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


-- | Functional Combinators for Computer Vision
--   
--   Initial version; using HOpenCV as a backend
@package cv-combinators
@version 0.1


-- | Framework for expressing monadic actions that require initialization
--   and finalizers. This module provides a *functional* interface for
--   defining and chaining a series of processors.
--   
--   Motivating example: bindings to C libraries that use functions such
--   as: f(foo *src, foo *dst), where the pointer <tt>dst</tt> must be
--   pre-allocated. In this case we normally do:
--   
--   foo *dst = allocateFoo(); ... while (something) { f(src, dst); ... }
--   releaseFoo(dst);
--   
--   You can use the <a>runUntil</a> function below to emulate that loop.
--   
--   Processor is an instance of Category, Functor, Applicative and Arrow.
module AI.CV.Processor

-- | The type of Processors
--   
--   The semantic model is:
--   
--   <pre>
--   [[ Processor m o a b ]] = a -&gt; b
--   </pre>
--   
--   The idea is that the monad m is usually IO, and that a and b are
--   usually pointers. It is meant for functions that require a
--   pre-allocated output pointer to operate.
--   
--   <ul>
--   <li>a, b = the input and output types of the processor (think a -&gt;
--   b)</li>
--   <li>m = monad in which the processor operates</li>
--   <li>x = type of internal state</li>
--   </ul>
--   
--   The arguments to the constructor are:
--   
--   <ol>
--   <li>Processing function: Takes input and internal state, and returns
--   new internal state.</li>
--   <li>Allocator for internal state (this is run only once): Takes
--   (usually the first) input, and returns initial internal state.</li>
--   <li>Convertor from state x to output b: Takes internal state and
--   returns the output.</li>
--   <li>Releaser for internal state (finalizer, run once): Run after
--   processor is done being used, to release the internal state.</li>
--   </ol>
data Processor m a b
Processor :: (a -> x -> m x) -> (a -> m x) -> (x -> m b) -> (x -> m ()) -> Processor m a b
processor :: (Monad m) => (a -> x -> m x) -> (a -> m x) -> (x -> m b) -> (x -> m ()) -> Processor m a b

-- | Chains two processors serially, so one feeds the next.
chain :: (Monad m) => Processor m a b' -> Processor m b' b -> Processor m a b

-- | A processor that represents two sub-processors in parallel (although
--   the current implementation runs them sequentially, but that may change
--   in the future)
parallel :: (Monad m) => Processor m a b -> Processor m c d -> Processor m (a, c) (b, d)

-- | Constructs a processor that: given two processors, gives source as
--   input to both processors and runs them independently, and after both
--   have have finished, outputs their combined outputs.
--   
--   Semantic meaning, using Arrow's (&amp;&amp;&amp;) operator: [[
--   forkJoin ]] = &amp;&amp;&amp; Or, considering the Monad instance of
--   functions (which are the semantic meanings of a processor): [[
--   forkJoin ]] = liftM2 (,) Alternative implementation to consider: f
--   &amp;&amp;&amp; g = (,) <a>&amp;</a> f <a>*</a> g
forkJoin :: (Monad m) => Processor m a b -> Processor m a b' -> Processor m a (b, b')

-- | The identity processor: output = input. Semantically, [[ empty ]] = id
empty :: (Monad m) => Processor m a a

-- | Splits (duplicates) the output of a functor, or on this case a
--   processor.
split :: (Functor f) => f a -> f (a, a)

-- | 'f --&lt; g' means: split f and feed it into g. Useful for feeding
--   parallelized (***'d) processors. For example, a --&lt; (b
--   &amp;&amp;&amp; c)
(--<) :: (Functor (cat a), Category cat) => cat a a1 -> cat (a1, a1) c -> cat a c

-- | Runs the processor once: allocates, processes, converts to output, and
--   deallocates.
run :: (Monad m) => Processor m a b -> a -> m b

-- | Keeps running the processing function in a loop until a predicate on
--   the output is true. Useful for processors whose main function is after
--   the allocation and before deallocation.
runUntil :: (Monad m) => Processor m a b -> a -> (b -> m Bool) -> m b

-- | Runs the processor once, but passes the processing + conversion action
--   to the given function.
runWith :: (Monad m) => (m b -> m b') -> Processor m a b -> a -> m b'
instance (Monad m) => Arrow (Processor m)
instance (Monad m) => Applicative (Processor m a)
instance (Monad m) => Functor (Processor m a)
instance (Monad m) => Category (Processor m)


-- | ImageProcessors is a functional (Processor-based) interface to
--   computer vision using OpenCV.
--   
--   The Processor interface allows the primitives in this library to take
--   care of all the allocation / deallocation of resources and other
--   setup/teardown requirements, and to appropriately nest them when
--   combining primitives.
--   
--   Simple example:
--   
--   <pre>
--   win = window 0        -- The number is essentially a label for the window
--   cam = camera 0        -- Autodetect camera
--   edge = canny 30 190 3 -- Edge detecting processor using canny operator
--   
--   test = win . edge . cam   -- A processor that captures frames from camera and displays edge-detected version in the window.
--   </pre>
module AI.CV.ImageProcessors
type ImageSink = Processor IO (Ptr IplImage) ()
type ImageSource = Processor IO () (Ptr IplImage)
type ImageProcessor = Processor IO (Ptr IplImage) (Ptr IplImage)

-- | Some general utility functions for use with Processors and OpenCV
--   
--   Predicate for pressed keys
keyPressed :: (Show a) => a -> IO Bool

-- | Runs the processor until a predicate is true, for predicates, and
--   processors that take () as input (such as chains that start with a
--   camera).
runTill :: (Monad m) => Processor m () b -> (b -> m Bool) -> m b

-- | Name (and type) says it all.
runTillKeyPressed :: (Show a) => Processor IO () a -> IO ()

-- | A capture device, using OpenCV's HighGui lib's cvCreateCameraCapture
--   should work with most webcames. See OpenCV's docs for information.
--   This processor outputs the latest image from the camera at each
--   invocation.
camera :: Int -> ImageSource

-- | A window that displays images. Note: windows with the same index will
--   be the same window....is this ok?
window :: Int -> ImageSink

-- | A convenience function for constructing a common type of processors
--   that work exclusively on images
imageProcessor :: (Ptr IplImage -> Ptr IplImage -> IO (Ptr IplImage)) -> (Ptr IplImage -> IO (Ptr IplImage)) -> ImageProcessor

-- | OpenCV's cvResize
resize :: Int -> Int -> InterpolationMethod -> ImageProcessor

-- | OpenCV's cvDilate
dilate :: Int -> ImageProcessor

-- | OpenCV's cvCanny
canny :: Int -> Int -> Int -> ImageProcessor

-- | Wrapper for OpenCV's cvHaarDetectObjects and the surrounding required
--   things (mem storage, cascade loading, etc).
haarDetect :: String -> Double -> Int -> HaarDetectFlag -> CvSize -> Processor IO (Ptr IplImage) [CvRect]

-- | OpenCV's cvRectangle, currently without width, color or line type
--   control
drawRects :: Processor IO (Ptr IplImage, [CvRect]) (Ptr IplImage)