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argyllcms/xicc/cam02ref.h
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gronod 45bdf51201 Initial commit of v3.5.0
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/*
* cam02, unoptimised, untweaked reference version for testing.
* with optional trace/range error flags.
*
* Color Appearance Model.
*
* Author: Graeme W. Gill
* Date: 17/1/2004
* Version: 1.00
*
* This file is based on cam97s3.c by Graeme Gill.
*
* Copyright 2004, 2007 Graeme W. Gill
* Please refer to COPYRIGHT file for details.
* This material is licenced under the GNU AFFERO GENERAL PUBLIC LICENSE Version 3 :-
* see the License.txt file for licencing details.
*/
/* Note that XYZ values are normalised to 1.0 consistent */
/* with the ICC convention (not 100.0 as assumed by the CIECAM spec.) */
/* Note that all whites are assumed to be normalised (ie. Y = 1.0) */
#define HHKR_MUL 0.25
#undef DIAG /* Print internal value diagnostics for each conversion */
/* ---------------------------------- */
#ifdef NEVER
struct _cam02ref {
/* Public: */
void (*del)(struct _cam02ref *s); /* We're done with it */
int (*set_view)(
struct _cam02ref *s,
ViewingCondition Ev, /* Enumerated Viewing Condition */
double Wxyz[3], /* Reference/Adapted White XYZ (Y scale 1.0) */
double La, /* Adapting/Surround Luminance cd/m^2 */
double Yb, /* Luminance of Background relative to reference white (range 0.0 .. 1.0) */
double Lv, /* Luminance of white in the Viewing/Scene/Image field (cd/m^2) */
/* Ignored if Ev is set */
double Yf, /* Flare as a fraction of the reference white (range 0.0 .. 1.0) */
double Yg, /* Glare as a fraction of the adapting/surround (range 0.0 .. 1.0) */
double Gxyz[3], /* The Glare white coordinates (typically the Ambient color) */
int hk, /* Flag, NZ to use Helmholtz-Kohlraush effect */
double hkscale, /* HK effect scaling factor */
double mtaf, /* Mid tone partial adapation factor from Wxyz to Wxyz2, <= 0.0 if none */
double Wxyz2[3] /* Mid tone Adapted White XYZ (Y range 0.0 .. 1.0) */
);
/* Conversions */
int (*XYZ_to_cam)(struct _cam02ref *s, double *out, double *in);
/* Private: */
/* Scene parameters */
ViewingCondition Ev; /* Enumerated Viewing Condition */
double Lv; /* Luminance of white in the Viewing/Image cd/m^2 */
double La; /* Adapting/Surround Luminance cd/m^2 */
double Wxyz[3]; /* Reference/Adapted White XYZ (Y range 0.0 .. 1.0) */
double Yb; /* Relative Luminance of Background to reference white (Y range 0.0 .. 1.0) */
double Yf; /* Flare as a fraction of the reference white (Y range 0.0 .. 1.0) */
double Fxyz[3]; /* The Flare white coordinates (typically the Ambient color) */
/* Internal parameters */
double C; /* Surround Impact */
double Nc; /* Chromatic Induction */
double F; /* Adaptation Degree */
/* Pre-computed values */
double Fsc; /* Flare scale */
double Fisc; /* Inverse flare scale */
double Fsxyz[3]; /* Scaled Flare color coordinates */
double rgbW[3]; /* Sharpened cone response white values */
double D; /* Degree of chromatic adaption */
double Drgb[3]; /* Chromatic transformation value */
double rgbcW[3]; /* Chromatically transformed white value */
double rgbpW[3]; /* Hunt-Pointer-Estevez cone response space white */
double n; /* Background induction factor */
double nn; /* Precomuted function of n */
double Fl; /* Lightness contrast factor ?? */
double Nbb; /* Background brightness induction factors */
double Ncb; /* Chromatic brightness induction factors */
double z; /* Base exponential nonlinearity */
double rgbaW[3]; /* Post-adapted cone response of white */
double Aw; /* Achromatic response of white */
/* Option flags */
