/// <summary>
/// Returns the correct matrix to convert between the Rgb and CieXyz color space.
/// </summary>
/// <param name="workingSpace">The Rgb working space.</param>
/// <returns>The <see cref="Matrix4x4"/> based on the chromaticity and working space.</returns>
public static Matrix4x4 GetRgbToCieXyzMatrix(RgbWorkingSpace workingSpace)
{
DebugGuard.NotNull(workingSpace, nameof(workingSpace));
RgbPrimariesChromaticityCoordinates chromaticity = workingSpace.ChromaticityCoordinates;
float xr = chromaticity.R.X;
float xg = chromaticity.G.X;
float xb = chromaticity.B.X;
float yr = chromaticity.R.Y;
float yg = chromaticity.G.Y;
float yb = chromaticity.B.Y;
float mXr = xr / yr;
const float Yr = 1;
float mZr = (1 - xr - yr) / yr;
float mXg = xg / yg;
const float Yg = 1;
float mZg = (1 - xg - yg) / yg;
float mXb = xb / yb;
const float Yb = 1;
float mZb = (1 - xb - yb) / yb;
var xyzMatrix = new Matrix4x4
{
M11 = mXr,
M21 = mXg,
M31 = mXb,
M12 = Yr,
M22 = Yg,
M32 = Yb,
M13 = mZr,
M23 = mZg,
M33 = mZb,
M44 = 1F
};
Matrix4x4.Invert(xyzMatrix, out Matrix4x4 inverseXyzMatrix);
var vector = Vector3.Transform(workingSpace.WhitePoint.ToVector3(), inverseXyzMatrix);
// Use transposed Rows/Columns
// TODO: Is there a built in method for this multiplication?
return(new Matrix4x4
{
M11 = vector.X * mXr,
M21 = vector.Y * mXg,
M31 = vector.Z * mXb,
M12 = vector.X * Yr,
M22 = vector.Y * Yg,
M32 = vector.Z * Yb,
M13 = vector.X * mZr,
M23 = vector.Y * mZg,
M33 = vector.Z * mZb,
M44 = 1F
});
}
/// <summary>
/// Initializes a new instance of the <see cref="CieXyzToLinearRgbConverter"/> class.
/// </summary>
/// <param name="workingSpace">The target working space.</param>
public CieXyzToLinearRgbConverter(RgbWorkingSpace workingSpace)
{
this.TargetWorkingSpace = workingSpace;
// Gets the inverted Rgb -> Xyz matrix
Matrix4x4.Invert(GetRgbToCieXyzMatrix(workingSpace), out Matrix4x4 inverted);
this.conversionMatrix = inverted;
}
/// <summary>
/// Initializes a new instance of the <see cref="LinearRgbToCieXyzConverter"/> class.
/// </summary>
/// <param name="workingSpace">The target working space.</param>
public LinearRgbToCieXyzConverter(RgbWorkingSpace workingSpace)
{
this.SourceWorkingSpace = workingSpace;
this.conversionMatrix = GetRgbToCieXyzMatrix(workingSpace);
}
