Rectangle.hs

-- | Rectangles from this module are used to specify areas for operations.
module GEGL.Rectangle
  ( FFI.GeglRectangle(..)
  , gegl_rectangle_intersect
  -- , gegl_rectangle_infinite_plane
  ) where

import Foreign.Marshal.Utils (new)
import Foreign.Marshal.Alloc (free)
import Foreign.Storable (peek)

import qualified GEGL.FFI.Rectangle as FFI

-- | Calculates the intersection of two rectangles.
gegl_rectangle_intersect
  :: FFI.GeglRectangle            -- ^ A rectangle
  -> FFI.GeglRectangle            -- ^ A rectangle
  -> IO (Maybe FFI.GeglRectangle) -- ^ Returns a 'FFI.GeglRectangle' if
                                  --   rectangles intersect, otherwise 'Nothing'
gegl_rectangle_intersect a b = do
  pa <- new a
  pb <- new b
  res <- FFI.c_gegl_rectangle_intersect pa pa pb
  ret <- if res
    then do
      iret <- peek pa
      return $ Just iret
    else
      return Nothing
  free pa
  free pb
  return ret

-- -- | returns a 'GeglRectangle' representing an inifinite plane
-- gegl_rectangle_infinite_plane
--   :: IO FFI.GeglRectangle -- ^ The infinite plane
-- gegl_rectangle_infinite_plane = do
--   rectPtr <- FFI.c_gegl_rectangle_infinite_plane
--   rect <- peek rectPtr
--   free rectPtr