int hk; /* Use Helmholtz-Kohlraush effect */
int trace; /* Trace internal values */
double range; /* Return error if there is a range error */
double nldlimit; /* range error if nlinear is less than this */
double jlimit; /* range error if J is less than this */
}; typedef struct _cam02ref cam02ref;
#else
typedef struct _cam02 cam02ref;
#endif
/* ---------------------------------- */
/* Utility function */
/* Return a viewing condition enumeration from the given Ambient and */
/* Adapting/Surround Luminance. */
static ViewingCondition cam02ref_Ambient2VC(
double La, /* Ambient Luminence (cd/m^2) */
double Lv /* Luminence of white in the Viewing/Scene/Image field (cd/m^2) */
) {
double r;
if (fabs(La) < 1e-10) /* Hmm. */
r = 1.0;
else
r = La/Lv;
if (r < 0.01)
return vc_dark;
if (r < 0.2)
return vc_dim;
return vc_average;
}
static void cam02ref_free(cam02ref *s);
static int cam02ref_set_view(cam02ref *s, ViewingCondition Ev, double Wxyz[3],
double Yb, double La, double Lv, double Yf, double Yg, double Gxyz[3],
int hk, double hkscale, double mtaf, double Wxyz2[3]);
static int cam02ref_XYZ_to_cam(cam02ref *s, double *Jab, double *xyz);
static int cam02ref_cam_to_XYZ(cam02ref *s, double XYZ[3], double Jab[3]);
/* Create a cam02 conversion object, with default viewing conditions */
cam02ref *new_cam02ref(void) {
cam02ref *s;
if ((s = (cam02ref *)malloc(sizeof(cam02ref))) == NULL) {
fprintf(stderr,"cam02: malloc failed allocating object\n");
exit(-1);
}
/* Initialise methods */
s->del = cam02ref_free;
s->set_view = cam02ref_set_view;
s->XYZ_to_cam = cam02ref_XYZ_to_cam;
s->cam_to_XYZ = cam02ref_cam_to_XYZ;
return s;
}
static void cam02ref_free(cam02ref *s) {
if (s != NULL)
free(s);
}
static int cam02ref_set_view(
cam02ref *s,
ViewingCondition Ev, /* Enumerated Viewing Condition */
double Wxyz[3], /* Reference/Adapted White XYZ (Y range 0.0 .. 1.0) */
double La, /* Adapting/Surround Luminance cd/m^2 */
double Yb, /* Relative Luminence of Background to reference white */
double Lv, /* Luminence of white in the Viewing/Scene/Image field (cd/m^2) */
/* Ignored if Ev is set to other than vc_none */
double Yf, /* Flare as a fraction of the reference white (Y range 0.0 .. 1.0) */
double Yg, /* Glare as a fraction of the adapting/surround (Y range 0.0 .. 1.0) */
double Gxyz[3], /* The Glare white coordinates (typically the Ambient color) */
int hk, /* Flag, NZ to use Helmholtz-Kohlraush effect */
double hkscale, /* HK effect scaling factor */
double mtaf, /* Mid tone partial adapation factor from Wxyz to Wxyz2, <= 0.0 if none */
double Wxyz2[3] /* Mid tone Adapted White XYZ (Y range 0.0 .. 1.0) */
) {
double tt;
if (Ev == vc_none) /* Compute enumerated viewing condition */
Ev = cam02ref_Ambient2VC(La, Lv);
/* Transfer parameters to the object */
s->Ev = Ev;
s->Wxyz[0] = Wxyz[0];
s->Wxyz[1] = Wxyz[1];
s->Wxyz[2] = Wxyz[2];
s->Yb = Yb > 0.005 ? Yb : 0.005; /* Set minimum to avoid divide by 0.0 */
s->La = La;
s->Yf = Yf;
if (Gxyz[0] > 0.0 && Gxyz[1] > 0.0 && Gxyz[2] > 0.0) {
tt = Wxyz[1]/Gxyz[1]; /* Scale to white ref white */
s->Gxyz[0] = tt * Gxyz[0];
s->Gxyz[1] = tt * Gxyz[1];
s->Gxyz[2] = tt * Gxyz[2];
} else {
s->Gxyz[0] = Wxyz[0];
s->Gxyz[1] = Wxyz[1];
s->Gxyz[2] = Wxyz[2];
}
s->hk = hk;
s->hkscale = hkscale;
/* Compute the internal parameters by category */
switch(s->Ev) {
case vc_dark:
s->C = 0.525;
s->Nc = 0.8;
s->F = 0.8;
Lv = La/0.033;
break;
case vc_dim:
s->C = 0.59;
s->Nc = 0.95;
s->F = 0.9;
Lv = La/0.1;
break;
case vc_average:
default: /* average */
s->C = 0.69;
s->Nc = 1.0;
s->F = 1.0;
Lv = La/0.2;
break;
case vc_cut_sheet:
s->C = 0.41;
s->Nc = 0.8;
s->F = 0.8;
Lv = La/0.02; // ???
