = a*D>1 ? b/a+(0.25+0.75*(1-1/D))/slope : b+(1-b)/4;
+			double m = a*D>1 ? b/a+(0.25)/slope : b+(1-b)/4;
 			double y = a*D>1 ? 0.25 : (m-b/a)*slope;
 			if (x<=m)
 				return b==0 ? x*slope : clower (x/m, slope*m/y, sr) * y;

rtengine/improccoordinator.cc

@@ -376,14 +376,9 @@ void ImProcCoordinator::updateHistograms (int x1, int y1, int x2, int y2) {
     memset (ghist, 0, 256*sizeof(int));
     memset (bhist, 0, 256*sizeof(int));
 	
-	memset (bcrgbhist, 0, 256*sizeof(int));
-	memset (bcLhist, 0, 256*sizeof(int));
-
     for (int i=y1; i<y2; i++) {
         int ofs = (i*pW + x1)*3;
         for (int j=x1; j<x2; j++) {
-			int Y = CLIPTO((299*previmg->data[ofs]+587*previmg->data[ofs+1]+114*previmg->data[ofs+2]),0,255000)/1000;
-			bcrgbhist[Y]++;
             rhist[previmg->data[ofs++]]++;
             ghist[previmg->data[ofs++]]++;
             bhist[previmg->data[ofs++]]++;
@@ -394,7 +389,6 @@ void ImProcCoordinator::updateHistograms (int x1, int y1, int x2, int y2) {
     for (int i=y1; i<y2; i++)
         for (int j=x1; j<x2; j++) {
             Lhist[nprevl->L[i][j]/256]++;
-			bcLhist[nprevl->L[i][j]/256]++;
 		}
 	
 	/*for (int i=0; i<256; i++) {