basic ff reading/writing
Getty Ritter
5 years ago
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dist
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dist-*
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*~
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cabal-dev
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*.o
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*.hi
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*.chi
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*.chs.h
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*.dyn_o
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*.dyn_hi
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.hpc
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.hsenv
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.cabal-sandbox/
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cabal.sandbox.config
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*.prof
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*.aux
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*.hp
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*.eventlog
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cabal.project.local
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.ghc.environment.*
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name: farbfeld
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version: 0.1.0.0
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-- synopsis:
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-- description:
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license: BSD3
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author: Getty Ritter <gettylefou@gmail.com>
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maintainer: Getty Ritter <gettylefou@gmail.com>
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copyright: @2018 Getty Ritter
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-- category:
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build-type: Simple
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cabal-version: >=1.14
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library
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hs-source-dirs: src
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ghc-options: -Wall
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build-depends: base >=4.7 && <5
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, bytestring
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, cereal
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, array
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default-language: Haskell2010
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default-extensions: ScopedTypeVariables
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exposed-modules: Image.Farbfeld
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{-# LANGUAGE OverloadedStrings #-}
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{-# LANGUAGE RecordWildCards #-}
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module Image.Farbfeld
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( Image(..)
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, Pixel(..)
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, parseImage
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, emitImage
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) where
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import Control.Monad (when, forM_)
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import Data.Array (Array, array, bounds, (!))
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import Data.ByteString.Lazy (ByteString)
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import Data.Word (Word16, Word32)
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import qualified Data.Serialize as S
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newtype Image = Image
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{ imgPixels :: Array (Word32, Word32) Pixel
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} deriving (Eq, Show)
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data Pixel = Pixel
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{ pxRed :: !Word16
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, pxGreen :: !Word16
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, pxBlue :: !Word16
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, pxAlpha :: !Word16
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} deriving (Eq, Show)
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parseImage :: ByteString -> Either String Image
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parseImage = S.runGetLazy $ do
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magic <- S.getByteString 8
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when (magic /= "farbfeld") $
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fail "Unable to find farbfeld magic number"
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w <- S.getWord32be
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h <- S.getWord32be
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imgPixels <- array ((0, 0), (w-1, h-1)) <$> sequence
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[ sequence ((x, y), getPixel)
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| y <- [0..h-1]
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, x <- [0..w-1]
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]
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return Image { .. }
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emitImage :: Image -> ByteString
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emitImage (Image pixels) = S.runPutLazy $ do
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S.putByteString "farbfeld"
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let (w, h) = snd (bounds pixels)
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S.putWord32be (w + 1)
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S.putWord32be (h + 1)
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forM_ [0..h] $ \y ->
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forM_ [0..w] $ \x -> do
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let Pixel { .. } = pixels ! (x, y)
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S.putWord16be pxRed
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S.putWord16be pxGreen
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S.putWord16be pxBlue
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S.putWord16be pxAlpha
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getPixel :: S.Get Pixel
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getPixel = Pixel
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<$> S.getWord16be
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<*> S.getWord16be
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<*> S.getWord16be
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<*> S.getWord16be
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