VTK with Qt5 - Timer stops running when window is interacted with

Question

I\'ve been trying to do animation with VTK, so I\'ve been using TimerEvent. When I tried to move over to the Qt binding, it broke. The problem is that as soon as I interact wit

Answer 1

The problem is reproducible in Linux 16.04, VTK8.1.1 and Qt5.5.1.

As you are using Qt, a workaround for your problem is to use QTimer(). It is a solution if you want to work with a timing.

This is your minimal example changing the TimerEvent for QTimer():

import vtk
from vtk.qt.QVTKRenderWindowInteractor import QVTKRenderWindowInteractor
from PyQt5 import Qt
from PyQt5.QtCore import QTimer

message = "tick"
def onTimerEvent():
    global message
    print(message)
    if message == "tick":
        message = "tock"
    else:
        message = "tick"

app = Qt.QApplication([])
mainWindow = Qt.QMainWindow()
renderer = vtk.vtkRenderer()
vtkWidget = QVTKRenderWindowInteractor(mainWindow)
vtkWidget.GetRenderWindow().AddRenderer(renderer)
mainWindow.setCentralWidget(vtkWidget)

vtkWidget.GetRenderWindow().GetInteractor().Initialize()
#timerId = vtkWidget.CreateRepeatingTimer(100)
#vtkWidget.AddObserver("TimerEvent", onTimerEvent)
timer = QTimer()
timer.timeout.connect(onTimerEvent)
timer.start(100)
mainWindow.show()
app.exec_()