Manual Pages for UNIX Operating System command usage for man mlib_ImageColorRGB2HSL

mediaLib Library Functions          mlib_ImageColorRGB2HSL(3MLIB)



NAME
     mlib_ImageColorRGB2HSL - RGB to HSL color conversion

SYNOPSIS
     cc [ flag... ] file... -lmlib [ library... ]
     #include 

     mlib_status mlib_ImageColorRGB2HSL(mlib_image *dst, const mlib_image *src);


DESCRIPTION
     The mlib_ImageColorRGB2HSL() function performs a  conversion
     from  red/green/blue to hue/saturation/lightness. 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)

          L = (V + Vmin)/2

          S = (V - Vmin)/(V + Vmin)         if L < 1/2
          S = (V - Vmin)/(2 - V - Vmin)     if L > 1/2

          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, L, 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, l),
     then for MLIB_BYTE images, the following applies:

          R = r/255
          G = g/255
          B = b/255
          h = H*256
          s = S*255
          l = L*255






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mediaLib Library Functions          mlib_ImageColorRGB2HSL(3MLIB)



     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
          l = L*65535 - 32768



     for MLIB_USHORT images, the following applies:

          R = r/65535
          G = g/65535
          B = b/65535
          h = H*65536
          s = S*65535
          l = L*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
          l = L*4294967295 - 2147483648


PARAMETERS
     The function takes the following arguments:

     dst    Pointer to destination image.


     src    Pointer to source image.


RETURN VALUES
     The function returns MLIB_SUCCESS if  successful.  Otherwise
     it returns MLIB_FAILURE.

ATTRIBUTES
     See attributes(5) for descriptions of the  following  attri-
     butes:







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mediaLib Library Functions          mlib_ImageColorRGB2HSL(3MLIB)



     ____________________________________________________________
    |       ATTRIBUTE TYPE        |       ATTRIBUTE VALUE       |
    |_____________________________|_____________________________|
    | Interface Stability         | Committed                   |
    |_____________________________|_____________________________|
    | MT-Level                    | MT-Safe                     |
    |_____________________________|_____________________________|


SEE ALSO
     mlib_ImageColorHSL2RGB(3MLIB),
     mlib_ImageColorHSL2RGB_Fp(3MLIB),
     mlib_ImageColorRGB2HSL_Fp(3MLIB), attributes(5)










































SunOS 5.11           Last change: 2 Mar 2007                    3