// credit to foley/van dam gfx book
public static HSBColor ColorToHsb(Color c)
{
float minval,maxval,delta;
float r=c.R/255.0f,g=c.G/255.0f,b=c.B/255.0f;
HSBColor hsbc = new HSBColor();
maxval = Math.Max( r, Math.Max(g,b) );
minval = Math.Min( r, Math.Min(g,b) );
hsbc.B = (maxval + minval) / 2.0f;
if(maxval==minval)
{
// grayscale
hsbc.S = 0.0f;
hsbc.H = 0.0f;
return hsbc;
}
if(hsbc.B < 0.5f)
hsbc.S = (maxval - minval) / (maxval + minval);
else
hsbc.S = (maxval - minval) / (2.0f - maxval - minval);
delta = maxval-minval;
if(r==maxval)
hsbc.H = (g-b) / delta;
else if (g==maxval)
hsbc.H = 2.0f + (b-r) / delta;
else if (b==maxval)
hsbc.H = 4.0f + (r-g) / delta;
hsbc.H = hsbc.H * 60.0f;
while(hsbc.H<0.0f) hsbc.H += 360.0f;
while(hsbc.H>360.0f) hsbc.H -= 360.0f;
return hsbc;
}