break;
}
s->Lv = Lv;
/* Compute values that only change with viewing parameters */
/* Figure out the Flare contribution to the flareless XYZ input */
s->Fsxyz[0] = s->Yf * s->Wxyz[0];
s->Fsxyz[1] = s->Yf * s->Wxyz[1];
s->Fsxyz[2] = s->Yf * s->Wxyz[2];
/* Add in the Glare contribution from the adapting/surround */
tt = s->Yg * s->La/s->Lv;
s->Fsxyz[0] += tt * s->Gxyz[0];
s->Fsxyz[1] += tt * s->Gxyz[1];
s->Fsxyz[2] += tt * s->Gxyz[2];
/* Sharpened cone response white values */
s->rgbW[0] = 0.7328 * s->Wxyz[0] + 0.4296 * s->Wxyz[1] - 0.1624 * s->Wxyz[2];
s->rgbW[1] = -0.7036 * s->Wxyz[0] + 1.6975 * s->Wxyz[1] + 0.0061 * s->Wxyz[2];
s->rgbW[2] = 0.0000 * s->Wxyz[0] + 0.0000 * s->Wxyz[1] + 1.0000 * s->Wxyz[2];
/* Degree of chromatic adaption */
s->D = s->F * (1.0 - exp((-s->La - 42.0)/92.0)/3.6);
/* Precompute Chromatic transform values */
s->Drgb[0] = s->D * (s->Wxyz[1]/s->rgbW[0]) + 1.0 - s->D;
s->Drgb[1] = s->D * (s->Wxyz[1]/s->rgbW[1]) + 1.0 - s->D;
s->Drgb[2] = s->D * (s->Wxyz[1]/s->rgbW[2]) + 1.0 - s->D;
/* Chromaticaly transformed white value */
s->rgbcW[0] = s->Drgb[0] * s->rgbW[0];
s->rgbcW[1] = s->Drgb[1] * s->rgbW[1];
s->rgbcW[2] = s->Drgb[2] * s->rgbW[2];
/* Transform from spectrally sharpened, to Hunt-Pointer_Estevez cone space */
s->rgbpW[0] = 0.7409744840453773 * s->rgbcW[0]
+ 0.2180245944753982 * s->rgbcW[1]
+ 0.0410009214792244 * s->rgbcW[2];
s->rgbpW[1] = 0.2853532916858801 * s->rgbcW[0]
+ 0.6242015741188157 * s->rgbcW[1]
+ 0.0904451341953042 * s->rgbcW[2];
s->rgbpW[2] = -0.0096276087384294 * s->rgbcW[0]
- 0.0056980312161134 * s->rgbcW[1]
+ 1.0153256399545427 * s->rgbcW[2];
/* Background induction factor */
s->n = s->Yb/ s->Wxyz[1];
s->nn = pow(1.64 - pow(0.29, s->n), 0.73); /* Pre computed value */
/* Lightness contrast factor ?? */
{
double k;
k = 1.0 / (5.0 * s->La + 1.0);
s->Fl = 0.2 * pow(k , 4.0) * 5.0 * s->La
+ 0.1 * pow(1.0 - pow(k , 4.0) , 2.0) * pow(5.0 * s->La , 1.0/3.0);
}
/* Background and Chromatic brightness induction factors */
s->Nbb = 0.725 * pow(1.0/s->n, 0.2);
s->Ncb = s->Nbb;
/* Base exponential nonlinearity */
s->z = 1.48 + pow(s->n , 0.5);
/* Post-adapted cone response of white */
tt = pow(s->Fl * s->rgbpW[0], 0.42);
s->rgbaW[0] = (400.1 * tt + 2.713) / (tt + 27.13);
tt = pow(s->Fl * s->rgbpW[1], 0.42);
s->rgbaW[1] = (400.1 * tt + 2.713) / (tt + 27.13);
tt = pow(s->Fl * s->rgbpW[2], 0.42);
s->rgbaW[2] = (400.1 * tt + 2.713) / (tt + 27.13);
/* Achromatic response of white */
s->Aw = (2.0 * s->rgbaW[0] + s->rgbaW[1] + (1.0/20.0) * s->rgbaW[2] - 0.305) * s->Nbb;
#ifdef DIAG
printf("Ref. Scene parameters:\n");
printf("Viewing condition Ev = %d\n",s->Ev);
