-- Hoogle documentation, generated by Haddock
-- See Hoogle, http://www.haskell.org/hoogle/


-- | Distance transform function.
--   
--   An n-D distance transform that computes the Euclidean distance between
--   each element in a discrete field and the nearest cell containing a
--   zero.
--   
--   The algorithm implemented is based off of Meijster et al., <i>"A
--   general algorithm for computing distance</i> <i>transforms in linear
--   time."</i> Parallel versions of both the Euclidean distance transform
--   and squared Euclidean distance transform are also provided.
@package DistanceTransform
@version 0.1.2


-- | Helpers for performing nested loop iteration. Includes variants for
--   parallel computation.
module DistanceTransform.Internal.Indexer

-- | We use a zipper on list to walk over dimensions of an array.
data Zipper a
Zip :: [a] -> a -> [a] -> Zipper a

-- | Create a <a>Zipper</a> from a non-empty list, with the cursor on the
--   leftmost element.
toZipper :: a -> [a] -> Zipper a

-- | Create a <a>Zipper</a> from a non-empty list, with the cursor on the
--   leftmost element. An exception is thrown if the given list is empty.
unsafeToZipper :: [a] -> Zipper a

-- | Convert a <a>Zipper</a> to a list.
fromZipper :: Zipper a -> [a]

-- | Move a <a>Zipper</a> to the left.
left :: Zipper a -> Maybe (Zipper a)
unsafeLeft :: Zipper a -> Zipper a
right :: Zipper a -> Maybe (Zipper a)

-- | Comonadic coreturn: produce the value a <a>Zipper</a> is currently
--   focused upon.
focus :: Zipper a -> a

-- | Slide a <a>Zipper</a> over until focused on its rightmost element.
rightmost :: Zipper a -> Zipper a

-- | Since we are using <a>Zipper</a>s to track the size of
--   multidemensional arrays, the sum of all zipper elements gives the size
--   of the entire array.
zipSum :: Num a => Zipper a -> a

-- | Computes the step between consective elements at the currently focused
--   dimension. This involves stepping over all nested dimensions.
zipStep :: Num a => Zipper a -> a

-- | Computes the stride between rows at the currently focused dimension.
--   This involves stepping over the rest of the current row along all
--   nested dimensions.
zipStride :: Num a => Zipper a -> a
zipFoldM :: Monad m => Zipper Int -> (a -> Int -> m a) -> a -> [Int] -> m ()
parChunkMapM_ :: (a -> IO ()) -> [a] -> IO ()
parZipFoldM :: Zipper Int -> (a -> Int -> IO a) -> a -> [Int] -> IO ()
zipMapM_ :: Monad m => Zipper Int -> (Int -> m ()) -> [Int] -> m ()
zipFoldMAsYouDo :: Monad m => Zipper Int -> (Int -> Int -> m ()) -> m ()
parZipFoldMAsYouDo :: Zipper Int -> (Int -> Int -> IO ()) -> IO ()


-- | N-dimensional parallel Euclidean distance transform using an approach
--   derived from: Meijster et al., <i>"A general algorithm for</i>
--   <i>computing distance transforms in linear time."</i>
module DistanceTransform.Euclidean

-- | Compute the Euclidean distance transform of an N-dimensional array.
--   Dimensions given as <tt>[width,height,depth...]</tt>. The left-most
--   dimension is the inner-most. For an array representing a 2D collection
--   in row-major format, we would give <tt>[width,height]</tt> or
--   <tt>[columns,rows]</tt>.
edt :: (Integral a, Floating b, Vector v a, Vector v b, Vector v Int) => [Int] -> v a -> v b

-- | Compute the Euclidean distance transform of an N-dimensional array
--   using multiple processor cores. Dimensions given as
--   <tt>[width,height,depth...]</tt>. The left-most dimension is the
--   inner-most. For an array representing a 2D collection in row-major
--   format, we would give <tt>[width,height]</tt> or
--   <tt>[columns,rows]</tt>.
edtPar :: (Integral a, Floating b, Vector v a, Vector v b, Vector v Int) => [Int] -> v a -> v b

-- | Compute the squared Euclidean distance transform of an N-dimensional
--   array. Dimensions given as <tt>[width,height,depth...]</tt>. The
--   left-most dimension is the inner-most.
sedt :: (Vector v a, Vector v Int, Integral a) => [Int] -> v a -> v Int

-- | Compute the squared Euclidean distance transform of an N-dimensional
--   array using multiple processor cores. Dimensions given as
--   <tt>[width,height,depth...]</tt>. The left-most dimension is the
--   inner-most.
sedtPar :: (Vector v a, Vector v Int, Integral a) => [Int] -> v a -> v Int