// Return the CIE94 Delta E
double LCMSEXPORT cmsCIE94DeltaE(LPcmsCIELab Lab1, LPcmsCIELab Lab2)
{
cmsCIELCh LCh1, LCh2;
double dE, dL, dC, dh, dhsq;
double c12, sc, sh;
if (Lab1 ->L == 0 && Lab2 ->L == 0) return 0;
dL = fabs(Lab1 ->L - Lab2 ->L);
cmsLab2LCh(&LCh1, Lab1);
cmsLab2LCh(&LCh2, Lab2);
dC = fabs(LCh1.C - LCh2.C);
dE = cmsDeltaE(Lab1, Lab2);
dhsq = Sqr(dE) - Sqr(dL) - Sqr(dC);
if (dhsq < 0)
dh = 0;
else
dh = pow(dhsq, 0.5);
c12 = sqrt(LCh1.C * LCh2.C);
sc = 1.0 + (0.048 * c12);
sh = 1.0 + (0.014 * c12);
return sqrt(Sqr(dL) + Sqr(dC) / Sqr(sc) + Sqr(dh) / Sqr(sh));
}
// bfd - gets BFD(1:1) difference between Lab1, Lab2
double LCMSEXPORT cmsBFDdeltaE(LPcmsCIELab Lab1, LPcmsCIELab Lab2)
{
double lbfd1,lbfd2,AveC,Aveh,dE,deltaL,
deltaC,deltah,dc,t,g,dh,rh,rc,rt,bfd;
cmsCIELCh LCh1, LCh2;
if (Lab1 ->L == 0 && Lab2 ->L == 0) return 0;
lbfd1 = ComputeLBFD(Lab1);
lbfd2 = ComputeLBFD(Lab2);
deltaL = lbfd2 - lbfd1;
cmsLab2LCh(&LCh1, Lab1);
cmsLab2LCh(&LCh2, Lab2);
deltaC = LCh2.C - LCh1.C;
AveC = (LCh1.C+LCh2.C)/2;
Aveh = (LCh1.h+LCh2.h)/2;
dE = cmsDeltaE(Lab1, Lab2);
if (Sqr(dE)>(Sqr(Lab2->L-Lab1->L)+Sqr(deltaC)))
deltah = sqrt(Sqr(dE)-Sqr(Lab2->L-Lab1->L)-Sqr(deltaC));
else
deltah =0;
dc = 0.035 * AveC / (1 + 0.00365 * AveC)+0.521;
g = sqrt(Sqr(Sqr(AveC))/(Sqr(Sqr(AveC))+14000));
t = 0.627+(0.055*cos((Aveh-254)/(180/M_PI))-
0.040*cos((2*Aveh-136)/(180/M_PI))+
0.070*cos((3*Aveh-31)/(180/M_PI))+
0.049*cos((4*Aveh+114)/(180/M_PI))-
0.015*cos((5*Aveh-103)/(180/M_PI)));
dh = dc*(g*t+1-g);
rh = -0.260*cos((Aveh-308)/(180/M_PI))-
0.379*cos((2*Aveh-160)/(180/M_PI))-
0.636*cos((3*Aveh+254)/(180/M_PI))+
0.226*cos((4*Aveh+140)/(180/M_PI))-
0.194*cos((5*Aveh+280)/(180/M_PI));
rc = sqrt((AveC*AveC*AveC*AveC*AveC*AveC)/((AveC*AveC*AveC*AveC*AveC*AveC)+70000000));
rt = rh*rc;
bfd = sqrt(Sqr(deltaL)+Sqr(deltaC/dc)+Sqr(deltah/dh)+(rt*(deltaC/dc)*(deltah/dh)));
return bfd;
}
// cmc - CMC(1:1) difference between Lab1, Lab2
double LCMSEXPORT cmsCMCdeltaE(LPcmsCIELab Lab1, LPcmsCIELab Lab2)
{
double dE,dL,dC,dh,sl,sc,sh,t,f,cmc;
cmsCIELCh LCh1, LCh2;
if (Lab1 ->L == 0 && Lab2 ->L == 0) return 0;
cmsLab2LCh(&LCh1, Lab1);
cmsLab2LCh(&LCh2, Lab2);
dL = Lab2->L-Lab1->L;
dC = LCh2.C-LCh1.C;
dE = cmsDeltaE(Lab1, Lab2);
if (Sqr(dE)>(Sqr(dL)+Sqr(dC)))
dh = sqrt(Sqr(dE)-Sqr(dL)-Sqr(dC));
else
dh =0;
if ((LCh1.h > 164) && (LCh1.h<345))
t = 0.56 + fabs(0.2 * cos(((LCh1.h + 168)/(180/M_PI))));
else
t = 0.36 + fabs(0.4 * cos(((LCh1.h + 35 )/(180/M_PI))));
sc = 0.0638 * LCh1.C / (1 + 0.0131 * LCh1.C) + 0.638;
sl = 0.040975 * Lab1->L /(1 + 0.01765 * Lab1->L);
if (Lab1->L<16)
sl = 0.511;
f = sqrt((LCh1.C * LCh1.C * LCh1.C * LCh1.C)/((LCh1.C * LCh1.C * LCh1.C * LCh1.C)+1900));
sh = sc*(t*f+1-f);
cmc = sqrt(Sqr(dL/sl)+Sqr(dC/sc)+Sqr(dh/sh));
return cmc;
}
static
