RGB和HSV颜色空间的快速近似转换算法

RGB转化到HSV的算法:
max = max(R, G, B)
min = min(R, G, B)
if R = max, H = (G - B)/(max - min)
if G = max, H = 2 + (B - R)/(max - min)
if B = max, H = 4 + (R - G)/(max - min)

H = H * 60
if H < 0, H = H + 360

V = max(R, G, B)
S = (max - min)/max

HSV转化到RGB的算法
if s = 0
R = G = B = V
else
H /= 60
i = INTEGER(H)

f = H - i
a = V * ( 1 - s )
b = V * ( 1 - s * f )
c = V * ( 1 - s * (1 - f ) )

switch(i)
case 0: R = V; G = c; B = a;
case 1: R = b; G = v; B = a;
case 2: R = a; G = v; B = c;
case 3: R = a; G = b; B = v;
case 4: R = c; G = a; B = v;
case 5: R = v; G = a; B = b;