[Paraview] Accessing VTK data from a Paraview plugin

[Miron Sadziak]

Hi

I want to write a plugin for Paraview to manipulate the data Paraview
has opened.
It will be mostly ImageData or PolyData but I would like to understand
the general idea how to do it.
Im using C++ so the code i have figured out by now looks like that:

#Getting the active source
pqApplicationCore* core = pqApplicationCore::instance();
pqServerManagerSelection sels = *core->getSelectionModel()->selectedItems();
pqPipelineSource* source = 0;
pqServerManagerModelItem* item = 0;
pqServerManagerSelection::ConstIterator iter = sels.begin();
item = *iter;
source = dynamic_cast<pqPipelineSource*>(item);

#Trying to access the data of the source.
#Here I can access data information only, not raw-data
vtkPVDataInformation*
datainfo=source->getOutputPort(0)->getDataInformation(true);
cout << "PointsNumber " << datainfo->GetNumberOfPoints() << "\n";
cout << "DataClassName " << datainfo->GetDataClassName() << "\n";

It all works but its just data information.
I would like to access a function like GetData or GetDataArray to be
able to read the data contained in the VTK object. To read/write
directly from/to the data array. The problem is that I cant find a
suitable function in any of the classes like pqPipelineSource,
vtkPVDataInformation etc.
What should I do ?

I would be thankful for any help,
Paraview user