public static Color SetLightness(Color color, float brightness)
{
ColorHSL hsl = RGBtoHSL(color);
hsl.L = brightness;
return(HSLtoRGB(hsl));
}
public static void SetLightness(ref Color color, float brightness)
{
ColorHSL hsl = RGBtoHSL(color);
hsl.L = brightness;
color = HSLtoRGB(hsl);
}
/// <summary>
/// Converts a Color from RGB to HSL
/// See http://en.wikipedia.org/wiki/HSL_color_space#Conversion_from_RGB_to_HSL_or_HSV for details
/// </summary>
/// <param name="color"></param>
/// <returns></returns>
public static ColorHSL RGBtoHSL(Color color)
{
ColorHSL hsl = new ColorHSL();
float R = (float)color.R / (float)byte.MaxValue;
float G = (float)color.G / (float)byte.MaxValue;
float B = (float)color.B / (float)byte.MaxValue;
float min = Math.Min(R, G);
min = Math.Min(min, B);
float max = Math.Max(R, G);
max = Math.Max(max, B);
hsl.L = (max + min) / 2;
if (hsl.L < 0.5f)
{
hsl.S = (max - min) / (max + min);
}
else if (hsl.L >= 0.5f)
{
hsl.S = (max - min) / (2.0f - max - min);
}
if (max == min)
{
hsl.S = 0;
}
if (R == max)
{
hsl.H = (G - B) / (max - min);
}
else if (G == max)
{
hsl.H = 2.0f + (B - R) / (max - min);
}
else if (B == max)
{
hsl.H = 4.0f + (R - G) / (max - min);
}
hsl.H *= 360;
return(hsl);
}
/// <summary>
/// Converts a Color from HSL to RGB
/// See http://en.wikipedia.org/wiki/HSL_color_space#Conversion_from_HSL_to_RGB for details
/// </summary>
/// <param name="hsl"></param>
/// <returns></returns>
public static Color HSLtoRGB(ColorHSL hsl)
{
if (hsl.S == 0)
{
return(new Color(hsl.L, hsl.L, hsl.L));
}
float temp1;
float temp2;
float Rtemp3, Gtemp3, Btemp3;
float H;
if (hsl.L < 0.5f)
{
temp2 = hsl.L * (1.0f + hsl.S);
}
else
{
temp2 = hsl.L + hsl.S - hsl.L * hsl.S;
}
temp1 = 2.0f * hsl.L - temp2;
H = hsl.H / 360;
Rtemp3 = H + 1.0f / 3.0f;
Gtemp3 = H;
Btemp3 = H - 1.0f / 3.0f;
if (Rtemp3 < 0)
{
Rtemp3 += 1.0f;
}
if (Rtemp3 > 1)
{
Rtemp3 -= 1.0f;
}
if (Gtemp3 < 0)
{
Gtemp3 += 1.0f;
}
if (Gtemp3 > 1)
{
Gtemp3 -= 1.0f;
}
if (Btemp3 < 0)
{
Btemp3 += 1.0f;
}
if (Btemp3 > 1)
{
Btemp3 -= 1.0f;
}
float R, G, B;
if ((6.0f * Rtemp3) < 1)
{
R = temp1 + (temp2 - temp1) * 6.0f * Rtemp3;
}
else if (2.0f * Rtemp3 < 1)
{
R = temp2;
}
else if (3.0f * Rtemp3 < 2)
{
R = temp1 + (temp2 - temp1) * ((2.0f / 3.0f) - Rtemp3) * 6.0f;
}
else
{
R = temp1;
}
if ((6.0f * Gtemp3) < 1)
{
G = temp1 + (temp2 - temp1) * 6.0f * Gtemp3;
}
else if (2.0f * Gtemp3 < 1)
{
G = temp2;
}
else if (3.0f * Gtemp3 < 2)
{
G = temp1 + (temp2 - temp1) * ((2.0f / 3.0f) - Gtemp3) * 6.0f;
}
else
{
G = temp1;
}
if ((6.0f * Btemp3) < 1)
{
B = temp1 + (temp2 - temp1) * 6.0f * Btemp3;
}
else if (2.0f * Btemp3 < 1)
{
B = temp2;
}
else if (3.0f * Btemp3 < 2)
{
B = temp1 + (temp2 - temp1) * ((2.0f / 3.0f) - Btemp3) * 6.0f;
}
else
{
B = temp1;
}
return(new Color(R, G, B));
}