printf("Ref white Wxyz = %f %f %f\n", s->Wxyz[0], s->Wxyz[1], s->Wxyz[2]);
printf("Relative liminance of background Yb = %f\n", s->Yb);
printf("Adapting liminance La = %f\n", s->La);
printf("Flare Yf = %f\n", s->Yf);
printf("Flare color Fxyz = %f %f %f\n", s->Fxyz[0], s->Fxyz[1], s->Fxyz[2]);
printf("Internal parameters:\n");
printf("Surround Impact C = %f\n", s->C);
printf("Chromatic Induction Nc = %f\n", s->Nc);
printf("Adaption Degree F = %f\n", s->F);
printf("Pre-computed values\n");
printf("Sharpened cone white rgbW = %f %f %f\n", s->rgbW[0], s->rgbW[1], s->rgbW[2]);
printf("Degree of chromatic adaption D = %f\n", s->D);
printf("Chromatic transform values Drgb = %f %f %f\n", s->Drgb[0], s->Drgb[1], s->Drgb[2]);
printf("Chromatically transformed white rgbcW = %f %f %f\n", s->rgbcW[0], s->rgbcW[1], s->rgbcW[2]);
printf("Hunter-P-E cone response white rgbpW = %f %f %f\n", s->rgbpW[0], s->rgbpW[1], s->rgbpW[2]);
printf("Background induction factor n = %f\n", s->n);
printf("Lightness contrast factor Fl = %f\n", s->Fl);
printf("Background brightness induction factor Nbb = %f\n", s->Nbb);
printf("Chromatic brightness induction factor Ncb = %f\n", s->Ncb);
printf("Base exponential nonlinearity z = %f\n", s->z);
printf("Post adapted cone response white rgbaW = %f %f %f\n", s->rgbaW[0], s->rgbaW[1], s->rgbaW[2]);
printf("Achromatic response of white Aw = %f\n", s->Aw);
printf("\n");
#endif
return 0;
}
/* A version of the pow() function that preserves the */
/* sign of its first argument. */
static double spow(double x, double y) {
return x < 0.0 ? -pow(-x,y) : pow(x,y);
}
#define REFTRACE(xxxx) if (s->trace) printf xxxx ;
/* Conversion. Returns NZ and -1, -1, -1 if input is out of range */
static int cam02ref_XYZ_to_cam(
cam02ref *s,
double Jab[3],
double XYZ[3]
) {
int i;
double xyz[3], rgb[3], rgbp[3], rgba[3], rgbaW[3], rgbc[3], rgbcW[3];
double a, b, rS, J, C, h, e, A, ss;
double ttd, tt;
REFTRACE(("\nReference forward conversion:\n"))
REFTRACE(("XYZ %f %f %f\n",XYZ[0], XYZ[1], XYZ[2]))
/* Add in flare */
xyz[0] = s->Fsc * XYZ[0] + s->Fsxyz[0];
xyz[1] = s->Fsc * XYZ[1] + s->Fsxyz[1];
xyz[2] = s->Fsc * XYZ[2] + s->Fsxyz[2];
REFTRACE(("Including flare XYZ = %f %f %f\n", xyz[0], xyz[1], xyz[2]))
/* Spectrally sharpened cone responses */
rgb[0] = 0.7328 * xyz[0] + 0.4296 * xyz[1] - 0.1624 * xyz[2];
rgb[1] = -0.7036 * xyz[0] + 1.6975 * xyz[1] + 0.0061 * xyz[2];
rgb[2] = 0.0000 * xyz[0] + 0.0000 * xyz[1] + 1.0000 * xyz[2];
REFTRACE(("Sharpened cone sample rgb = %f %f %f\n", rgb[0], rgb[1], rgb[2]))
/* Chromaticaly transformed sample value */
rgbc[0] = s->Drgb[0] * rgb[0];
rgbc[1] = s->Drgb[1] * rgb[1];
rgbc[2] = s->Drgb[2] * rgb[2];
