public static CIELab ToCIELab(
this CIEAXYZ axyz
)
{
CIELab lab = CIELab.Empty;
double x = axyz.X;
double y = axyz.Y;
double z = axyz.Z;
lab.Luminance = 116.0 * Fxyz(y / CIEAXYZ.D65.Y) - 16;
lab.RedGreenDimension = 500.0 * (Fxyz(x / CIEAXYZ.D65.X) - Fxyz(y / CIEAXYZ.D65.Y));
lab.YellowBlueDimension = 200.0 * (Fxyz(y / CIEAXYZ.D65.Y) - Fxyz(z / CIEAXYZ.D65.Z));
lab.Alpha = axyz.Alpha;
return(lab);
}
public static CIEAXYZ ToCIEAXYZ(
this CIELab lab
)
{
double l = lab.Luminance;
double a = lab.RedGreenDimension;
double b = lab.YellowBlueDimension;
double delta = 6.0 / 29.0;
double fy = (l + 16) / 116.0;
double fx = fy + (a / 500.0);
double fz = fy - (b / 200.0);
return(new CIEAXYZ(
lab.Alpha,
(fx > delta) ? CIEAXYZ.D65.X * (fx * fx * fx) : (fx - 16.0 / 116.0) * 3 * (delta * delta) * CIEAXYZ.D65.X,
(fy > delta) ? CIEAXYZ.D65.Y * (fy * fy * fy) : (fy - 16.0 / 116.0) * 3 * (delta * delta) * CIEAXYZ.D65.Y,
(fz > delta) ? CIEAXYZ.D65.Z * (fz * fz * fz) : (fz - 16.0 / 116.0) * 3 * (delta * delta) * CIEAXYZ.D65.Z));
}
public static DoubleColor Double(
this CIELab lab
)
{
return(lab.ToCIEAXYZ().Double());
}