[vtkusers] Error when deleting a vtkImageData object !

[Dean Inglis]

Hi JD,

you created and deleted a vtkImageData when you dont need to.

    // Define vtk objects
    vtkBMPReader* m_ImageReader = vtkBMPReader::New();
//    vtkImageData* m_ImageData = vtkImageData::New();

Its ok to declare a pointer to a vtkImageData:

vtkImageData* m_ImageData = NULL;

    // Get data from image file

and ok to assign the pointer to the output of
a vtk (image) algorithm's output:

    m_ImageData = m_ImageReader->GetOutput();
    m_ImageData->Update();

    // Now do some cleaning
    m_ImageReader->Delete();

It is NOT ok to delete the output of a filter:

    m_ImageData->Delete(); //  Commenting this line  "solve" the error !

The vtkImageData output of the filter, in your case a reader, is maintained
by the reader itself.  When you delete the reader, its output
is also (eventually) deleted when any other pipeline objects
that are using it delete themselves.

Dean.


I'm having a problem when I'm deleting a vtkImageData object.
I obtain the following error message (located in 
vtkImageAlgorithm::Execute()) :
"Definition of Execute() method should be in subclass and you should 
really use the ExecuteData(vtkInformation *request,...) signature instead"

Up to now, I've found no other workaround than NOT deleting the object, 
which I'm obviously not really happy with.

Herebelow is a small sample code that reproduces the problem (I'm using 
vtk5.0.4 under MSVC++8).

Any idea where my mistake comes from?
JD.

    // Define vtk objects
    vtkBMPReader* m_ImageReader = vtkBMPReader::New();
    vtkImageData* m_ImageData = vtkImageData::New();
    vtkTexture* m_Texture = vtkTexture::New();

    // Read bmp file
    m_ImageReader->SetFileName("Image.bmp");
    // Get data from image file
    m_ImageData = m_ImageReader->GetOutput();
    m_ImageData->Update();
    // Assign data to texture
    m_Texture->SetInput(m_ImageData);
    m_Texture->Update();
    // Other stuff
    // ...
    // ...
    // Now do some cleaning
    m_ImageReader->Delete();
    m_ImageData->Delete(); //  Commenting this line  "solve" the error !
    m_Texture->Delete();