REFTRACE(("Chromatically transformed sample value rgbc = %f %f %f\n", rgb[0], rgb[1], rgb[2]))
/* Transform from spectrally sharpened, to Hunt-Pointer_Estevez cone space */
rgbp[0] = 0.7409744840453773 * rgbc[0]
+ 0.2180245944753982 * rgbc[1]
+ 0.0410009214792244 * rgbc[2];
rgbp[1] = 0.2853532916858801 * rgbc[0]
+ 0.6242015741188157 * rgbc[1]
+ 0.0904451341953042 * rgbc[2];
rgbp[2] = -0.0096276087384294 * rgbc[0]
- 0.0056980312161134 * rgbc[1]
+ 1.0153256399545427 * rgbc[2];
REFTRACE(("rgbp = %f %f %f\n", rgbp[0], rgbp[1], rgbp[2]))
/* Post-adapted cone response of sample. */
/* rgba[] has a minimum value of 0.1 for XYZ[] = 0 and no flare. */
/* We add a symetric negative compression region */
for (i = 0; i < 3; i++) {
if (s->range && (rgbp[i] < 0.0 || rgbp[i] < s->nldlimit)) {
Jab[0] = Jab[1] = Jab[2] = -1.0;
return 1;
}
if (rgbp[i] < 0.0) {
tt = pow(s->Fl * -rgbp[i], 0.42);
rgba[i] = (2.713 - 397.387 * tt) / (tt + 27.13);
} else {
tt = pow(s->Fl * rgbp[i], 0.42);
rgba[i] = (400.1 * tt + 2.713) / (tt + 27.13);
}
}
REFTRACE(("rgba = %f %f %f\n", rgba[0], rgba[1], rgba[2]))
/* Preliminary red-green & yellow-blue opponent dimensions */
a = rgba[0] - 12.0 * rgba[1]/11.0 + rgba[2]/11.0;
b = (1.0/9.0) * (rgba[0] + rgba[1] - 2.0 * rgba[2]);
rS = sqrt(a * a + b * b); /* Normalised a, b */
/* Preliminary Saturation */
/* Note that the minimum values for rgba[] for XYZ = 0 is 0.1 */
/* Hence magic 0.305 below comes from the following weighting of rgba[] */
ttd = rgba[0] + rgba[1] + (21.0/20.0) * rgba[2];
/* Achromatic response */
/* Note that the minimum values of rgba[] for XYZ = 0 is 0.1, */
/* hence magic 0.305 below comes from the following weighting of rgba[], */
/* to base A at 0.0 */
A = (2.0 * rgba[0] + rgba[1] + (1.0/20.0) * rgba[2] - 0.305) * s->Nbb;
REFTRACE(("a = %f, b = %f, ttd = %f, rS = %f, A = %f\n", a, b, ttd, rS, A))
/* Lightness */
J = pow(A/s->Aw, s->C * s->z); /* J/100 - keep Sign */
/* Hue angle */
h = (180.0/DBL_PI) * atan2(b,a);
h = (h < 0.0) ? h + 360.0 : h;
/* Eccentricity factor */
e = (cos(h * DBL_PI/180.0 + 2.0) + 3.8);
if (s->range && (J < DBL_EPSILON || J < s->jlimit || ttd < DBL_EPSILON)) {
REFTRACE(("J = %f, ttd = %f, exit with error\n", J, ttd))
Jab[0] = Jab[1] = Jab[2] = -1.0;
return 1;
}
ss = (12500.0/13.0 * s->Nc * s->Ncb * rS * e) / ttd;
/* Chroma */
C = pow(ss, 0.9) * sqrt(J) * s->nn;
REFTRACE(("ss = %f, C = %f\n", ss, C))
/* Helmholtz-Kohlraush effect */
if (s->hk && J < 1.0) {
double JJ, kk = s->hkscale * HHKR_MUL * C/300.0 * sin(DBL_PI * fabs(0.5 * (h - 90.0))/180.0);
if (kk > 0.9) /* Limit kk to a reasonable range */
kk = 0.9;
JJ = J + (1.0 - J) * kk;
REFTRACE(("JJ = %f from J = %f, kk = %f\n",JJ,J,kk))
