Example usage of outline' on a ColorImage

OutlineExample.hs

import Data.Image
import Data.Image.Interactive
import System.IO.Unsafe

stopImage = unsafePerformIO $ do
  stop <- readColorImage "images/stop.ppm"
  return stop
  
binaryStop = (r + g + b) .> 196 where
  (r, g, b) = colorImageToRGB stopImage

grayToColor img = makeImage (rows img) (cols img) toColor where
  toColor r c = RGB (g, g, g) where
    g = ref img r c

outlineBlue :: ColorImage
outlineBlue = outline' white blue (grayToColor binaryStop) where
  white = RGB (1,1,1)
  blue = RGB (0,0,1)