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The Planarization Method ( PlanarizationLayout )

Baseclasses

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Definition

The class PlanarizationLayout represents a general framework for drawing graphs with planarization. It applies a planarization module in order to transform a general graph into a planar graph by introducing dummy vertices at edge crossings, and draws the resulting planar graph using a layout algorithm for planar graphs. The planarization and planar layout algorithms are exchangeable modules allowing to use PlanarizationLayout with different methods for planarization and planar drawing.

General Information

Algorithm

name Planarization

long name Planarization

author

Implementation

author C. Gutwenger

date December 1997

version 1.0

Pre- and Postcondition

precondition = { noselfloops } $\cup$ (Pre_L $\cap$ {simple, four - graph, connected}

postcondition(PRE) = $\emptyset$

where Pre_L is the precondition of the planar_layouter module.

Exchangeable Modules Instances of type PlanarizationLayout provide the following module options:

$\bullet$

planarizer
a PlanarizerModule option used to compute the planarization of the input graph.

guaranteed precondition: { noselfloops, directed }

required postcondition: { planar, noselfloops }

initial module: PlanarSubgraph

$\bullet$

planar_layouter
a LayoutModule option used to draw the planarized graph.

guaranteed precondition: { planar, simple, noselfloops, connected, four - graph }

required postcondition: (PlaneGraphCopy - callable,{ nocrossings })

initial module: QuasiOrthogonalLayout

#include < AGD/PlanarizationLayout.h >

Creation

PlanarizationLayout L creates an instance L of type PlanarizationLayout.

Operations

int L.number_of_crossings() returns the number of crossings in the layout produced by a preceding call.

Standard Interface (Inherited Methods) The detailed description of these methods can be found in the manual entries of the base class (LayoutModule).

bool L.check(const graph& G, AgdKey& p)

void L.call(const graph& G, LayoutInterface& A)

Access to Options

bool L.set_planar_layouter(const LayoutModule& M)

bool L.set_planarizer(const PlanarizerModule& M)

Next: Planarization on the Grid Up: Planarization-Based Layout Methods Previous: Planarization-Based Layout Methods Contents Index

Algorithm
name	Planarization
long name	Planarization
author

Implementation
author	C. Gutwenger
date	December 1997
version	1.0

precondition	=	{ noselfloops } $\cup$ (Pre_L $\cap$ {simple, four - graph, connected}
postcondition(PRE)	=	$\emptyset$

guaranteed precondition:	{ noselfloops, directed }
required postcondition:	{ planar, noselfloops }
initial module:	PlanarSubgraph

guaranteed precondition:	{ planar, simple, noselfloops, connected, four - graph }
required postcondition:	(PlaneGraphCopy - callable,{ nocrossings })
initial module:	QuasiOrthogonalLayout

bool	L.check(const graph& G, AgdKey& p)
void	L.call(const graph& G, LayoutInterface& A)

bool	L.set_planar_layouter(const LayoutModule& M)
bool	L.set_planarizer(const PlanarizerModule& M)