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|
{-|
Module : PFM
Description : Debevec PFM reader
Copyright : (c) 2019, Yann Herklotz Grave
License : GPL-3
Maintainer : ymherklotz [at] gmail [dot] com
Stability : experimental
Portability : POSIX
Debevec PFM reader
-}
module PFM where
import Control.Applicative ((<|>))
import Control.Monad (void)
import Data.Attoparsec.ByteString (Parser)
import qualified Data.Attoparsec.ByteString as P
import Data.Binary.Get (runGet)
import Data.Binary.IEEE754 (getFloat32be, getFloat32le)
import Data.ByteString (ByteString)
import qualified Data.ByteString as B
import Data.ByteString.Lazy (fromStrict)
import Data.Text (Text)
import qualified Data.Text as T
import qualified Data.Text.Encoding as T
import Data.Word (Word8)
data Image = Image { width :: Int
, height :: Int
, colour :: [Colour]
} deriving (Show)
data Colour = Colour { r :: Float
, g :: Float
, b :: Float
}
| Mono Float
deriving (Show)
matchText :: Text -> Parser ByteString
matchText = P.string . T.encodeUtf8
magicNumMono :: Parser ()
magicNumMono = void $ matchText "Pf"
magicNumRGB :: Parser ()
magicNumRGB = void $ matchText "PF"
skipNewline :: Parser ()
skipNewline = P.skip isNewline
where
isNewline w = w == 13 || w == 10
skipSpace :: Parser ()
skipSpace = P.skip (== 32)
decode :: (Read a) => [Word8] -> a
decode = read . T.unpack . T.decodeUtf8 . B.pack
matchMult :: String -> Parser [Word8]
matchMult = P.many1 . P.satisfy . P.inClass
num :: Parser Int
num = decode <$> matchMult "0-9"
endianness :: Parser Float
endianness = decode <$> matchMult "0-9.-"
float :: Parser Float
float = runGet getFloat32le . fromStrict <$> P.take 4
header :: Parser (Int, Int, Float)
header = do
magicNumRGB
skipNewline
n1 <- num
skipSpace
n2 <- num
skipNewline
s <- endianness
skipNewline
return (n1, n2, s)
parseColour :: Parser Colour
parseColour = do
ri <- float
gi <- float
bi <- float
return $ Colour ri gi bi
parseMono :: Parser Colour
parseMono = Mono <$> float
parser :: Parser Image
parser = do
(w, h, f) <- header
c <- P.many1 parseColour
return $ Image w h c
parse :: ByteString -> IO ()
parse s = case P.parseOnly parser s of
Left str -> putStrLn str
Right i -> print i
|
