ReadImageFile.hs

-- ReadImageFile.hs

import qualified Codec.Picture as Picture
import qualified Data.Vector.Storable as Vector

intToDouble i = fromIntegral i::Double

printImageInfo imageType image =
 putStrLn ("Length: " ++ (show imgLength)) >>
 putStrLn ("Numbers per pixel: " ++ (show numbersPerPixel)) >>
 putStrLn ("Minimum value: " ++ (show $ Vector.minimum imgData)) >>
 putStrLn ("Maximum value: " ++ (show $ Vector.maximum imgData)) >>
 putStrLn ("Image type: " ++ imageType) >>
 putStrLn ("Dimensions: (" ++ (show width) ++ "," ++ (show height) ++ ")")
 where
  imgData = Picture.imageData image
  imgLength = Vector.length imgData
  width = Picture.imageWidth image
  height = Picture.imageHeight image
  numbersPerPixel = (intToDouble imgLength) / (intToDouble width) / (intToDouble height)

processImage img =
 case img of
  Picture.ImageY8 i -> printImageInfo "ImageY8" i
  Picture.ImageYF i -> printImageInfo "ImageYF" i
  Picture.ImageYA8 i -> printImageInfo "ImageYA8" i
  Picture.ImageRGB8 i -> printImageInfo "ImageRGB8" i
  Picture.ImageRGBF i -> printImageInfo "ImageRGBF" i
  Picture.ImageRGBA8 i -> printImageInfo "ImageRGBA8" i
  Picture.ImageYCbCr8 i -> printImageInfo "ImageYCbCr8" i

readImageFile imageFile =
 putStrLn ("\nReading image: " ++ imageFile) >>
 Picture.readImage imageFile >>= \result ->
 case result of
  Left error -> putStrLn ("ERROR: " ++ show error)
  Right image -> processImage image

main =
 readImageFile "Halflife-Haskell.jpg" >>
 readImageFile "development-haskell.png"

-- Download images from:
-- http://images.wikia.com/uncyclopedia/images/f/fb/Halflife-Haskell.jpg
-- http://www.iconattitude.com/icons/open_icon_library/apps/png/256/development-haskell.png