PlanarDrawing< Graph > Class Template Reference
[Planarity Embedding and Drawing]

---

Detailed Description

template<typename Graph>
class lemon::PlanarDrawing< Graph >

The planar drawing algorithm calculates positions for the nodes in the plane. These coordinates satisfy that if the edges are represented with straight lines, then they will not intersect each other.

Scnyder's algorithm embeds the graph on an (n-2)x(n-2) size grid, i.e. each node will be located in the [0..n-2]x[0..n-2] square. The time complexity of the algorithm is O(n).

See also:

PlanarEmbedding

#include <lemon/planarity.h>

List of all members.

Public Types
typedef dim2::Point< int >	Point
	The point type for storing coordinates.
typedef Graph::template NodeMap< Point >	PointMap
	The map type for storing the coordinates of the nodes.
Public Member Functions
	PlanarDrawing (const Graph &graph)
	Constructor.
bool	run ()
	Calculate the node positions.
template<typename EmbeddingMap >
void	run (const EmbeddingMap &embedding)
	Calculate the node positions according to a combinatorical embedding.
Point	operator[] (const Node &node) const
	The coordinate of the given node.
const PointMap &	coords () const
	Return the grid embedding in a node map.

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Constructor & Destructor Documentation

PlanarDrawing

(

const Graph &

graph

)

[inline]

Constructor

Precondition:

The graph must be simple, i.e. it should not contain parallel or loop arcs.

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Member Function Documentation

bool run

(

)

[inline]

This function calculates the node positions on the plane.

Returns:

true if the graph is planar.

void run

(

const EmbeddingMap &

embedding

)

[inline]

This function calculates the node positions on the plane. The given embedding map should contain a valid combinatorical embedding, i.e. a valid cyclic order of the arcs. It can be computed using PlanarEmbedding.

Point operator[]

(

const Node &

node

)

const [inline]

This function returns the coordinate of the given node.

const PointMap& coords

(

)

const [inline]

This function returns the grid embedding in a node map of dim2::Point<int> coordinates.