On 8 January 2011 16:27, C K Kashyap
Hi, I've written a function to encode a color value of type (Int,Int,Int) into 8,16 or 32 byte ByteString depending on the value of bits per pixel. This is for my VNC server implementation. I'd appreciate some feedback on the Haskellism of the implementation.
import Data.Bits import Data.ByteString.Lazy import Data.Binary.Put import Data.Word
type Red = Int type Green = Int type Blue = Int type Color = (Red,Green,Blue)
encode :: Color -> Int-> Int-> Int-> Int-> Int-> Int-> Int -> ByteString encode (r,g,b) bitsPerPixel redMax greenMax blueMax redShift greenShift blueShift = runPut $ do case bitsPerPixel of 8 -> putWord8 z8 16 -> putWord16be z16 32 -> putWord32be z32 where z8 = (fromIntegral $ nr + ng + nb) :: Word8 z16 = (fromIntegral $ nr + ng + nb) :: Word16 z32 = (fromIntegral $ nr + ng + nb) :: Word32 nr = scale r redMax redShift ng = scale g greenMax greenShift nb = scale b blueMax blueShift scale c cm cs = (c * cm `div` 255) `shift` cs
The more "Haskellian" approach would be to use a dedicated datatype to specify the number of bits, not to have a partial function on Int. Possibly even encode the RGB triple such that it specifies the number of bits rather than separating each value. -- Ivan Lazar Miljenovic Ivan.Miljenovic@gmail.com IvanMiljenovic.wordpress.com