int GamutSampler(register const cmsUInt16Number In[], register cmsUInt16Number Out[], register void* Cargo)
{
GAMUTCHAIN* t = (GAMUTCHAIN* ) Cargo;
cmsCIELab LabIn1, LabOut1;
cmsCIELab LabIn2, LabOut2;
cmsUInt16Number Proof[cmsMAXCHANNELS], Proof2[cmsMAXCHANNELS];
cmsFloat64Number dE1, dE2, ErrorRatio;
// Assume in-gamut by default.
ErrorRatio = 1.0;
// Convert input to Lab
cmsDoTransform(t -> hInput, In, &LabIn1, 1);
// converts from PCS to colorant. This always
// does return in-gamut values,
cmsDoTransform(t -> hForward, &LabIn1, Proof, 1);
// Now, do the inverse, from colorant to PCS.
cmsDoTransform(t -> hReverse, Proof, &LabOut1, 1);
memmove(&LabIn2, &LabOut1, sizeof(cmsCIELab));
// Try again, but this time taking Check as input
cmsDoTransform(t -> hForward, &LabOut1, Proof2, 1);
cmsDoTransform(t -> hReverse, Proof2, &LabOut2, 1);
// Take difference of direct value
dE1 = cmsDeltaE(&LabIn1, &LabOut1);
// Take difference of converted value
dE2 = cmsDeltaE(&LabIn2, &LabOut2);
// if dE1 is small and dE2 is small, value is likely to be in gamut
if (dE1 < t->Thereshold && dE2 < t->Thereshold)
Out[0] = 0;
else {
// if dE1 is small and dE2 is big, undefined. Assume in gamut
if (dE1 < t->Thereshold && dE2 > t->Thereshold)
Out[0] = 0;
else
// dE1 is big and dE2 is small, clearly out of gamut
if (dE1 > t->Thereshold && dE2 < t->Thereshold)
Out[0] = (cmsUInt16Number) _cmsQuickFloor((dE1 - t->Thereshold) + .5);
else {
// dE1 is big and dE2 is also big, could be due to perceptual mapping
// so take error ratio
if (dE2 == 0.0)
ErrorRatio = dE1;
else
ErrorRatio = dE1 / dE2;
if (ErrorRatio > t->Thereshold)
Out[0] = (cmsUInt16Number) _cmsQuickFloor((ErrorRatio - t->Thereshold) + .5);
else
Out[0] = 0;
}
}
return TRUE;
}
// The CLUT will be stored at 16 bits, but calculations are performed at cmsFloat32Number precision
static
int BlackPreservingSampler(register const cmsUInt16Number In[], register cmsUInt16Number Out[], register void* Cargo)
{
int i;
cmsFloat32Number Inf[4], Outf[4];
cmsFloat32Number LabK[4];
cmsFloat64Number SumCMY, SumCMYK, Error, Ratio;
cmsCIELab ColorimetricLab, BlackPreservingLab;
PreserveKPlaneParams* bp = (PreserveKPlaneParams*) Cargo;
// Convert from 16 bits to floating point
for (i=0; i < 4; i++)
Inf[i] = (cmsFloat32Number) (In[i] / 65535.0);
// Get the K across Tone curve
LabK[3] = cmsEvalToneCurveFloat(bp ->KTone, Inf[3]);
// If going across black only, keep black only
if (In[0] == 0 && In[1] == 0 && In[2] == 0) {
Out[0] = Out[1] = Out[2] = 0;
Out[3] = _cmsQuickSaturateWord(LabK[3] * 65535.0);
return TRUE;
}
// Try the original transform,
cmsPipelineEvalFloat( Inf, Outf, bp ->cmyk2cmyk);
// Store a copy of the floating point result into 16-bit
for (i=0; i < 4; i++)
Out[i] = _cmsQuickSaturateWord(Outf[i] * 65535.0);
// Maybe K is already ok (mostly on K=0)
