public static Color HSL2RGB( HSL hsl )
{
// by Donald (Sterex 1996), [email protected], 20011124
int lMax = (int)(hsl.L * 255.0);
if ( hsl.S > 0 ) {
int lMin = (int)((100 - hsl.S * 100.0) * (double)lMax / 100.0);
double q = (lMax - lMin) / 60;
int r, g, b, lMid;
int h = (int)(hsl.H * 360);
if ( h < 60 ) {
lMid = (int)((h - 0) * q + lMin);
r = lMax; g = lMid; b = lMin;
}
else if ( h < 120 ) {
lMid = (int)((-(h - 120)) * q + lMin);
r = lMid; g = lMax; b = lMin;
}
else if ( h < 180 ) {
lMid = (int)((h - 120) * q + lMin);
r = lMin; g = lMax; b = lMid;
}
else if ( h < 240 ) {
lMid = (int)((-(h - 240)) * q + lMin);
r = lMin; g = lMid; b = lMax;
}
else if ( h < 300 ) {
lMid = (int)((h - 240) * q + lMin);
r = lMid; g = lMin; b = lMax;
}
else {
lMid = (int)((-(h - 360)) * q + lMin);
r = lMax; g = lMin; b = lMid;
}
return Color.FromArgb( r, g, b );
}
else {
return Color.FromArgb( lMax, lMax, lMax );
}
}
public static HSL RGB2HSLX( Color c )
{
if ( init == 0 ) {
for ( init = 2; init < 256; ++init ) {
Lum[init] = ((double)init)/255;
}
for ( init = 1; init < 256; ++init ) {
QTab[init] = 60/init;
}
}
int lMax, lMin;
if ( c.R > c.G ) {
lMax = c.R; lMin = c.G;
}
else {
lMax = c.G; lMin = c.R;
}
if ( c.B > lMax )
lMax = c.B;
else if ( c.B < lMin ) {
lMin = c.B;
}
HSL hsl = new HSL();
hsl.L = Lum[lMax];
int lDifference = lMax - lMin;
if ( lDifference > 0 ) {
// do a 65K 2D lookup table here for more speed if needed
hsl.S = ((double)lDifference) / lMax;
if ( lMax == c.R ) {
if ( c.B > c.G )
hsl.H = ((QTab[lDifference] * (c.G - c.B)) / 360) + 1;
else
hsl.H = ((QTab[lDifference] * (c.G - c.B)) / 360);
}
else if ( lMax == c.G ) {
hsl.H = (QTab[lDifference] * (c.B - c.R) + 120) / 360;
}
else {
hsl.H = (QTab[lDifference] * (c.R - c.G) + 240) / 360;
}
}
else {
hsl.S = 0;
hsl.H = 0;
}
return hsl;
}
/// <summary>
/// Converts a colour from HSL to RGB
/// </summary>
/// <remarks>Adapted from the algoritm in Foley and Van-Dam</remarks>
/// <param name="hsl">The HSL value</param>
/// <returns>A Color structure containing the equivalent RGB values</returns>
public static Color HSL2RGBx( HSL hsl )
{
double r=0,g=0,b=0;
double temp1,temp2;
if(hsl.L==0) {
r=g=b=0;
}
else {
if(hsl.S==0) {
r=g=b=hsl.L;
}
else {
temp2 = ((hsl.L<=0.5) ? hsl.L*(1.0+hsl.S) : hsl.L+hsl.S-(hsl.L*hsl.S));
temp1 = 2.0*hsl.L-temp2;
double[] t3=new double[]{hsl.H+1.0/3.0,hsl.H,hsl.H-1.0/3.0};
double[] clr=new double[]{0,0,0};
for(int i=0;i<3;i++) {
if(t3[i]<0)
t3[i]+=1.0;
if(t3[i]>1)
t3[i]-=1.0;
if(6.0*t3[i] < 1.0)
clr[i]=temp1+(temp2-temp1)*t3[i]*6.0;
else if(2.0*t3[i] < 1.0)
clr[i]=temp2;
else if(3.0*t3[i] < 2.0)
clr[i]=(temp1+(temp2-temp1)*((2.0/3.0)-t3[i])*6.0);
else
clr[i]=temp1;
}
r=clr[0];
g=clr[1];
b=clr[2];
}
}
return Color.FromArgb((int)(255*r),(int)(255*g),(int)(255*b));
}