VTK: how can I add a scrollbar to my project?

What's the easiest way to add a scrollbar to my VTK project ?

thanks

Update

def vtkSliderCallback2(obj, event):
    sliderRepres = obj.GetRepresentation()
    pos = sliderRepres.GetValue()
    contourFilter.SetValue(0, pos)

SliderRepres = vtk.vtkSliderRepresentation2D()
min = 0 #ImageViewer.GetSliceMin()
max = 256 #ImageViewer.GetSliceMax()
SliderRepres.SetMinimumValue(min)
SliderRepres.SetMaximumValue(max)
SliderRepres.SetValue((min + max) / 2)
SliderRepres.SetTitleText("Slice")
SliderRepres.GetPoint1Coordinate().SetCoordinateSystemToN开发者_StackOverflow社区ormalizedDisplay()
SliderRepres.GetPoint1Coordinate().SetValue(0.2, 0.6)
SliderRepres.GetPoint2Coordinate().SetCoordinateSystemToNormalizedDisplay()
SliderRepres.GetPoint2Coordinate().SetValue(0.4, 0.6)

SliderRepres.SetSliderLength(0.02)
SliderRepres.SetSliderWidth(0.03)
SliderRepres.SetEndCapLength(0.01)
SliderRepres.SetEndCapWidth(0.03)
SliderRepres.SetTubeWidth(0.005)
SliderRepres.SetLabelFormat("%3.0lf")
SliderRepres.SetTitleHeight(0.02)
SliderRepres.SetLabelHeight(0.02)

SliderWidget = vtk.vtkSliderWidget()
SliderWidget.SetInteractor(iren)
SliderWidget.SetRepresentation(SliderRepres)
SliderWidget.KeyPressActivationOff()
SliderWidget.SetAnimationModeToAnimate()
SliderWidget.SetEnabled(True)
SliderWidget.AddObserver("InteractionEvent", vtkSliderCallback2)

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Just to be complete and for other users googling thing.

vtkSliderWidget will do what you want if you need it to set a value.

//edit based on your edit If you want to get the value, you have to connect an event to the slider which is fired when the value is changed. Than retrieve this value and update accordingly. An example in C++ is found here

// I actually think my issue is that the callback function is invoked for each thumb position when I slide it. How can avoid that ? In other words I only want the last position to trigger the callback function...

Try coupling it to the EndInteractionEvent instead of to the InteractionEvent.

SliderWidget.AddObserver("EndInteractionEvent", vtkSliderCallback2)

// stuff

By the way, if you use python and VTK and need GUI stuff, I advice you to use the python QT and python qt widgets which ease up alot of this stuff. Some code of one of my old projects using QT+Python+VTK for GUI + python stuff:

self.verticalSlider = QtGui.QSlider(self.centralwidget)
self.verticalSlider.setOrientation(QtCore.Qt.Vertical)
self.verticalSlider.setObjectName("verticalSlider")
self.horizontalLayout.addWidget(self.verticalSlider)

// connect slider to a method onValueChange
QObject.connect(self.verticalSlider, SIGNAL("valueChanged(int)"), 
self.setFibreVolumeOpacity)

def setFibreVolumeOpacity(self, value):
    // do stuff here with slider value.