J = JJ;
}
J *= 100.0; /* Scale J */
/* Compute Jab value */
Jab[0] = J;
if (rS >= DBL_EPSILON) {
Jab[1] = C * a/rS;
Jab[2] = C * b/rS;
} else {
Jab[1] = 0.0;
Jab[2] = 0.0;
}
REFTRACE(("Returning Jab %f %f %f\n", Jab[0],Jab[1],Jab[2]))
#ifdef DIAG
printf("Processing:\n");
printf("XYZ = %f %f %f\n", XYZ[0], XYZ[1], XYZ[2]);
printf("Including flare XYZ = %f %f %f\n", xyz[0], xyz[1], xyz[2]);
printf("Sharpened cone sample rgb = %f %f %f\n", rgb[0], rgb[1], rgb[2]);
printf("Chromatically transformed sample value rgbc = %f %f %f\n", rgbc[0], rgbc[1], rgbc[2]);
printf("Hunt-P-E cone space rgbp = %f %f %f\n", rgbp[0], rgbp[1], rgbp[2]);
printf("Post adapted cone response rgba = %f %f %f\n", rgba[0], rgba[1], rgba[2]);
printf("Prelim red green a = %f, b = %f\n", a, b);
printf("Hue angle h = %f\n", h);
printf("Eccentricity factor e = %f\n", e);
printf("Achromatic response A = %f\n", A);
printf("Lightness J = %f\n", J);
printf("Prelim Saturation ss = %f\n", ss);
printf("Chroma C = %f\n", C);
printf("Jab = %f %f %f\n", Jab[0], Jab[1], Jab[2]);
printf("\n");
#endif
return 0;
}
static int cam02ref_cam_to_XYZ(
cam02ref *s,
double XYZ[3],
double Jab[3]
) {
int i;
double xyz[3], rgb[3], rgbp[3], rgba[3], rgbaW[3], rgbc[3], rgbcW[3];
double ja, jb, aa, ab, a, b, J, C, h, e, A, ss;
double tt, ttA, tte;
J = Jab[0] * 0.01; /* J/100 */
ja = Jab[1];
jb = Jab[2];
/* Compute hue angle */
h = (180.0/DBL_PI) * atan2(jb, ja);
h = (h < 0.0) ? h + 360.0 : h;
/* Compute chroma value */
C = sqrt(ja * ja + jb * jb); /* Must be Always +ve */
/* Helmholtz-Kohlraush effect */
if (s->hk && J < 1.0) {
double kk = s->hkscale * HHKR_MUL * C/300.0 * sin(DBL_PI * fabs(0.5 * (h - 90.0))/180.0);
if (kk > 0.9) /* Limit kk to a reasonable range */
kk = 0.9;
J = (J - kk)/(1.0 - kk);
}
/* Eccentricity factor */
e = (cos(h * DBL_PI/180.0 + 2.0) + 3.8);
/* Achromatic response */
A = spow(J, 1.0/(s->C * s->z)) * s->Aw; /* Keep sign of J */
/* Preliminary Saturation - keep +ve */
tt = fabs(J);
ss = pow(C/(sqrt(tt) * s->nn), 1.0/0.9); /* keep +ve */
/* Compute a & b, taking care of numerical problems */
aa = fabs(ja);
ab = fabs(jb);
ttA = (A/s->Nbb)+0.305; /* Common factor */
tte = 12500.0/13.0 * e * s->Nc * s->Ncb; /* Common factor */
if (aa < 1e-10 && ab < 1e-10) {
a = ja;
b = jb;
} else if (aa > ab) {
double tanh = jb/ja;
double sign = (h > 90.0 && h <= 270.0) ? -1.0 : 1.0;
if (ttA < 0.0)
sign = -sign;
a = (ss * ttA)
/ (sign * sqrt(1.0 + tanh * tanh) * tte + (ss * (11.0/23.0 + (108.0/23.0) * tanh)));
b = a * tanh;
} else { /* ab > aa */
double itanh = ja/jb;
double sign = (h > 180.0 && h <= 360.0) ? -1.0 : 1.0;
if (ttA < 0.0)
sign = -sign;
b = (ss * ttA)
