I made a change on VtkImageViewer / QVtkWidget, but nothing happened until I click on it or do other things

Something like this

• http://vtk.1045678.n5.nabble.com/Help-updating-a-QVTKWidget-td1227414.html

Solution :

• Whenever you make changes to VTK's data objects it's your job to call qvtkWidget->update() or viewer->Render() afterward so the new changes get put onto the screen.

The most convenient way is to call the Render( ) method of VtkImageViewer

• When you change the vtkImageData which is the VtkImageViewer's Input
• When you need to change the showing slice( most of time is a 3D Data )  
• Blah, blah

---------> Call Render( )