public static RGBColor xyz2rgb(XYZColor xyz)
{
//X from 0 to 95.047 (Observer = 2°, Illuminant = D65)
//Y from 0 to 100.000
//Z from 0 to 108.883
double x = xyz.x / 100.0;
double y = xyz.y / 100.0;
double z = xyz.z / 100.0;
/*
* double r = x * 3.2406 + y * -1.5372 + z * -0.4986;
* double g = x * -0.9689 + y * 1.8758 + z * 0.0415;
* double b = x * 0.0557 + y * -0.2040 + z * 1.0570;
*/
double r = x * 3.2404542 + y * -1.5371385 + z * -0.4985314;
double g = x * -0.9692660 + y * 1.8760108 + z * 0.0415560;
double b = x * 0.0556434 + y * -0.2040259 + z * 1.0572252;
if (r > 0.0031308)
{
r = 1.055 * Math.Pow(r, (1 / 2.4)) - 0.055;
}
else
{
r = 12.92 * r;
}
if (g > 0.0031308)
{
g = 1.055 * Math.Pow(g, (1 / 2.4)) - 0.055;
}
else
{
g = 12.92 * g;
}
if (b > 0.0031308)
{
b = 1.055 * Math.Pow(b, (1 / 2.4)) - 0.055;
}
else
{
b = 12.92 * b;
}
RGBColor rgb = new RGBColor(0, 0, 0);
rgb.r = (int)Math.Round(r * 255);
rgb.g = (int)Math.Round(g * 255);
rgb.b = (int)Math.Round(b * 255);
return(rgb);
}
public static XYZColor rgb2xyz(RGBColor rgb)
{
double r = rgb.r / 255.0;
double g = rgb.g / 255.0;
double b = rgb.b / 255.0;
if (r > 0.04045)
{
r = Math.Pow((r + 0.055) / 1.055, 2.4);
}
else
{
r = r / 12.92;
}
if (g > 0.04045)
{
g = Math.Pow((g + 0.055) / 1.055, 2.4);
}
else
{
g = g / 12.92;
}
if (b > 0.04045)
{
b = Math.Pow((b + 0.055) / 1.055, 2.4);
}
else
{
b = b / 12.92;
}
r = r * 100;
g = g * 100;
b = b * 100;
//Observer. = 2°, Illuminant = D65
XYZColor xyz = new XYZColor(0, 0, 0);
/*
* xyz.x = r * 0.4124 + g * 0.3576 + b * 0.1805;
* xyz.y = r * 0.2126 + g * 0.7152 + b * 0.0722;
* xyz.z = r * 0.0193 + g * 0.1192 + b * 0.9505;
*/
xyz.x = r * 0.4124564 + g * 0.3575761 + b * 0.1804375;
xyz.y = r * 0.2126729 + g * 0.7151522 + b * 0.0721750;
xyz.z = r * 0.0193339 + g * 0.1191920 + b * 0.9503041;
return(xyz);
}
public static XYZColor lab2xyz(LabColor lab)
{
const double REF_X = 95.047; // Observer= 2°, Illuminant= D65
const double REF_Y = 100.000;
const double REF_Z = 108.883;
double y = (lab.l + 16.0) / 116.0;
double x = lab.a / 500.0 + y;
double z = y - lab.b / 200.0;
if (Math.Pow(y, 3) > 0.008856)
{
y = Math.Pow(y, 3);
}
else
{
y = (y - 16.0 / 116.0) / 7.787;
}
if (Math.Pow(x, 3) > 0.008856)
{
x = Math.Pow(x, 3);
}
else
{
x = (x - 16.0 / 116.0) / 7.787;
}
if (Math.Pow(z, 3) > 0.008856)
{
z = Math.Pow(z, 3);
}
else
{
z = (z - 16.0 / 116.0) / 7.787;
}
XYZColor xyz = new XYZColor(0, 0, 0);
xyz.x = REF_X * x;
xyz.y = REF_Y * y;
xyz.z = REF_Z * z;
return(xyz);
}
public static LabColor xyz2lab(XYZColor xyz)
{
const double REF_X = 95.047; // Observer= 2°, Illuminant= D65
const double REF_Y = 100.000;
const double REF_Z = 108.883;
double x = xyz.x / REF_X;
double y = xyz.y / REF_Y;
double z = xyz.z / REF_Z;
if (x > 0.008856)
{
x = Math.Pow(x, 1.0 / 3.0);
}
else
{
x = (7.787 * x) + (16.0 / 116.0);
}
if (y > 0.008856)
{
y = Math.Pow(y, 1.0 / 3.0);
}
else
{
y = (7.787 * y) + (16.0 / 116.0);
}
if (z > 0.008856)
{
z = Math.Pow(z, 1.0 / 3.0);
}
else
{
z = (7.787 * z) + (16.0 / 116.0);
}
LabColor lab = new LabColor(0, 0, 0);
lab.l = (int)(116 * y) - 16;
lab.a = (int)(500 * (x - y));
lab.b = (int)(200 * (y - z));
return(lab);
}
public static RGBColor lab2rgb(LabColor lab)
{
XYZColor xyz = ColorConversor.lab2xyz(lab);
return(ColorConversor.xyz2rgb(xyz));
}
public static LabColor rgb2lab(RGBColor rgb)
{
XYZColor xyz = ColorConversor.rgb2xyz(rgb);
return(ColorConversor.xyz2lab(xyz));
}
