[vtkusers] Invoke "Interactor"-Event to vtkSphereWidget

[Eric E. Monson]

Hey Rocco,

Karthik means really invoking Render() on the widget itself, not the Interactor or Renderer. Although, I think he's referring to the newer Widget classes, and it looks like you are using the older ones. Have you tried using SphereWidget2? 

http://www.vtk.org/doc/nightly/html/classvtkSphereWidget2.html

The newer widgets separate out the event handling and the graphical representation in a nice way. There is a Tcl test listed on that page to show you how to use it, but you can also get some ideas from any of the other widgets which end in ...Widget2

Good luck,
-Eric

------------------------------------------------------
Eric E Monson
Duke Visualization Technology Group


On Jun 14, 2010, at 4:35 AM, Rocco Gasteiger wrote:

> Hi Karthik,
> 
> Thank you for your fast respond. I invoke the Render()-call in several ways
> but it was not successful.
> I tried the render call on the interactor of the widget as well as with the
> GetCurrentRenderer-method of the widget itself. But it doesn't help. I have
> to press the i-key again.
> 
> In my code below I added an observer to the widget renderer, listening to
> the vtkCommand::Start/EndEvent. If I called Render() in the associated
> vtkCommand-class I got a stack overflow exception because I step into a
> recursive render loop. So I removed the observer. 
> 
> What I've tried now is to add a pointer of my widget to my own interactor
> style. Every time, I double click on my scene object I process my own
> interactor behavior which also enables the sphere widget and calls the
> Render()-method like mentioned above. Here is a code snippet to illustrate
> this:
> 
> // in my main-class
> myMouseStyle->SetWidget(widget);
> 
> // in my derived style-class
> widget->SetEnabled(1);
> widget->SetHandleVisibility(1);
> widget->GetCurrentRenderer->Render();// Doesn't work
> this->Interactor->Render(); // Doesn't work
> 
> Do you have any reasons why it doesn't work? I have to mention that I use a
> QVTKWidget to display my vtk-scene. Can this have an influence on it?
> 
> Best regards, Rocco
> 
> -----Ursprüngliche Nachricht-----
> Von: Karthik Krishnan [mailto:karthik.krishnan at kitware.com] 
> Gesendet: Sonntag, 13. Juni 2010 11:43
> An: Rocco Gasteiger
> Betreff: Re: [vtkusers] Invoke "Interactor"-Event to vtkSphereWidget
> 
> You must invoke Render() explicitly on the widget after invoking SetEnabled.
> 
> Recently (roughly a year ago), the Render() call was removed from
> SetEnabled, so that multiple widgets could be enabled without
> triggering several renders.
> 
> 
> 
> On 6/12/10, Rocco Gasteiger <post at rocco-gasteiger.de> wrote:
>> Dear vtk-users,
>> 
>> 
>> 
>> I want to use a vtkSphereWidget in my scene to orient a geometry.
> Currently,
>> I have to press the key "i" to enable this widget (i.e. make the handle
>> visible). However, I want to enable this widget once the widget geometry
> is
>> shown in my render window. For this purpose I add an observer to my
> renderer
>> with the parameters "vtkCommand::StartEvent" and a derived class of
>> vtkCommand as callback-command. Additionally, I set a pointer to the
>> vtkSphereWidget in my derived callback-command. When the event is
> processed
>> (and I proved that this event is throwing!), I call  "SetEnabled(1)" in my
>> derived callback-command. However, the handle is not visible. I need to
>> press the "i"-key to make it visible. I also tried to add observers to the
>> interactor but the problem is still the same.
>> 
>> 
>> 
>> Can anybody give me a hint what I'm doing wrong?
>> 
>> 
>> 
>> Thanks in advance, Rocco
>> 
>> 
>> 
>> 
>> 
>> P.S. Here is a code snippet of what I'm doing currently:
>> 
>> 
>> 
>> // The main-class:
>> 
>> .
>> 
>> vtkSmartPointer<vtkSphereWidget> sphereWidget =
>> vtkSmartPointer<vtkSphereWidget>::New();
>> 
>> sphereWidget ->SetInteractor(windowInteractor);
>> 
>> sphereWidget ->SetCurrentRenderer(renderer);
>> 
>> sphereWidget ->SetEnabled(1);
>> 
>> sphereWidget ->SetHandleSize(0.03);
>> 
>> sphereWidget ->SetPhiResolution(20);
>> 
>> sphereWidget ->SetThetaResolution(20);
>> 
>> sphereWidget ->GetSphereProperty()->BackfaceCullingOn();
>> 
>> sphereWidget ->SetHandleVisibility(1);
>> 
>> .
>> 
>> 
>> 
>> vtkSmartPointer<vtkMyWidgetCallback> widgetCallback =
>> vtkSmartPointer<vtkMyWidgetCallback>::New();
>> 
>> widgetCallback->SetWidget(sphereWidget);
>> 
>> renderer->AddObserver(vtkCommand::StartEvent, widgetCallback);
>> 
>> 
>> 
>> // The derived vtkCommand class
>> 
>> class vtkMyWidgetCallback : public vtkCommand
>> 
>> {
>> 
>> public:
>> 
>>                static vtkMyWidgetCallback *New()
>> 
>>                {
>> 
>>                               return new vtkMyWidgetCallback;
>> 
>>                }
>> 
>> 
>> 
>>                virtual void Execute(vtkObject *caller, unsigned long,
>> void*)
>> 
>>                {
>> 
>> 
>> 
>> sphereWidget ->SetEnabled(1);
>> 
>>                               sphereWidget ->SetHandleVisibility(1);
>> 
>>                               cout << "Widget on!" << endl;
>> 
>>                }
>> 
>>                void SetWidget(vtkSphereWidget* widget);
>> 
>> 
>> 
>>                vtkSphereWidget* sphereWidget;
>> 
>> };
>> 
>> 
>> 
>> inline void vtkMyWidgetCallback::SetWidget(vtkSphereWidget* widget)
>> 
>> {
>> 
>>                sphereWidget = widget;
>> 
>> }
>> 
>> 
>> 
>> 
>> 
>> 
>> 
>> 
> 
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