[vtkusers] Segfault when using vtkSmartPointer<vtkImageViewer2> in a QVTKWidget

[t1m]

Hello,

 I have a problem with a vtkImageViewer2 instance in a QVTKWidget.  It looks
like it has to do with the use of a vtkSmartPointer.

To illustrate the problem, I wrote the following code: 

----- main.cpp ------ 
#include <qapplication.h>

#include <QString>
#include <QFileDialog>
#include <QObject>

#include <QVTKWidget.h>

#include <vtkTIFFReader.h>
#include <vtkImageViewer2.h>
#include <vtkRenderWindow.h>
#include <vtkSmartPointer.h>
#include <vtkImageActor.h>

int 
main(int argv, char ** argc) 
{ 
    QApplication app(argv, argc); 
    QVTKWidget * tdisplay = new QVTKWidget(); 

    //app.setMainWidget(tdisplay); 
    QString m_imageFileName =
QFileDialog::getOpenFileName(tdisplay,QObject::tr("Open
Image"),"",QObject::tr("*.tif *.tiff")); 

    std::cout << "m_imageFileName = " << m_imageFileName.toStdString() <<
std::endl; 

    if(!m_imageFileName.isEmpty()) { 
        vtkSmartPointer<vtkTIFFReader> vtkReader =
vtkSmartPointer<vtkTIFFReader>::New(); 
        vtkReader->SetFileName(m_imageFileName.toStdString().c_str()); 
        vtkReader->Update(); 

        vtkSmartPointer<vtkImageViewer2> image_view =
vtkSmartPointer<vtkImageViewer2>::New(); 
        image_view->SetInput(vtkReader->GetOutput()); 

        image_view->GetImageActor()->InterpolateOff(); 
        image_view->SetColorLevel(127); 
        image_view->SetColorWindow(255); 
            
       
image_view->SetupInteractor(tdisplay->GetRenderWindow()->GetInteractor()); 
        image_view->SetRenderWindow(tdisplay->GetRenderWindow()); 
        tdisplay->show(); 
    } 

    app.exec(); 
} 
----- end of main.cpp ------ 

you can compile this with a short qt project file (change the INCLUDEPATH
and LIBS accordingly): 

----- testQVTK.pro ----- 
TEMPLATE = app 
TARGET = 
DEPENDPATH += . 
INCLUDEPATH += . 

CONFIG += qt opengl debug 

# Input 
SOURCES += vtkTest.cpp 

INCLUDEPATH += /usr/local/include/vtk-5.8 

LIBS += -L/usr/local/lib/vtk-5.8 -lQVTK -lvtkRendering -lvtkCommon -lvtkIO
-lvtkFiltering 
----- end of testQVTK.pro ----- 

qmake; make; 

fire up the programm, choose a tiff image and click into the window.  It
crashes in both of my environments (Debian GNU/Linux amd64 and Mac OS X
10.6.8) with a segmentation fault. 

So I debugged it, and (most of the time) it crashes at this line in the
function vtkImageViewer2Callback::Execute(): 
469           if (this->IV->GetInput() == NULL) 

The strange thing is, that IV indeed points to the Object allocated in the
image_viewer vtkSmartPointer.  But examining it further, I could see that
e.g. the RenderWindow pointer inside the vtkImageViewer2 pointer changes
after the call to app.exec(). 

So I tried a simple C++ pointer (vtkImageViewer2::New()) instead of the
vtkSmartPointer of vtkImageViewer2, and the problem vanished! 

My question now is:  Did I do sth wrong with the use of vtkSmartPointer, or
is this a bug? 

I appreciate any help, 

   cheers, 

     Tim

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