cc [ flag... ] file... –lmlib [ library... ] #include <mlib.h> mlib_status mlib_ImageColorRGB2HSV(mlib_image *dst, const mlib_image *src);
The mlib_ImageColorRGB2HSV() function performs a conversion from red/green/blue to hue/saturation/value. The source and destination images must be three-channel images.
It uses the following equations:
V = max(R, G, B) Vmin = min(R, G, B) S = (V - Vmin)/V H = (5.0 + (V - B)/(V - Vmin))/6 if R = V and G = Vmin H = (1.0 - (V - G)/(V - Vmin))/6 if R = V and B = Vmin H = (1.0 + (V - R)/(V - Vmin))/6 if G = V and B = Vmin H = (3.0 - (V - B)/(V - Vmin))/6 if G = V and R = Vmin H = (3.0 + (V - G)/(V - Vmin))/6 if B = V and R = Vmin H = (5.0 - (V - R)/(V - Vmin))/6 if B = V and G = Vmin H = 0.0 if R = G = B
where 0 ≤ R, G, B, V, Vmin, S ≤ 1 and 0 ≤ H < 1.
Assuming a pixel in the source image is (r, g, b) and its corresponding pixel in the destination image is (h, s, v), then for MLIB_BYTE images, the following applies:
R = r/255 G = g/255 B = b/255 h = H*256 s = S*255 v = V*255
for MLIB_SHORT images, the following applies:
R = (r + 32768)/65535 G = (g + 32768)/65535 B = (b + 32768)/65535 h = H*65536 - 32768 s = S*65535 - 32768 v = V*65535 - 32768
for MLIB_USHORT images, the following applies:
R = r/65535 G = g/65535 B = b/65535 h = H*65536 s = S*65535 v = V*65535
and for MLIB_INT images, the following applies:
R = (r + 2147483648)/4294967295 G = (g + 2147483648)/4294967295 B = (b + 2147483648)/4294967295 h = H*4294967296 - 2147483648 s = S*4294967295 - 2147483648 v = V*4294967295 - 2147483648
The function takes the following arguments:
Pointer to destination image.
Pointer to source image.
The function returns MLIB_SUCCESS if successful. Otherwise it returns MLIB_FAILURE.
See attributes(5) for descriptions of the following attributes:
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mlib_ImageColorHSV2RGB(3MLIB), mlib_ImageColorHSV2RGB_Fp(3MLIB), mlib_ImageColorRGB2HSV_Fp(3MLIB), attributes(5)