[Insight-users] how to connect the observer message to the GUI?

[Luis Ibanez]

Hi Joris,

Your current problem is not related with ITK at all.

It seems to be a misunderstanding of the way you pass
values in C++ (by value, reference or pointers).

Unfortunately you are not 'connecting' the string from
the observer to the string of your MFC GUI.

Your Execute() method is simply filling in the content of
m_TextOutput which is a member variable of the observer,
and in no way is updating the content of the GUI.

You may have to modify your Command/Observer in order to
have a pointer or a reference to the GUI components that
you want to update.  In that way, the last step of the
Execute method will be to modify the GUI element, and then
refresh the output.

You may add a pointer to the top element of your GUI
so inside the Execute method you could write something
like:



Execute()
   {
    ...
   ...
   *m_CStringOut = m_TextOutput;
   ((CMainFrame *)AfxGetMainWnd())->RedrawWindow();
   } // end of Execute.

  SetString( CString * realString )
  {
   m_CStringOut = realString;
  }

private:
  CString * m_CStringOut ;
}; // end of Class Observer




Luis


------------

J Mst wrote:
> Hi all,
> 
> I think I've to simplify my question. I will clarify my problem with 
> some code. I'll post a snippet of the commanIterationUpdate class and of 
> the use of that class in my application. First the 
> CommandIterationUpdate class:
> 
> ******************************************************************************* 
> 
> #ifndef __itkCommandIterationUpdate_h
> #define __itkCommandIterationUpdate_h
> 
> #include <itkCommand.h>
> #include "itkWeakPointer.h"
> 
> namespace itk {
> 
> template < class TOptimizer >
> class ITK_EXPORT CommandIterationUpdate : public Command
> {
> public:
>  typedef CommandIterationUpdate   Self;
>  typedef itk::Command  Superclass;
>  typedef itk::SmartPointer<Self>  Pointer;
>  typedef itk::SmartPointer<const Self>  ConstPointer;
> 
>  void Execute(itk::Object *caller, const itk::EventObject & event)
>  {
>    Execute( (const itk::Object *)caller, event);
>  }
> 
>  void Execute(const itk::Object *caller, const itk::EventObject & event)
>  {
>    if( typeid( event ) == typeid( itk::IterationEvent ) )
>      {
> 
>      //std::cout << m_Optimizer->GetCurrentIteration() << " = ";       
> //This is the method used !!!!
>      //std::cout << m_Optimizer->GetValue() << " : 
> ";                       //   in the registration      !!!!!
>      //std::cout << m_Optimizer->GetCurrentPosition() << std::endl;   
> //           examples          !!!!!
> 
>     std::StringStream text;
>     text <<  m_Optimizer->GetCurrentIteration() << " : " << ;
>     text <<  m_Optimizer->GetValue() << " : " <<;
>     text <<  m_Optimizer->GetCurrentPosition() << std::endl;
>     m_TextOut = text.str().c_str();
>      }
>  }
> 
> itkTypeMacro( CommandIterationUpdate, ::itk::Command );
> itkNewMacro( Self );
> typedef    TOptimizer     OptimizerType;
> 
> void SetOptimizer( OptimizerType * optimizer )
>    {
>    m_Optimizer = optimizer;
>    m_Optimizer->AddObserver( itk::IterationEvent(), this );
>    }
> 
> void SetOutput( CString m_Out )
> {
>     m_Out = m_TextOut;
> }
> 
> protected:
> 
> 
>  CommandIterationUpdate() {};
> 
> private:
> 
>  WeakPointer<OptimizerType>   m_Optimizer;
> 
>  CString            m_TextOut;
> 
> };
> }
> #endif
> ******************************************************************************** 
> 
> 
> As can be seen, I've put the update message into a stream and I want 
> that stream te be seen in the GUI. Therefore I created the funtion 
> SetOutput. I've used this class in the following way.
> 
> ****************ApplicationDlg.h******************
> 
> typedef    CommandIterationUpdate<OptimizerType>   IterationObserverType;
> 
> IterationObserverType::Pointer      m_observer;
> 
> ***************************************************
> 
> ***************ApplicationDlg.cpp*******************
> 
> m_observer = IterationObserverType::New();
> 
> 
> void ApplicationDlg::onStartRegistration()
> {
> 
> m_observer->SetOptimizer( RegularStepOptimizer );
> m_observer->SetOutput( m_TextOutput );
> 
> m_registration->StartRegistration();
> }
> **************************************************
> 
> The m_TextOutput variavbe is connected to the edit box in my GUI, and 
> with the funtion SetOutput() I hoped to connect the output of the 
> CommandIterationUpdate class to the GUI. But this didn't work 
> unfortunately.
> 
> Does someone know what I am doing wrong? Or is there a easier way do do 
> the thing that I want??
> 
> Thanks in advance.
> 
> Joris
> 
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