/ (sign * sqrt(1.0 + itanh * itanh) * tte + (ss * (108.0/23.0 + (11.0/23.0) * itanh)));
a = b * itanh;
}
/* Post-adapted cone response of sample */
rgba[0] = (20.0/61.0) * ttA
+ ((41.0 * 11.0)/(61.0 * 23.0)) * a
+ ((288.0 * 1.0)/(61.0 * 23.0)) * b;
rgba[1] = (20.0/61.0) * ttA
- ((81.0 * 11.0)/(61.0 * 23.0)) * a
- ((261.0 * 1.0)/(61.0 * 23.0)) * b;
rgba[2] = (20.0/61.0) * ttA
- ((20.0 * 11.0)/(61.0 * 23.0)) * a
- ((20.0 * 315.0)/(61.0 * 23.0)) * b;
/* Hunt-Pointer_Estevez cone space */
tt = 1.0/s->Fl;
for (i = 0; i < 3; i++) {
if (rgba[i] < 0.1) {
double ta = rgba[i] > -396.387 ? rgba[i] : -396.387;
rgbp[i] = -tt * pow((2.713 - 27.13 * rgba[i] )/(397.387 + ta), 1.0/0.42);
} else {
double ta = rgba[i] < 399.1 ? rgba[i] : 399.1;
rgbp[i] = tt * pow((27.13 * rgba[i] -2.713)/(400.1 - ta), 1.0/0.42);
}
}
/* Chromaticaly transformed sample value */
rgbc[0] = 1.5591523979049677 * rgbp[0]
- 0.5447226796590880 * rgbp[1]
- 0.0144453097698588 * rgbp[2];
rgbc[1] = -0.7143267176368630 * rgbp[0]
+ 1.8503099728895096 * rgbp[1]
- 0.1359761119854705 * rgbp[2];
rgbc[2] = 0.0107755117023383 * rgbp[0]
+ 0.0052187662221759 * rgbp[1]
+ 0.9840056143203700 * rgbp[2];
/* Spectrally sharpened cone responses */
rgb[0] = rgbc[0]/s->Drgb[0];
rgb[1] = rgbc[1]/s->Drgb[1];
rgb[2] = rgbc[2]/s->Drgb[2];
/* XYZ values */
xyz[0] = 1.0961238208355140 * rgb[0]
- 0.2788690002182872 * rgb[1]
+ 0.1827451793827730 * rgb[2];
xyz[1] = 0.4543690419753590 * rgb[0]
+ 0.4735331543074120 * rgb[1]
+ 0.0720978037172291 * rgb[2];
xyz[2] = -0.0096276087384294 * rgb[0]
- 0.0056980312161134 * rgb[1]
+ 1.0153256399545427 * rgb[2];
/* Subtract flare */
XYZ[0] = s->Fisc * (xyz[0] - s->Fsxyz[0]);
XYZ[1] = s->Fisc * (xyz[1] - s->Fsxyz[1]);
XYZ[2] = s->Fisc * (xyz[2] - s->Fsxyz[2]);
#ifdef DIAG
printf("Processing:\n");
printf("Jab = %f %f %f\n", Jab[0], Jab[1], Jab[2]);
printf("Chroma C = %f\n", C);
printf("Preliminary Saturation ss = %f\n", ss);
printf("Lightness J = %f\n", J * 100.0);
printf("Achromatic response A = %f\n", A);
printf("Eccentricity factor e = %f\n", e);
printf("Hue angle h = %f\n", h);
printf("Prelim red green a = %f, b = %f\n", a, b);
printf("Post adapted cone response rgba = %f %f %f\n", rgba[0], rgba[1], rgba[2]);
printf("Hunt-P-E cone space rgbp = %f %f %f\n", rgbp[0], rgbp[1], rgbp[2]);
printf("Chromatically transformed sample value rgbc = %f %f %f\n", rgbc[0], rgbc[1], rgbc[2]);
printf("Sharpened cone sample rgb = %f %f %f\n", rgb[0], rgb[1], rgb[2]);
printf("Including flare XYZ = %f %f %f\n", xyz[0], xyz[1], xyz[2]);
printf("XYZ = %f %f %f\n", XYZ[0], XYZ[1], XYZ[2]);
printf("\n");
#endif
return 0;
}
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