Aspect combinator

Maintaining a proportional relationship between the width and height of a component:

aspect :: Int -> Int -> DisplayHandle -> DisplayHandle
aspect px py dh

main =
 mkDC ["*name: Aspect"]       >>= \ dc ->
  button (text "Buttons are forever") () dc >>= \ (_,dh) ->
 realiseDH dc (aspect 3 4 dh) >>
 return ()