module Balls where

import GraphicsUtils 


drawBalls :: Window-> Color-> Point-> Point-> IO ()
drawBalls w c (x1, y1) (x2, y2) =    
  if x1 >= x2 then return ()
  else let el = ellipse (x1, y1) (x2, y2)
       in do drawInWindow w (withColor c el)
             drawBalls w (nextColor c) 
                         (x1+deltaX, y1) 
                         (x2-deltaX, y2)    
deltaX :: Int
deltaX = 25

nextColor :: Color-> Color    
nextColor Red   = Green
nextColor Green = Blue
nextColor Blue  = Red    

main :: IO ()
main = runGraphics $ do
   w <- openWindow "Balls!" (500,500)
   drawBalls w Blue (25, 25) (485, 485)
   getKey w
   closeWindow w