[vtkusers] TimerEvents not fired while dragging mouse in vtkRenderWindow

Wed Nov 15 11:48:24 EST 2017

The interactor style may be doing a grab focus (which grabs all events
until the motion is done). Try putting some  printfs/breaks in the code
that generates the timerevent in vtk. Then maybe you can follow the event
and see who is consuming it etc,.

Or try commenting out all the GrabFocus() calls in the style you are using.

On Wed, Nov 15, 2017 at 11:42 AM, Kolja Petersen <petersenkolja at gmail.com>
wrote:

> No, this is on Linux. Maybe you can try the code snippet yourself to see
> what I am talking about? The problem is not, that the TimerEvents are
> slowed down during mouse interaction, they are dropped completely.
>
> How can the app be redesigned?
> First, I need the standard behaviour of vtkRenderWindowInteractor to allow
> rotating, zooming, panning.
> Second I need to update and redraw the scene repeatedly in constant
> intervals. Of course, I could trigger these events independent from VTK
> using a second thread. But these events need to operate on VTK objects from
> the main thread. Because VTK is not thread safe (which I have experienced
> by a number of segmentation faults when modifying VTK objects from
> different threads), I see absolutely no way to correctly process both 1)
> timer events and 2) user interaction events that block the timer events.
> Kolja
>
>
> <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail> Virenfrei.
> www.avast.com
> <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail>
> <#m_869865242780024731_DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>
>
> On Wed, Nov 15, 2017 at 5:25 PM, David Cole <DLRdave at aol.com> wrote:
>
>> 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()
>>>>
>>>>
>>>> <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail> Virenfrei.
>>>> www.avast.com
>>>> <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail>
>>>> <#m_869865242780024731_m_-7045443072964375499_m_-5995428116567439952_m_5020402281578617109_DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>
>>>>
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>>>
>>>
>>> --
>>> Ken Martin PhD
>>> Distinguished Engineer
>>> Kitware Inc.
>>> 28 Corporate Drive
>>> <https://maps.google.com/?q=28+Corporate+Drive+Clifton+Park+NY+12065&entry=gmail&source=g>
>>> Clifton Park NY 12065
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>>>
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>>
>> _______________________________________________
>> Powered by www.kitware.com
>>
>> Visit other Kitware open-source projects at
>> http://www.kitware.com/opensource/opensource.html
>>
>> Please keep messages on-topic and check the VTK FAQ at:
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>>
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>>
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>

-- 
Ken Martin PhD
Distinguished Engineer
Kitware Inc.
28 Corporate Drive
Clifton Park NY 12065

This communication, including all attachments, contains confidential and
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