//---------------------------------------------------------------------------------
//
// Little Color Management System
// Copyright (c) 1998-2016 Marti Maria Saguer
//
// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the "Software"),
// to deal in the Software without restriction, including without limitation
// the rights to use, copy, modify, merge, publish, distribute, sublicense,
// and/or sell copies of the Software, and to permit persons to whom the Software
// is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO
// THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//
//---------------------------------------------------------------------------------
//
#include "lcms2_internal.h"
// D50 - Widely used
const cmsCIEXYZ* CMSEXPORT cmsD50_XYZ(void)
{
static cmsCIEXYZ D50XYZ = {cmsD50X, cmsD50Y, cmsD50Z};
return &D50XYZ;
}
const cmsCIExyY* CMSEXPORT cmsD50_xyY(void)
{
static cmsCIExyY D50xyY;
cmsXYZ2xyY(&D50xyY, cmsD50_XYZ());
return &D50xyY;
}
// Obtains WhitePoint from Temperature
cmsBool CMSEXPORT cmsWhitePointFromTemp(cmsCIExyY* WhitePoint, cmsFloat64Number TempK)
{
cmsFloat64Number x, y;
cmsFloat64Number T, T2, T3;
// cmsFloat64Number M1, M2;
_cmsAssert(WhitePoint != NULL);
T = TempK;
T2 = T*T; // Square
T3 = T2*T; // Cube
// For correlated color temperature (T) between 4000K and 7000K:
if (T >= 4000. && T <= 7000.)
{
x = -4.6070*(1E9/T3) + 2.9678*(1E6/T2) + 0.09911*(1E3/T) + 0.244063;
}
else
// or for correlated color temperature (T) between 7000K and 25000K:
if (T > 7000.0 && T <= 25000.0)
{
x = -2.0064*(1E9/T3) + 1.9018*(1E6/T2) + 0.24748*(1E3/T) + 0.237040;
}
else {
cmsSignalError(0, cmsERROR_RANGE, "cmsWhitePointFromTemp: invalid temp");
return FALSE;
}
// Obtain y(x)
y = -3.000*(x*x) + 2.870*x - 0.275;
// wave factors (not used, but here for futures extensions)
// M1 = (-1.3515 - 1.7703*x + 5.9114 *y)/(0.0241 + 0.2562*x - 0.7341*y);
// M2 = (0.0300 - 31.4424*x + 30.0717*y)/(0.0241 + 0.2562*x - 0.7341*y);
WhitePoint -> x = x;
WhitePoint -> y = y;
WhitePoint -> Y = 1.0;
return TRUE;
}
typedef struct {
cmsFloat64Number mirek; // temp (in microreciprocal kelvin)
cmsFloat64Number ut; // u coord of intersection w/ blackbody locus
cmsFloat64Number vt; // v coord of intersection w/ blackbody locus
cmsFloat64Number tt; // slope of ISOTEMPERATURE. line
} ISOTEMPERATURE;
static ISOTEMPERATURE isotempdata[] = {
// {Mirek, Ut, Vt, Tt }
{0, 0.18006, 0.26352, -0.24341},
{10, 0.18066, 0.26589, -0.25479},
{20, 0.18133, 0.26846, -0.26876},
{30, 0.18208, 0.27119, -0.28539},
{40, 0.18293, 0.27407, -0.30470},
{50, 0.18388, 0.27709, -0.32675},
{60, 0.18494, 0.28021, -0.35156},
{70, 0.18611, 0.28342, -0.37915},
{80, 0.18740, 0.28668, -0.40955},
{90, 0.18880, 0.28997, -0.44278},
{100, 0.19032, 0.29326, -0.47888},
{125, 0.19462, 0.30141, -0.58204},
{150, 0.19962, 0.30921, -0.70471},
{175, 0.20525, 0.31647, -0.84901},
{200, 0.21142, 0.32312, -1.0182 },
{225, 0.21807, 0.32909, -1.2168 },
{250, 0.22511, 0.33439, -1.4512 },
{275, 0.23247, 0.33904, -1.7298 },
{300, 0.24010, 0.34308, -2.0637 },
{325, 0.24702, 0.34655, -2.4681 },
{350, 0.25591, 0.34951, -2.9641 },
{375, 0.26400, 0.35200, -3.5814 },
{400, 0.27218, 0.35407, -4.3633 },
{425, 0.28039, 0.35577, -5.3762 },
{450, 0.28863, 0.35714, -6.7262 },
