How openFrameworks handles

gistfile1.txt

template<typename PixelType>
void ofColor_<PixelType>::getHsb(float& hue, float& saturation, float& brightness) const {
    float max = getBrightness();
	
	float min = r;
	if(g < min) {
		min = g;
	}
	if(b < min) {
		min = b;
	}
	
	if(max == min) { // grays
		hue = 0.f;
		saturation = 0.f;
		brightness = max;
		return;
	}
	
	float hueSixth;
	if(r == max) {
		hueSixth = (g - b) / (max - min);
		if(hueSixth < 0.f)
			hueSixth += 6.f;
	} else if (g == max) {
		hueSixth = 2.f + (b - r) / (max - min);
	} else {
		hueSixth = 4.f + (r - g) / (max - min);
	}
	hue = limit() * hueSixth / 6.f;
	saturation = limit() * (max - min) / max;
	brightness = max;
}

Referenced

template<>
float ofColor_<float>::limit() {
    return 1.f;
}