/*=========================================================================

  Program:   Visualization Toolkit
  Module:    vtkTreeOrbitLayoutStrategy.h
  
=========================================================================*/
/*----------------------------------------------------------------------------
 Copyright (c) Sandia Corporation
 See Copyright.txt or http://www.paraview.org/HTML/Copyright.html for details.
----------------------------------------------------------------------------*/
// .NAME vtkTreeOrbitLayoutStrategy - hierarchical orbital layout
//
// .SECTION Description
// Assigns points to the nodes of a tree to an orbital layout. Each parent
// is orbited by its children, recursively.

// .SECTION Thanks
// Thanks to the galaxy for inspiring this layout strategy.

#ifndef __vtkTreeOrbitLayoutStrategy_h
#define __vtkTreeOrbitLayoutStrategy_h

#include "vtkGraphLayoutStrategy.h"

class vtkPoints;
class vtkTree;


class VTK_INFOVIS_EXPORT vtkTreeOrbitLayoutStrategy : public vtkGraphLayoutStrategy 
{
public:
  static vtkTreeOrbitLayoutStrategy *New();

  vtkTypeRevisionMacro(vtkTreeOrbitLayoutStrategy, vtkGraphLayoutStrategy);
  void PrintSelf(ostream& os, vtkIndent indent);

  // Description:
  // Perform the orbital layout.
  void Layout();

  // Description:
  // The spacing of orbital levels. Levels near zero give more space
  // to levels near the root, while levels near one (the default)
  // create evenly-spaced levels. Levels above one give more space
  // to levels near the leaves.
  vtkSetMacro(LogSpacingValue, double);
  vtkGetMacro(LogSpacingValue, double);

  // Description:
  // The spacing of leaves.  Levels near one evenly space leaves
  // with no gaps between subtrees.  Levels near zero creates
  // large gaps between subtrees.
  vtkSetClampMacro(LeafSpacing, double, 0.0, 1.0);
  vtkGetMacro(LeafSpacing, double);
  
  // Description:
  // This is a magic number right now. Controls the radius
  // of the child layout, all of this should be fixed at
  // some point with a more logical layout. Defaults to .5 :)
  vtkSetMacro(ChildRadiusFactor, double);
  vtkGetMacro(ChildRadiusFactor, double);

protected:
  vtkTreeOrbitLayoutStrategy();
  ~vtkTreeOrbitLayoutStrategy();
  
  void OrbitChildren(vtkTree *t, vtkPoints *p, vtkIdType parent, double radius);

  double LogSpacingValue;
  double LeafSpacing;
  double ChildRadiusFactor;

private:

  vtkTreeOrbitLayoutStrategy(const vtkTreeOrbitLayoutStrategy&);  // Not implemented.
  void operator=(const vtkTreeOrbitLayoutStrategy&);  // Not implemented.
};

#endif

