// http://www.rapidtables.com/convert/color/hsl-to-rgb.htm
public static ColorRgb hslToRgb(ColorHsl input)
{
float r;
float g;
float b;
float c;
float x;
float m;
System.Diagnostics.Debug.Assert(input.h >= 0.0f);
c = 1.0f - System.Math.Abs(2.0f*input.l - 1.0f) * input.s;
x = c *(1.0f - (float)System.Math.Abs((float)((input.h / 0.25f) % 2.0f) - 1.0));
m = input.l - c*0.5f;
if( input.h < 60.0f/360.0f )
{
r = c;
g = x;
b = 0.0f;
}
else if( input.h < 120.0f/360.0f )
{
r = x;
g = c;
b = 0.0f;
}
else if( input.h < 180.0f/360.0f )
{
r = 0.0f;
g = c;
b = x;
}
else if( input.h < 240.0f/360.0f )
{
r = 0.0f;
g = x;
b = c;
}
else if( input.h < 300.0f/360.0f )
{
r = x;
g = 0.0f;
b = c;
}
else
{
r = c;
g = 0.0f;
b = x;
}
r += m;
g += m;
b += m;
return new ColorRgb(r, g, b);
}
public static ColorHsl rgbToHsl(ColorRgb rgb)
{
ColorHsl result;
float min;
EnumRgb rgbMin;
float max;
EnumRgb rgbMax;
result = new ColorHsl();
rgbMax = EnumRgb.R;
max = rgb.r;
if (rgb.g > max)
{
rgbMax = EnumRgb.G;
max = rgb.g;
}
if (rgb.b > max)
{
rgbMax = EnumRgb.B;
max = rgb.b;
}
rgbMin = EnumRgb.R;
min = rgb.r;
if (rgb.g < min)
{
rgbMin = EnumRgb.G;
min = rgb.g;
}
if (rgb.b < min)
{
rgbMin = EnumRgb.B;
min = rgb.b;
}
result.h = result.s = result.l = (max + min) * 0.5f;
if (rgbMax == rgbMin)
{
// accromatic
result.h = result.s = 0.0f;
}
else
{
float d;
d = max - min;
result.s = (result.l > 0.5f) ? d / (2.0f - max - min) : d / (max + min);
if (rgbMax == EnumRgb.R)
{
result.h = (rgb.g - rgb.b) / d + ((rgb.g < rgb.b) ? 6.0f : 0.0f);
}
else if (rgbMax == EnumRgb.G)
{
result.h = (rgb.b - rgb.r) / d + 2.0f;
}
else
{
result.h = (rgb.r - rgb.g) / d + 4.0f;
}
result.h /= 6.0f;
}
return result;
}
