[vtk-developers] undo / redo for vtkContourWidget + expose SelectedNodesCursorShape

[Dean Inglis]

Hi all,

I would like to add undo redo capability for vtkContourWidget.  The
implementation would be to have vtkContourRepresentation's internals
modified as follows:
1) add Copy methods to the vtkContourRepresentationNode:

  void Copy( vtkContourRepresentationNode* node )
  {
    vtkstd::vector< vtkContourRepresentationPoint* > points = node->Points;
    vtkstd::vector< vtkContourRepresentationPoint* >::iterator it1, it2;

    memcpy( this->WorldPosition, node->WorldPosition, 3 * sizeof( double )
);
    memcpy( this->WorldOrientation, node->WorldOrientation, 9 * sizeof(
double ) );
    memcpy( this->NormalizedDisplayPosition,
node->NormalizedDisplayPosition, 2 * sizeof( double ) );
    this->Selected = node->Seleced;

    this->Points.resize( points.size() );
    for( it1 = points.begin(), it2 = this->Points.begin();
         it1 != points.end() && it2 != this->Points.end();
         it1++, it2++ )
    {
      ( *it2 ) = new vtkContourRepresentationPoint;
      memcpy( ( *it2 )->WorldPosition, ( *it1 )->WorldPosition,
        3 * sizeof( double ) );
      memcpy( ( *it2 )->NormalizedDisplayPosition, ( *it1
)->NormalizedDisplayPosition,
        2 * sizeof( double ) );
    }
  }

and the vtkContourRepresentationInternals:

  void Copy( vtkContourRepresentationInternals* internal )
  {
    vtkstd::vector< vtkContourRepresentationNode* > nodes = internal->Nodes;
    vtkstd::vector< vtkContourRepresentationNode* >::iterator it1, it2;

    this->Nodes.resize( nodes.size() );
    for( it1 = nodes.begin(), it2 = this->Nodes.begin();
         it1 != nodes.end() && it2 != this->Nodes.end();
         it1++, it2++ )
    {
      ( *it2 ) = new vtkContourRepresentationNode;
      ( *it2 )->Copy( *it1 );
    }
  }

and implement the following:

  // Description:
  // Records the current layout of nodes adding them to the node history
list
  // so that they can be undone/redone.
  virtual void TakeSnapshot();

  // Description:
  // A history of changes to the layout of nodes is kept internally and
  // externally by calling TakeSnapshot().
  // These two methods are used to go back to earlier changes to the contour
  // or return to more recent ones.
  virtual void Undo();
  virtual void Redo();

  // Description:
  // Methods to determine whether there is any history left to undo or redo.
  virtual int CanUndo();
  virtual int CanRedo();

by maintaining protected members:

//BTX
  vtkstd::vector< vtkContourRepresentationInternals* >
InternalHistory;
  vtkstd::vector< vtkContourRepresentationInternals* >::iterator
InternalHistoryIterator;
//ETX

Also, can the SelectedNodesCursorShape be exposed through the public API
of vtkOrientedGlyphContourRepresentation as is done for SetCursorShape and
SetActiveCursorShape ?

Dean