{475, 0.29685, 0.35823, -8.5955 },
{500, 0.30505, 0.35907, -11.324 },
{525, 0.31320, 0.35968, -15.628 },
{550, 0.32129, 0.36011, -23.325 },
{575, 0.32931, 0.36038, -40.770 },
{600, 0.33724, 0.36051, -116.45 }
};
#define NISO sizeof(isotempdata)/sizeof(ISOTEMPERATURE)
// Robertson's method
cmsBool CMSEXPORT cmsTempFromWhitePoint(cmsFloat64Number* TempK, const cmsCIExyY* WhitePoint)
{
cmsUInt32Number j;
cmsFloat64Number us,vs;
cmsFloat64Number uj,vj,tj,di,dj,mi,mj;
cmsFloat64Number xs, ys;
_cmsAssert(WhitePoint != NULL);
_cmsAssert(TempK != NULL);
di = mi = 0;
xs = WhitePoint -> x;
ys = WhitePoint -> y;
// convert (x,y) to CIE 1960 (u,WhitePoint)
us = (2*xs) / (-xs + 6*ys + 1.5);
vs = (3*ys) / (-xs + 6*ys + 1.5);
for (j=0; j < NISO; j++) {
uj = isotempdata[j].ut;
vj = isotempdata[j].vt;
tj = isotempdata[j].tt;
mj = isotempdata[j].mirek;
dj = ((vs - vj) - tj * (us - uj)) / sqrt(1.0 + tj * tj);
if ((j != 0) && (di/dj < 0.0)) {
// Found a match
*TempK = 1000000.0 / (mi + (di / (di - dj)) * (mj - mi));
return TRUE;
}
di = dj;
mi = mj;
}
// Not found
return FALSE;
}
// Compute chromatic adaptation matrix using Chad as cone matrix
static
cmsBool ComputeChromaticAdaptation(cmsMAT3* Conversion,
const cmsCIEXYZ* SourceWhitePoint,
const cmsCIEXYZ* DestWhitePoint,
const cmsMAT3* Chad)
{
cmsMAT3 Chad_Inv;
cmsVEC3 ConeSourceXYZ, ConeSourceRGB;
cmsVEC3 ConeDestXYZ, ConeDestRGB;
cmsMAT3 Cone, Tmp;
Tmp = *Chad;
if (!_cmsMAT3inverse(&Tmp, &Chad_Inv)) return FALSE;
_cmsVEC3init(&ConeSourceXYZ, SourceWhitePoint -> X,
SourceWhitePoint -> Y,
SourceWhitePoint -> Z);
_cmsVEC3init(&ConeDestXYZ, DestWhitePoint -> X,
DestWhitePoint -> Y,
DestWhitePoint -> Z);
_cmsMAT3eval(&ConeSourceRGB, Chad, &ConeSourceXYZ);
_cmsMAT3eval(&ConeDestRGB, Chad, &ConeDestXYZ);
// Build matrix
_cmsVEC3init(&Cone.v[0], ConeDestRGB.n[0]/ConeSourceRGB.n[0], 0.0, 0.0);
_cmsVEC3init(&Cone.v[1], 0.0, ConeDestRGB.n[1]/ConeSourceRGB.n[1], 0.0);
_cmsVEC3init(&Cone.v[2], 0.0, 0.0, ConeDestRGB.n[2]/ConeSourceRGB.n[2]);
// Normalize
_cmsMAT3per(&Tmp, &Cone, Chad);
_cmsMAT3per(Conversion, &Chad_Inv, &Tmp);
return TRUE;
}
// Returns the final chrmatic adaptation from illuminant FromIll to Illuminant ToIll
// The cone matrix can be specified in ConeMatrix. If NULL, Bradford is assumed
cmsBool _cmsAdaptationMatrix(cmsMAT3* r, const cmsMAT3* ConeMatrix, const cmsCIEXYZ* FromIll, const cmsCIEXYZ* ToIll)
{
cmsMAT3 LamRigg = {{ // Bradford matrix
{{ 0.8951, 0.2664, -0.1614 }},
{{ -0.7502, 1.7135, 0.0367 }},
{{ 0.0389, -0.0685, 1.0296 }}
}};
if (ConeMatrix == NULL)
ConeMatrix = &LamRigg;
return ComputeChromaticAdaptation(r, FromIll, ToIll, ConeMatrix);
}
// Same as anterior, but assuming D50 destination. White point is given in xyY
static
cmsBool _cmsAdaptMatrixToD50(cmsMAT3* r, const cmsCIExyY* SourceWhitePt)
{
cmsCIEXYZ Dn;
cmsMAT3 Bradford;
cmsMAT3 Tmp;
cmsxyY2XYZ(&Dn, SourceWhitePt);
if (!_cmsAdaptationMatrix(&Bradford, NULL, &Dn, cmsD50_XYZ())) return FALSE;
Tmp = *r;
_cmsMAT3per(r, &Bradford, &Tmp);
return TRUE;
}
// Build a White point, primary chromas transfer matrix from RGB to CIE XYZ
// This is just an approximation, I am not handling all the non-linear
// aspects of the RGB to XYZ process, and assumming that the gamma correction
// has transitive property in the tranformation chain.
