private static byte ColorAngle(ColorBgra color, ColorBgra filter)
{
if (color == filter)
{
return(0);
}
Vector3D filterVector = filter.ToVector3D();
Vector3D colorVector = color.ToVector3D();
double scale = 2 * Vector3D.VectorAngle(colorVector, filterVector) / Math.PI;
return(Utility.ClampToByte(scale * 255));
}