Library for PPM images
m (I'll get it right in a minute...)
Revision as of 11:46, 16 April 2007
Here's a trivial little thing I wrote for saving PPM images.
For those that don't know, PPM is probably the simplest possible image file format that other software will actually read! For example, IrfanView will read it. Thus, this is a simple, light-weight way to write programs that will output graphics files, using only pure Haskell 98 I/O.
module PPM (make_ppm, save_ppm) where import Colour save_ppm :: FilePath -> [[Colour]] -> IO () save_ppm f css = writeFile f $ make_ppm css make_ppm :: [[Colour]] -> String make_ppm css = "P3\n" ++ (show $ length $ head css) ++ " " ++ (show $ length css) ++ " 255\n" ++ (unlines $ map unwords $ group 15 $ map show $ concatMap colour $ concat css) group _  =  group n xs = let (xs0,xs1) = splitAt n xs in xs0 : group n xs1 colour (Colour r g b) = [channel r, channel g, channel b] channel :: Double -> Int channel = floor . (255*) . min 1 . max 0
The code is actually designed to work with my Library for colours - but you can supply something of your own if you prefer.