if ( fabs(Outf[3] - LabK[3]) < (3.0 / 65535.0) ) {
return TRUE;
}
// K differ, mesure and keep Lab measurement for further usage
// this is done in relative colorimetric intent
cmsDoTransform(bp->hProofOutput, Out, &ColorimetricLab, 1);
// Is not black only and the transform doesn't keep black.
// Obtain the Lab of output CMYK. After that we have Lab + K
cmsDoTransform(bp ->cmyk2Lab, Outf, LabK, 1);
// Obtain the corresponding CMY using reverse interpolation
// (K is fixed in LabK[3])
if (!cmsPipelineEvalReverseFloat(LabK, Outf, Outf, bp ->LabK2cmyk)) {
// Cannot find a suitable value, so use colorimetric xform
// which is already stored in Out[]
return TRUE;
}
// Make sure to pass thru K (which now is fixed)
Outf[3] = LabK[3];
// Apply TAC if needed
SumCMY = Outf[0] + Outf[1] + Outf[2];
SumCMYK = SumCMY + Outf[3];
if (SumCMYK > bp ->MaxTAC) {
Ratio = 1 - ((SumCMYK - bp->MaxTAC) / SumCMY);
if (Ratio < 0)
Ratio = 0;
}
else
Ratio = 1.0;
Out[0] = _cmsQuickSaturateWord(Outf[0] * Ratio * 65535.0); // C
Out[1] = _cmsQuickSaturateWord(Outf[1] * Ratio * 65535.0); // M
Out[2] = _cmsQuickSaturateWord(Outf[2] * Ratio * 65535.0); // Y
Out[3] = _cmsQuickSaturateWord(Outf[3] * 65535.0);
// Estimate the error (this goes 16 bits to Lab DBL)
cmsDoTransform(bp->hProofOutput, Out, &BlackPreservingLab, 1);
Error = cmsDeltaE(&ColorimetricLab, &BlackPreservingLab);
if (Error > bp -> MaxError)
bp->MaxError = Error;
return TRUE;
}
double dkCmsDeltaE(LPcmsCIELab Lab1, LPcmsCIELab Lab2)
{
return static_cast<double>( cmsDeltaE(static_cast<cmsCIELab*>( Lab1 ), static_cast<cmsCIELab*>( Lab2 )) );
}
LCMSAPI double LCMSEXPORT cmsEvalLUTreverse(LPLUT Lut, WORD Target[], WORD Result[], LPWORD Hint)
{
int i;
double error, LastError = 1E20;
cmsCIELab fx, Goal;
VEC3 tmp, tmp2, x;
MAT3 Jacobian;
WORD FixedK;
WORD LastResult[4];
// This is our Lab goal
cmsLabEncoded2Float(&Goal, Target);
// Special case for CMYK->Lab
if (Lut ->InputChan == 4)
FixedK = Target[3];
else
FixedK = 0;
// Take the hint as starting point if specified
if (Hint == NULL) {
// Begin at any point, we choose 1/3 of neutral CMY gray
x.n[0] = x.n[1] = x.n[2] = 0.3;
}
else {
FromEncoded(&x, Hint);
}
// Iterate
for (i = 0; i < INVERSION_MAX_ITERATIONS; i++) {
// Get beginning fx
EvalLUTdoubleKLab(Lut, &x, FixedK, &fx);
// Compute error
error = cmsDeltaE(&fx, &Goal);
// If not convergent, return last safe value
if (error >= LastError)
break;
// Keep latest values
LastError = error;
ToEncoded(LastResult, &x);
LastResult[3] = FixedK;
// Obtain slope
ComputeJacobianLab(Lut, &Jacobian, &x, FixedK);
// Solve system
tmp2.n[0] = fx.L - Goal.L;
tmp2.n[1] = fx.a - Goal.a;
tmp2.n[2] = fx.b - Goal.b;
if (!MAT3solve(&tmp, &Jacobian, &tmp2))
break;
// Move our guess
x.n[0] -= tmp.n[0];
x.n[1] -= tmp.n[1];
x.n[2] -= tmp.n[2];
// Some clipping....
