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


-- | planar graph embedding into a plane
--   
--   A library realizes one of the graph visualization process's steps -
--   graph embedding into a plane. The job of the step is such to order
--   nodes' edges that there are capabilities to draw them without any
--   intersections.
@package gbu
@version 0.1


-- | additional functions for the graph structure defined in fgl library
module Data.Graph.InductivePlus

-- | the function updates a label of v node in the graph g
setVLabel :: (Node, a) -> a -> Gr a b -> Gr a b

-- | the function updates a label of v node in the graph g
setVLabel' :: Node -> a -> Gr a b -> Gr a b

-- | the function extracts a label of v node from the graph g
getVLabel :: Node -> Gr a b -> a
setELabel :: (Node, Node, a) -> a -> Gr b a -> Gr b a

-- | the function version of setELabel for an undirected graph
getELabel :: (Node, Node) -> Gr a b -> b
isEdge :: (Node, Node) -> Gr a b -> Bool

-- | the function merges two graphs. E.i. if first graph hasn't got vertex
--   v but second one has got it then the node is inserted into first graph
--   with same label. Edges are processed too.
mergeTwoGraphs :: Gr a b -> Gr a b -> Gr a b

-- | it finds and returns the path consiting of edges from first node to
--   second one. If the path doesn't exist then the function returns the
--   empty list.
findPaths :: Node -> Node -> Gr a b -> [Path]
instance (Eq a, Eq b) => Eq (Gr a b)


-- | Graph embedding algorithm is based on one of a graph planarity testing
--   which described in the book "Graph Drawing. Algorithms for the
--   Visualization of Graphs". Its authors are Giuseppe Di Battista, Peter
--   Eades, Roberto Tamassia and Ioannis G. Tollis.
module Data.Graph.Embedding

-- | The <a>embedGraph</a> function embeds a planar biconnected undirected
--   graph into a plane. Edge's label of an embedded graph is a position of
--   the edge in its source node.
--   
--   In undirected graph each edge is presented a pair of directed edges.
--   Therefore it's enough each edge keeps only its position in the source
--   node.
embedGraph :: Gr a b -> Gr a Int

-- | The <a>embedDiGraph</a> function embeds a planar directed graph into a
--   plane. The source graph must be biconnected if throw off edges'
--   directions and also any two nodes v and w can have either edge (v,w)
--   or (w,v) but not both.
--   
--   Edge's label of an embedded graph consists of a pair integers. First
--   element is a position of the edge in its source node and second one is
--   a position of the edge in its destination node.
embedDiGraph :: Gr a b -> Gr a (Int, Int)
instance Show Piece
instance Eq Piece
instance Show Side
instance Eq Side
instance Show C
instance Eq C
instance Show OldC
instance Eq OldC
instance Show EdgeLabel
instance Eq EdgeLabel
instance Ord Piece
instance Ord EdgeLabel