amaranth/src/Canvas.hs

module Canvas where

import Graphics.Gloss.Data.Picture ( Picture (Text), pictures, scale )
import Graphics.Gloss.Interface.IO.Interact ( Event (EventKey), KeyState (Down), Key (Char) )

data Canvas = Canvas {
    items   ::  [Picture],
    mode    ::  Mode   
}

data Mode = Brush | Eraser deriving (Eq, Show)

showMode :: Canvas -> Picture
showMode canv = scale 0.1 0.1 $ Text ( show (mode canv))

render :: Canvas -> Picture
render canv = pictures ( showMode canv : items canv ) 

handle :: Event -> Canvas -> Canvas
handle (EventKey (Char 'b') Down _ _ ) canv = canv { mode = Brush }
handle (EventKey (Char 'e') Down _ _ ) canv = canv { mode = Eraser }
handle _ canv = canv

update :: Float -> Canvas -> Canvas
update _ canv = canv