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vtkSpanTreeLayoutStrategy Class Reference

#include <vtkSpanTreeLayoutStrategy.h>

Inheritance diagram for vtkSpanTreeLayoutStrategy:
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Collaboration diagram for vtkSpanTreeLayoutStrategy:
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Public Types

typedef vtkGraphLayoutStrategy Superclass
 
- Public Types inherited from vtkGraphLayoutStrategy
typedef vtkObject Superclass
 

Public Member Functions

virtual int IsA (const char *type)
 
vtkSpanTreeLayoutStrategyNewInstance () const
 
void PrintSelf (ostream &os, vtkIndent indent)
 
void Layout ()
 
virtual void SetDepthFirstSpanningTree (bool)
 
virtual bool GetDepthFirstSpanningTree ()
 
virtual void DepthFirstSpanningTreeOn ()
 
virtual void DepthFirstSpanningTreeOff ()
 
- Public Member Functions inherited from vtkGraphLayoutStrategy
vtkGraphLayoutStrategyNewInstance () const
 
void PrintSelf (ostream &os, vtkIndent indent)
 
virtual void SetGraph (vtkGraph *graph)
 
virtual void Initialize ()
 
virtual int IsLayoutComplete ()
 
virtual void SetWeightEdges (bool state)
 
virtual bool GetWeightEdges ()
 
virtual void SetEdgeWeightField (const char *field)
 
virtual char * GetEdgeWeightField ()
 

Static Public Member Functions

static vtkSpanTreeLayoutStrategyNew ()
 
static int IsTypeOf (const char *type)
 
static vtkSpanTreeLayoutStrategySafeDownCast (vtkObjectBase *o)
 
- Static Public Member Functions inherited from vtkGraphLayoutStrategy
static int IsTypeOf (const char *type)
 
static vtkGraphLayoutStrategySafeDownCast (vtkObjectBase *o)
 

Protected Member Functions

virtual vtkObjectBase * NewInstanceInternal () const
 
 vtkSpanTreeLayoutStrategy ()
 
 ~vtkSpanTreeLayoutStrategy ()
 
- Protected Member Functions inherited from vtkGraphLayoutStrategy
 vtkGraphLayoutStrategy ()
 
 ~vtkGraphLayoutStrategy ()
 

Protected Attributes

vtkGraphLayoutStrategyTreeLayout
 
bool DepthFirstSpanningTree
 
- Protected Attributes inherited from vtkGraphLayoutStrategy
vtkGraphGraph
 
char * EdgeWeightField
 
bool WeightEdges
 

Detailed Description

vtkSpanTreeLayout is a strategy for drawing directed graphs that works by first extracting a spanning tree (more accurately, a spanning forest), and using this both to position graph vertices and to plan the placement of non-tree edges. The latter are drawn with the aid of edge points to produce a tidy drawing.

The approach is best suited to "quasi-trees", graphs where the number of edges is of the same order as the number of nodes; it is less well suited to denser graphs. The boolean flag DepthFirstSpanningTree determines whether a depth-first or breadth-first strategy is used to construct the underlying forest, and the choice of strategy affects the output layout significantly. Informal experiments suggest that the breadth-first strategy is better for denser graphs.

Different layouts could also be produced by plugging in alternative tree layout strategies. To work with the method of routing non-tree edges, any strategy should draw a tree so that levels are equally spaced along the z-axis, precluding for example the use of a radial or balloon layout.

vtkSpanTreeLayout is based on an approach to 3D graph layout first developed as part of the "tulip" tool by Dr. David Auber at LaBRI, U.Bordeaux: see www.tulip-software.org

This implementation departs from the original version in that: (a) it is reconstructed to use Titan/VTK data structures; (b) it uses a faster method for dealing with non-tree edges, requiring at most two edge points per edge (c) allows for plugging in different tree layout methods (d) allows selection of two different strategies for building the underlying layout tree, which can yield significantly different results depending on the data.

Thanks:
Thanks to David Duke from the University of Leeds for providing this implementation.
Examples:
vtkSpanTreeLayoutStrategy (Examples)

Definition at line 70 of file vtkSpanTreeLayoutStrategy.h.

Member Typedef Documentation

Definition at line 75 of file vtkSpanTreeLayoutStrategy.h.

Constructor & Destructor Documentation

vtkSpanTreeLayoutStrategy::vtkSpanTreeLayoutStrategy ( )
protected
vtkSpanTreeLayoutStrategy::~vtkSpanTreeLayoutStrategy ( )
protected

Member Function Documentation

static vtkSpanTreeLayoutStrategy* vtkSpanTreeLayoutStrategy::New ( )
static
static int vtkSpanTreeLayoutStrategy::IsTypeOf ( const char *  type)
static
virtual int vtkSpanTreeLayoutStrategy::IsA ( const char *  type)
virtual

Reimplemented from vtkGraphLayoutStrategy.

static vtkSpanTreeLayoutStrategy* vtkSpanTreeLayoutStrategy::SafeDownCast ( vtkObjectBase *  o)
static
virtual vtkObjectBase* vtkSpanTreeLayoutStrategy::NewInstanceInternal ( ) const
protectedvirtual

Reimplemented from vtkGraphLayoutStrategy.

vtkSpanTreeLayoutStrategy* vtkSpanTreeLayoutStrategy::NewInstance ( ) const
void vtkSpanTreeLayoutStrategy::PrintSelf ( ostream &  os,
vtkIndent  indent 
)
virtual void vtkSpanTreeLayoutStrategy::SetDepthFirstSpanningTree ( bool  )
virtual

If set, base the layout on a depth-first spanning tree, rather than the default breadth-first spanning tree. Switching between DFT and BFT may significantly change the layout, and choice must be made on a per-graph basis. Default value is off.

virtual bool vtkSpanTreeLayoutStrategy::GetDepthFirstSpanningTree ( )
virtual

If set, base the layout on a depth-first spanning tree, rather than the default breadth-first spanning tree. Switching between DFT and BFT may significantly change the layout, and choice must be made on a per-graph basis. Default value is off.

virtual void vtkSpanTreeLayoutStrategy::DepthFirstSpanningTreeOn ( )
virtual

If set, base the layout on a depth-first spanning tree, rather than the default breadth-first spanning tree. Switching between DFT and BFT may significantly change the layout, and choice must be made on a per-graph basis. Default value is off.

virtual void vtkSpanTreeLayoutStrategy::DepthFirstSpanningTreeOff ( )
virtual

If set, base the layout on a depth-first spanning tree, rather than the default breadth-first spanning tree. Switching between DFT and BFT may significantly change the layout, and choice must be made on a per-graph basis. Default value is off.

void vtkSpanTreeLayoutStrategy::Layout ( )
virtual

Perform the layout.

Implements vtkGraphLayoutStrategy.

Member Data Documentation

vtkGraphLayoutStrategy* vtkSpanTreeLayoutStrategy::TreeLayout
protected

Definition at line 95 of file vtkSpanTreeLayoutStrategy.h.

bool vtkSpanTreeLayoutStrategy::DepthFirstSpanningTree
protected

Definition at line 96 of file vtkSpanTreeLayoutStrategy.h.


The documentation for this class was generated from the following file: