RGB HSV HLS三种色彩模式转换（C语言实现）

Android项目上处理图像的代码（注释全部去掉）

void RGB2HSV( uint16_t * h, uint16_t * s, uint16_t * v, uint8_t r, uint8_t g, uint8_t b)
{
	double rr, gg, bb;
	double hh, ss, vv;
	double cmax, cmin, cdes;

	rr = r;
	gg = g;
	bb = b;

	cmax = (rr > gg) ? rr : gg;
	if (bb > cmax) {
	    cmax = bb;
	}

	cmin = (rr < gg) ? rr : gg;
	if (bb < cmin) {
	    cmin = bb;
	}

	cdes = cmax - cmin;
	vv = cmax;
	if (cdes != 0) {
	    ss = cdes * SCALE / cmax;
	    if (cmax == rr) {
	        hh = (gg - bb) * SCALE / cdes;
	    }else if (cmax == gg) {
	        hh = (bb - rr) * SCALE / cdes + 2 * H_SCALE;
	    }else {
	        hh = (rr - gg) * SCALE / cdes + 4 * H_SCALE;
	    }
	}else if (cmax != 0) {
	    ss = cdes * SCALE / cmax;
	    hh = 0;
	}else {
	    ss = 0;
	    hh = 0;
	}
	if (hh < 0) {
	    hh += 6 * H_SCALE;
	}

	*h = hh * H_GETA;
	*s = ss * H_GETA;
	*v = vv * H_GETA;
}

void HSV2RGB( uint8_t *r, uint8_t *g, uint8_t *b, uint16_t h, uint16_t s, uint16_t v)
{
	double rr = 0, gg = 0, bb = 0;
	double hh, ss, vv;

	if (h == 6 * H_GETA * H_SCALE) {
	    h = 0;
	}
	hh = (double)h / H_GETA;
	ss = (double)s / GETA;
	vv = (double)v / GETA;

	switch((int)(hh / H_SCALE)) {
	    case 0:
	        rr = SCALE;
	        gg = hh;
	        bb = 0;
	        break;
	    case 1:
	        rr = 2 * H_SCALE - hh;
	        gg = SCALE;
	        bb = 0;
	        break;
	    case 2:
	        rr = 0;
	        gg = SCALE;
	        bb = hh - 2 * H_SCALE;
	        break;
	    case 3:
	        rr = 0;
	        gg = 4 * H_SCALE - hh;
	        bb = SCALE;
	        break;
	    case 4:
	        rr = hh - 4 * H_SCALE;
	        gg = 0;
	        bb = SCALE;
	        break;
	    case 5:
	        rr = SCALE;
	        gg = 0;
	        bb = 6 * H_SCALE - hh;
	        break;
	}

	rr = (rr + (SCALE - rr) * (SCALE - ss) / SCALE) * vv / SCALE;
	gg = (gg + (SCALE - gg) * (SCALE - ss) / SCALE) * vv / SCALE;
	bb = (bb + (SCALE - bb) * (SCALE - ss) / SCALE) * vv / SCALE;

	*r = rr;
	*g = gg;
	*b = bb;
	if (*r > 255)*r = 255;
	if (*g > 255)*g = 255;
	if (*b > 255)*b = 255;
}

void RGB2HLS( double *h, double *l, double *s, uint8_t r, uint8_t g, uint8_t b)
{
	double dr = (double)r/255;
	double dg = (double)g/255;
	double db = (double)b/255;
	double cmax = MAX(dr, MAX(dg, db));
	double cmin = MIN(dr, MIN(dg, db));
	double cdes = cmax - cmin;
	double hh, ll, ss;

	ll = (cmax+cmin)/2;
	if(cdes){
	    if(ll <= 0.5)
	        ss = (cmax-cmin)/(cmax+cmin);
	    else
	        ss = (cmax-cmin)/(2-cmax-cmin);

	    if(cmax == dr)
	        hh = (0+(dg-db)/cdes)*60;
	    else if(cmax == dg)
	        hh = (2+(db-dr)/cdes)*60;
	    else// if(cmax == b)
	        hh = (4+(dr-dg)/cdes)*60;
	    if(hh<0)
	        hh+=360;
	}else
	    hh = ss = 0;

	*h = hh;
	*l = ll;
	*s = ss;
}

void HLS2RGB( uint8_t *r, uint8_t *g, uint8_t *b, double h, double l, double s)
{
	double cmax,cmin;

	if(l <= 0.5)
		cmax = l*(1+s);
	else
	    cmax = l*(1-s)+s;
	cmin = 2*l-cmax;

	if(s == 0){
	    *r = *g = *b = l*255;
	}else{
	    *r = HLS2RGBvalue(cmin,cmax,h+120)*255;
	    *g = HLS2RGBvalue(cmin,cmax,h)*255;
	    *b = HLS2RGBvalue(cmin,cmax,h-120)*255;
	}
}

double HLS2RGBvalue(double n1,double n2, double hue)
{
	if(hue > 360)
	    hue -= 360;
	else if(hue < 0)
	    hue += 360;
	if(hue < 60)
	    return n1+(n2-n1)*hue/60;
	else if(hue < 180)
	    return n2;
	else if(hue < 240)
	    return n1+(n2-n1)*(240-hue)/60;
	else
	    return n1;
}