VEC3saturate(&x);
}
Result[0] = LastResult[0];
Result[1] = LastResult[1];
Result[2] = LastResult[2];
Result[3] = LastResult[3];
return LastError;
}
static
int GamutSampler(register WORD In[], register WORD Out[], register LPVOID Cargo)
{
LPGAMUTCHAIN t = (LPGAMUTCHAIN) Cargo;
WORD Proof[MAXCHANNELS], Check[MAXCHANNELS];
WORD Proof2[MAXCHANNELS], Check2[MAXCHANNELS];
cmsCIELab LabIn1, LabOut1;
cmsCIELab LabIn2, LabOut2;
double dE1, dE2, ErrorRatio;
// Assume in-gamut by default.
dE1 = 0.;
dE2 = 0;
ErrorRatio = 1.0;
// Any input space? I can use In[] no matter channels
// because is just one pixel
if (t -> hInput != NULL) cmsDoTransform(t -> hInput, In, In, 1);
// converts from PCS to colorant. This always
// does return in-gamut values,
cmsDoTransform(t -> hForward, In, Proof, 1);
// Now, do the inverse, from colorant to PCS.
cmsDoTransform(t -> hReverse, Proof, Check, 1);
// Try again, but this time taking Check as input
cmsDoTransform(t -> hForward, Check, Proof2, 1);
cmsDoTransform(t -> hReverse, Proof2, Check2, 1);
// Does the transform returns out-of-gamut?
if (Check[0] == 0xFFFF &&
Check[1] == 0xFFFF &&
Check[2] == 0xFFFF)
Out[0] = 0xFF00; // Out of gamut!
else {
// Transport encoded values
cmsLabEncoded2Float(&LabIn1, In);
cmsLabEncoded2Float(&LabOut1, Check);
// Take difference of direct value
dE1 = cmsDeltaE(&LabIn1, &LabOut1);
cmsLabEncoded2Float(&LabIn2, Check);
cmsLabEncoded2Float(&LabOut2, Check2);
// Take difference of converted value
dE2 = cmsDeltaE(&LabIn2, &LabOut2);
// if dE1 is small and dE2 is small, value is likely to be in gamut
if (dE1 < t->Thereshold && dE2 < t->Thereshold)
Out[0] = 0;
else
// if dE1 is small and dE2 is big, undefined. Assume in gamut
if (dE1 < t->Thereshold && dE2 > t->Thereshold)
Out[0] = 0;
else
// dE1 is big and dE2 is small, clearly out of gamut
if (dE1 > t->Thereshold && dE2 < t->Thereshold)
Out[0] = (WORD) _cmsQuickFloor((dE1 - t->Thereshold) + .5);
else {
// dE1 is big and dE2 is also big, could be due to perceptual mapping
// so take error ratio
if (dE2 == 0.0)
ErrorRatio = dE1;
else
ErrorRatio = dE1 / dE2;
if (ErrorRatio > t->Thereshold)
Out[0] = (WORD) _cmsQuickFloor((ErrorRatio - t->Thereshold) + .5);
else
Out[0] = 0;
}
}
return TRUE;
}
