[vtkusers] TimerEvents not fired while dragging mouse in vtkRenderWindow

[David Cole]

Is this on Windows? WM_TIMER events are notorious for not firing frequently when lots of other user events are also happening. If the mouse is captured, they may not fire at all. This is not something unique to VTK, it happens with just any Windows program.

You may need to consider redesigning a bit of your app if you must have code being executed regularly even during user interactions.


David

> On Nov 15, 2017, at 5:26 AM, Kolja Petersen <petersenkolja at gmail.com> wrote:
> 
> I replaced the line "iren.AddObserver(vtk.vtkCommand.TimerEvent,observer)" with
> iren.AddObserver(vtk.vtkCommand.TimerEvent,observer,100000.) (also tried 10.0 instead of 100000.)
> 
> Still no TimerEvents are reported as long as the mouse button is pressed.
> 
> How are events consumed? My understanding is that AddObserver(...) adds just another listener, and that all listeners registered for a specific event are invoked one after the other. Which function would "consume" events in an interactor style? Is it possible to circumvent the consuming of events, or to re-emit the event after it has been consumed?
> Thank you
> Kolja
> 
> 
>> On Tue, Nov 14, 2017 at 5:53 PM, Ken Martin <ken.martin at kitware.com> wrote:
>> I suspect timer events are fired but something else is consuming them. Probably in the interactor style. Try adding your timer events with a higher priority like 10.0 (third argument).
>> 
>>> On Mon, Nov 13, 2017 at 3:21 PM, Kolja Petersen <petersenkolja at gmail.com> wrote:
>>> Heya,
>>> I paste some code below, which displays an empty vtkRenderWindow with an interactor. The interactor fires a TimerEvent every 100ms as printed by the Observer.
>>> The problem: as long as I press a mouse button in the vtkRenderWindow, the TimerEvents stop to be reported, although I need to process data periodically in my application as a reaction to those TimerEvents.
>>> 
>>> Why are no TimerEvents fired while a button is pressed, and how can I change this behaviour?
>>> Thank you
>>> Kolja
>>> 
>>> import vtk
>>> 
>>> class Observer(object):
>>>   def __init__(self):
>>>     self.cnt=0
>>>   def __call__(self,caller,evt):
>>>     self.cnt+=1
>>>     print "count %d %s" % (self.cnt,evt)
>>> 
>>> ren1 = vtk.vtkRenderer()
>>> ren1.SetBackground(0.1, 0.2, 0.4)
>>> 
>>> renWin = vtk.vtkRenderWindow()
>>> renWin.AddRenderer(ren1)
>>> renWin.SetSize(300, 300)
>>> 
>>> iren = vtk.vtkRenderWindowInteractor()
>>> iren.SetRenderWindow(renWin)
>>> 
>>> style = vtk.vtkInteractorStyleTrackballCamera()
>>> iren.SetInteractorStyle(style)
>>> 
>>> iren.Initialize()
>>> observer=Observer()
>>> iren.AddObserver(vtk.vtkCommand.TimerEvent,observer)
>>> iren.AddObserver(vtk.vtkCommand.MouseMoveEvent,observer)
>>> iren.AddObserver(vtk.vtkCommand.InteractionEvent,observer)
>>> iren.CreateRepeatingTimer(100)
>>> iren.Start()
>>> 
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>>> 
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>> 
>> 
>> 
>> -- 
>> Ken Martin PhD
>> Distinguished Engineer
>> Kitware Inc.
>> 28 Corporate Drive
>> Clifton Park NY 12065
>> 
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> 
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