private static Color XyzToRgb(XyzColor color)
{
// Convert from XYZ to RGB.
// Algorithm from https://www.easyrgb.com/en/math.php
double tempX = color.X / 100.0;
double tempY = color.Y / 100.0;
double tempZ = color.Z / 100.0;
double r = tempX * 3.2406 + tempY * -1.5372 + tempZ * -0.4986;
double g = tempX * -0.9689 + tempY * 1.8758 + tempZ * 0.0415;
double b = tempX * 0.0557 + tempY * -0.2040 + tempZ * 1.0570;
r = r > 0.0031308 ? 1.055 * Math.Pow(r, 1 / 2.4) - 0.055 : 12.92 * r;
g = g > 0.0031308 ? 1.055 * Math.Pow(g, 1 / 2.4) - 0.055 : 12.92 * g;
b = b > 0.0031308 ? 1.055 * Math.Pow(b, 1 / 2.4) - 0.055 : 12.92 * b;
r *= 255.0;
g *= 255.0;
b *= 255.0;
return(Color.FromArgb((byte)r, (byte)g, (byte)b));
}
private static LabColor XyzToLab(XyzColor color)
{
// Convert from XYZ to LAB.
// Algorithm from https://www.easyrgb.com/en/math.php
// Using D65 observer values
double x = color.X;
double y = color.Y;
double z = color.Z;
x /= referenceX;
y /= referenceY;
z /= referenceZ;
x = x > 0.008856 ? Math.Pow(x, 1 / 3.0) : (7.787 * x) + (16 / 116.0);
y = y > 0.008856 ? Math.Pow(y, 1 / 3.0) : (7.787 * y) + (16 / 116.0);
z = z > 0.008856 ? Math.Pow(z, 1 / 3.0) : (7.787 * z) + (16 / 116.0);
double l = (116 * y) - 16;
double a = 500 * (x - y);
double b = 200 * (y - z);
return(new LabColor(l, a, b));
}
public static LabColor FromXyz(XyzColor color)
{
return(FromXyz(color.X, color.Y, color.Z));
}
public static LabColor FromRgb(Color color)
{
return(XyzToLab(XyzColor.FromRgb(color)));
}