//
// the alghoritm:
//
// - First I build the absolute conversion matrix using
// primaries in XYZ. This matrix is next inverted
// - Then I eval the source white point across this matrix
// obtaining the coeficients of the transformation
// - Then, I apply these coeficients to the original matrix
//
cmsBool _cmsBuildRGB2XYZtransferMatrix(cmsMAT3* r, const cmsCIExyY* WhitePt, const cmsCIExyYTRIPLE* Primrs)
{
cmsVEC3 WhitePoint, Coef;
cmsMAT3 Result, Primaries;
cmsFloat64Number xn, yn;
cmsFloat64Number xr, yr;
cmsFloat64Number xg, yg;
cmsFloat64Number xb, yb;
xn = WhitePt -> x;
yn = WhitePt -> y;
xr = Primrs -> Red.x;
yr = Primrs -> Red.y;
xg = Primrs -> Green.x;
yg = Primrs -> Green.y;
xb = Primrs -> Blue.x;
yb = Primrs -> Blue.y;
// Build Primaries matrix
_cmsVEC3init(&Primaries.v[0], xr, xg, xb);
_cmsVEC3init(&Primaries.v[1], yr, yg, yb);
_cmsVEC3init(&Primaries.v[2], (1-xr-yr), (1-xg-yg), (1-xb-yb));
// Result = Primaries ^ (-1) inverse matrix
if (!_cmsMAT3inverse(&Primaries, &Result))
return FALSE;
_cmsVEC3init(&WhitePoint, xn/yn, 1.0, (1.0-xn-yn)/yn);
// Across inverse primaries ...
_cmsMAT3eval(&Coef, &Result, &WhitePoint);
// Give us the Coefs, then I build transformation matrix
_cmsVEC3init(&r -> v[0], Coef.n[VX]*xr, Coef.n[VY]*xg, Coef.n[VZ]*xb);
_cmsVEC3init(&r -> v[1], Coef.n[VX]*yr, Coef.n[VY]*yg, Coef.n[VZ]*yb);
_cmsVEC3init(&r -> v[2], Coef.n[VX]*(1.0-xr-yr), Coef.n[VY]*(1.0-xg-yg), Coef.n[VZ]*(1.0-xb-yb));
return _cmsAdaptMatrixToD50(r, WhitePt);
}
// Adapts a color to a given illuminant. Original color is expected to have
// a SourceWhitePt white point.
cmsBool CMSEXPORT cmsAdaptToIlluminant(cmsCIEXYZ* Result,
const cmsCIEXYZ* SourceWhitePt,
const cmsCIEXYZ* Illuminant,
const cmsCIEXYZ* Value)
{
cmsMAT3 Bradford;
cmsVEC3 In, Out;
_cmsAssert(Result != NULL);
_cmsAssert(SourceWhitePt != NULL);
_cmsAssert(Illuminant != NULL);
_cmsAssert(Value != NULL);
if (!_cmsAdaptationMatrix(&Bradford, NULL, SourceWhitePt, Illuminant)) return FALSE;
_cmsVEC3init(&In, Value -> X, Value -> Y, Value -> Z);
_cmsMAT3eval(&Out, &Bradford, &In);
Result -> X = Out.n[0];
Result -> Y = Out.n[1];
Result -> Z = Out.n[2];
return TRUE;
}