public static float GetHue(this Color color)
{
int r = color.R;
int g = color.G;
int b = color.B;
byte minval = (byte)Math.Min(r, Math.Min(g, b));
byte maxval = (byte)Math.Max(r, Math.Max(g, b));
if (maxval == minval)
return 0.0f;
float diff = (float)(maxval - minval);
float rnorm = (maxval - r) / diff;
float gnorm = (maxval - g) / diff;
float bnorm = (maxval - b) / diff;
float hue = 0.0f;
if (r == maxval)
hue = 60.0f * (6.0f + bnorm - gnorm);
if (g == maxval)
hue = 60.0f * (2.0f + rnorm - bnorm);
if (b == maxval)
hue = 60.0f * (4.0f + gnorm - rnorm);
if (hue > 360.0f)
hue = hue - 360.0f;
return hue;
}