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.
embedGraph 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.
embedDiGraph 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.