module BlueCircle
where

import Pan

{-# INLINE circle       #-}
{-# INLINE circleReg    #-}


circle :: Frac -> ImageC
circle r = condR (circleReg r) blueI whiteI

-- circleReg :: Frac -> Image Bool
-- circleReg r (Pt x y) = distO (Pt x y) < r

circleReg :: Frac -> Region
circleReg r (Pt x y) = x*x + y*y < r*r


effect :: UI DisplayFun
effect = do
  v <- makeSlider "Radius" (10,100) 30
  imageToDisplayFun (circle v)