public static Color HsbToRgb(HsbColor hsbColor)
{
/* Gray (zero saturation) is a special case.We simply
* set RGB values to HSB Brightness value and exit. */
// Gray: Set RGB and return
if (hsbColor.S == 0.0)
{
return(Color.FromArgb((byte)(hsbColor.A * 255),
(byte)(hsbColor.B * 255),
(byte)(hsbColor.B * 255),
(byte)(hsbColor.B * 255)
));
}
/* Now we process the normal case. */
var h = (hsbColor.H == 360) ? 0 : hsbColor.H / 60;
//var i = (int)(Math.Truncate(h));
//var i = (int)(Math.Round(h));
if (double.IsNaN(h))
{
return(Color.FromArgb((byte)(hsbColor.A * 255),
(byte)(hsbColor.B * 255),
(byte)(hsbColor.B * 255),
(byte)(hsbColor.B * 255)
));
}
int i = Convert.ToInt32(Math.Floor(h));
var f = h - i;
var p = hsbColor.B * (1.0 - hsbColor.S);
var q = hsbColor.B * (1.0 - (hsbColor.S * f));
var t = hsbColor.B * (1.0 - (hsbColor.S * (1.0 - f)));
double r, g, b;
switch (i)
{
case 0:
r = hsbColor.B;
g = t;
b = p;
break;
case 1:
r = q;
g = hsbColor.B;
b = p;
break;
case 2:
r = p;
g = hsbColor.B;
b = t;
break;
case 3:
r = p;
g = q;
b = hsbColor.B;
break;
case 4:
r = t;
g = p;
b = hsbColor.B;
break;
default:
r = hsbColor.B;
g = p;
b = q;
break;
}
// Set return value
return(Color.FromArgb((byte)(hsbColor.A * 255),
(byte)(r * 255),
(byte)(g * 255),
(byte)(b * 255)
));
}
public static HsbColor RgbToHsb(Color rgbColor)
{
/* Hue values range between 0 and 360. All
* other values range between 0 and 1. */
// Create HSB color object
var hsbColor = new HsbColor();
// Get RGB color component values
var r = (int)rgbColor.R;
var g = (int)rgbColor.G;
var b = (int)rgbColor.B;
var a = (int)rgbColor.A;
// Get min, max, and delta values
double min = Math.Min(Math.Min(r, g), b);
double max = Math.Max(Math.Max(r, g), b);
double delta = max - min;
/* Black (max = 0) is a special case. We
* simply set HSB values to zero and exit. */
// Black: Set HSB and return
if (max == 0.0)
{
hsbColor.H = 0.0;
hsbColor.S = 0.0;
hsbColor.B = 0.0;
hsbColor.A = a / 255;
return(hsbColor);
}
/* Now we process the normal case. */
// Set HSB Alpha value
var alpha = (double)a;
hsbColor.A = alpha / 255;
// Set HSB Hue value
if (r == max)
{
hsbColor.H = (g - b) / delta;
}
else if (g == max)
{
hsbColor.H = 2 + (b - r) / delta;
}
else if (b == max)
{
hsbColor.H = 4 + (r - g) / delta;
}
hsbColor.H *= 60;
if (hsbColor.H < 0.0)
{
hsbColor.H += 360;
}
// Set other HSB values
hsbColor.S = delta / max;
hsbColor.B = max / 255;
// Set return value
return(hsbColor);
}