mediaLib Library Functions          mlibImageColorRGB2HSL(3MLIB)



NAME
     mlibImageColorRGB2HSL - RGB to HSL color conversion

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

     mlibstatus mlibImageColorRGB2HSL(mlibimage *dst, const mlibimage *src);


DESCRIPTION
     The mlibImageColorRGB2HSL() 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 MLIBYTE 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          mlibImageColorRGB2HSL(3MLIB)



     for MLIBSHORT 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 MLIBUSHORT images, the following applies:

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



     and for MLIBINT 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 MLIBSUCES if  successful.  Otherwise
     it returns MLIBFAILURE.

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







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mediaLib Library Functions          mlibImageColorRGB2HSL(3MLIB)



     
           ATRIBUTE TYPE               ATRIBUTE VALUE       
    
     Interface Stability          Committed                   
    
     MT-Level                     MT-Safe                     
    


SEE ALSO
     mlibImageColorHSL2RGB(3MLIB),
     mlibImageColorHSL2RGBFp(3MLIB),
     mlibImageColorRGB2HSLFp(3MLIB), attributes(5)










































SunOS 5.11           Last change: 2 Mar 2007                    3