[IGSTK-Users] igstk::QView and registration applications

[Luis Ibanez]

Hi Torleif,

The behavior that you observe in the igstkView2D (that is
actually defined in the igstkView class), it is not yet
defined in the igstkQView class.

To be more precise:


1) For the Observer of the TransformModifiedEvent to work,
    the View class must invoke a TransformModifiedEvent from
    the interaction that listens to the mouse click on the GUI.
    In the case of the View class this is done in the method:

                       View::handle()

    in lines 835-857.


2) The equivalent code in the QView is performed at the
    level of the vtkQWidget class in:

            VTK/GUISupport/Qt/QVTKWidget.cxx

    in line 601: method    QVTKWidget::mouseReleaseEvent()


    The management of the left mouse release event is made in
    lines : 628-630:

    case Qt::LeftButton:
       iren->InvokeEvent(vtkCommand::LeftButtonReleaseEvent, e);
       break;


3) One way of solving this issue is to add to the QView class
    an overloaded implementation of the method:

             mouseReleaseEvent(QMouseEvent* e)

    and insert in the case statement for LeftButton the code
    that uses a Picker for sending the TransformModifiedEvent
    out to any potential observers. We must also add to the
    QView the vtkWorldPointPicker as a member variable.


    Please note that all these changes will be regrouped when
    the View class is refactored in order to unify the FLTK
    and the Qt implementations.



    Regards,



        Luis




-----------------------
Torleif Sandnes wrote:
> Hi.
> 
> I want to be able to do patient registration, and will ned a way to  get 
> image coordinates from user mouseclicks in my igstk::QView2D.
> If I Understand Correctly, the Needlebiopsy example does this in  
> DrawPickedPoint(const itk::Event& event), so I tried to do something  
> like this:
> 
> 1. In my class definition:
> typedef itk::ReceptorMemberCommand<Self> ObserverType;
> ObserverType::Pointer mTransformObserver;
> 
> 2. In my class constructor:
> mTransformObserver = ObserverType::New();
> mTransformObserver->SetCallbackFunction(this,  
> &MyClass::handleTransformEvent);
> 
> 3. After loading a Dicom image and showing it in an igstk::QView2D:
> mAxialViewWidget->AddObserver(igstk::TransformModifiedEvent(),  
> mTransformObserver);
> 
> 4. Finally, I created the function MyClass:handleTransformEvent():
> void MyClass::handleTransformEvent(const itk::EventObject& event)
> {
>     cout << "Transform event received: ";
> }
> 
> Unfortunately, I fail to see any output from this function.
> 
> Am I entirely off the rails with this approach?
> Is there a(n) (IGSTK) way to accomplish this?
> 
> Regards,
> Torleif Sandnes
> Sintef Health Research
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