[vtkusers] Strange segfault (wxPython + wxVTKRenderWindowInteractor + widget)
Paul Melis
paul at science.uva.nl
Wed Mar 7 07:21:00 EST 2007
Hmmm,
The code didn't get through correctly in the post, so I've put a copy at
http://www.pecm.nl/wxapp_with_widget.py
Paul
Paul Melis wrote:
> Hello,
>
> I'm trying to use one of the 3D VTK widgets in a wxPython application.
> I originally stumbled upon the segfault described below while trying
> to use a vtkImagePlaneWidget, but found that vtkBoxWidget and
> vtkSphereWidget also show the same problem. I include here a stripped
> version of my original app for easy demonstration. This is all with a
> recent CVS version of VTK, wxPython 2.6.3 and Python 2.4.3 on Fedora
> Core 4.
>
> The code below derives a custom frame from wx.Frame, places a button
> and a wxVTKRenderWindowInteractor on that frame. The standard
> headsq/quarter VTK dataset is loaded when the button is pressed and a
> volume rendering is set up using the dataset. A wx.App is created that
> creates the frame and then runs the application main loop. This all
> works as expected, the volume is rendered and can be rotated, zoomed,
> etc.
>
> Problems start when adding a vtkImagePlaneWidget to the pipeline, so
> as to show image slices of the data set. The addition of the widget in
> the code below is guarded with an "if False:", but changing to True
> will add the widget and set its interactor to the
> wxVTKRenderWindowInteractor of the frame. The widget is then placed
> with PlaceWidget() and enabled with On(). When the app is run with the
> widget enabled then any mouse interaction after the dataset is loaded
> will cause a segfault. The relevant (top) part of the stack trace is:
>
> #0 0x00000000 in ?? ()
> #1 0x04543d87 in vtkImagePlaneWidget::ProcessEvents () from
> /home/paul/vtk/bin/libvtkWidgets.so.5.1
> #2 0x055989c1 in vtkCallbackCommand::Execute () from
> /home/paul/vtk/bin/libvtkCommon.so.5.1
> #3 0x0561289a in vtkSubjectHelper::InvokeEvent () from
> /home/paul/vtk/bin/libvtkCommon.so.5.1
> #4 0x05612904 in vtkObject::InvokeEvent () from
> /home/paul/vtk/bin/libvtkCommon.so.5.1
> #5 0x023af093 in
> vtkGenericRenderWindowInteractor::LeftButtonPressEvent () from
> /home/paul/vtk/bin/libvtkRendering.so.5.1
> #6 0x03026dd4 in
> PyvtkGenericRenderWindowInteractor_LeftButtonPressEvent () from
> /home/paul/vtk/bin/libvtkRenderingPythonD.so.5.1
> #7 0x003106c3 in PyCFunction_Call () from /usr/lib/libpython2.4.so.1.0
> #8 0x0034931c in PyEval_EvalFrame () from /usr/lib/libpython2.4.so.1.0
> #9 0x0034aa1c in PyEval_EvalCodeEx () from /usr/lib/libpython2.4.so.1.0
> #10 0x002ff0b1 in PyFunction_SetClosure () from
> /usr/lib/libpython2.4.so.1.0
> #11 0x002ea7c6 in PyObject_Call () from /usr/lib/libpython2.4.so.1.0
> #12 0x002f20ee in PyMethod_Fini () from /usr/lib/libpython2.4.so.1.0
> #13 0x002ea7c6 in PyObject_Call () from /usr/lib/libpython2.4.so.1.0
> #14 0x00343b1c in PyEval_CallObjectWithKeywords () from
> /usr/lib/libpython2.4.so.1.0
> #15 0x004be8de in wxPyCallback::EventThunker () from
> /usr/lib/python2.4/site-packages/wx-2.6-gtk2-unicode/wx/_core_.so
> #16 0x009fed3d in wxAppConsole::HandleEvent () from
> /usr/lib/libwx_baseu-2.6.so.0
> #17 0x00a87c7f in wxEvtHandler::ProcessEventIfMatches () from
> /usr/lib/libwx_baseu-2.6.so.0
> #18 0x00a87d40 in wxEvtHandler::SearchDynamicEventTable () from
> /usr/lib/libwx_baseu-2.6.so.0
> #19 0x00a87fe5 in wxEvtHandler::ProcessEvent () from
> /usr/lib/libwx_baseu-2.6.so.0
> #20 0x00f07fda in wxWinModule::wxCreateObject () from
> /usr/lib/libwx_gtk2u_core-2.6.so.0
> [...]
>
> There seems to be a null pointer being used somewhere, but looking at
> vtkImagePlaneWidget::ProcessEvents() the only candidate for that would
> be the parameter "clientdata" as it is the only one used in the
> method. This is so deep within VTK that I don't know what's going on.
> Perhaps I'm setting things up slightly wrong or maybe there's a
> problem with the wxVTKRenderWindowInteractor.
>
> Any help would be greatly appreciated,
> Paul
>
> ===============================
> #!/usr/bin/env python
> import sys
> import wx
>
> import vtk
> from vtk.wx.wxVTKRenderWindowInteractor import
> wxVTKRenderWindowInteractor
>
> from vtk.util.misc import vtkGetDataRoot
> VTK_DATA_ROOT = vtkGetDataRoot()
>
> class MainFrame(wx.Frame):
> def __init__(self, parent, title):
> wx.Frame.__init__(self, parent, -1, title)
> self.button = wx.Button(self, -1, "Load!")
> self.button.SetDefault()
> self.Bind(wx.EVT_BUTTON, self.OnLoad, self.button)
>
> self.vtk_widget = wxVTKRenderWindowInteractor(self, -1,
> size=wx.Size(800,600))
> self.vtk_widget.Enable(1) sizer =
> wx.BoxSizer(wx.VERTICAL) sizer.Add(self.button, 0,
> wx.EXPAND)
> sizer.Add(self.vtk_widget, 1, wx.EXPAND|wx.ALL, 1)
> self.CreateStatusBar()
> self.SetStatusText("")
> self.vtk_renderer = vtk.vtkRenderer()
> self.vtk_renderer.AddObserver("StartEvent", lambda o,e:
> self.OnRenderingStart(o,e))
> self.vtk_renderer.AddObserver("EndEvent", lambda o,e:
> self.OnRenderingEnd(o,e))
> self.vtk_widget.GetRenderWindow().AddRenderer(self.vtk_renderer)
> self.SetSizer(sizer)
> sizer.SetSizeHints(self)
> def OnRenderingStart(self, obj, evt):
> self.SetStatusText("Rendering")
> self.Update()
> wx.Yield() def OnRenderingEnd(self, obj, evt):
> self.SetStatusText("")
> self.Update()
> wx.Yield() def OnLoad(self, evt):
>
> # Load a volume, use the widget to control what's volume
> # rendered. Basically the idea is that the vtkBoxWidget
> provides a box
> # which clips the volume rendering.
> v16 = vtk.vtkVolume16Reader()
> v16.SetDataDimensions(64, 64)
> v16.GetOutput().SetOrigin(0.0, 0.0, 0.0)
> v16.SetDataByteOrderToLittleEndian()
> v16.SetFilePrefix(VTK_DATA_ROOT+ "/Data/headsq/quarter")
> v16.SetImageRange(1, 93)
> v16.SetDataSpacing(3.2, 3.2, 1.5)
> print "scalar range:",
> v16.GetOutput().GetScalarRange()
>
> tfun = vtk.vtkPiecewiseFunction()
> tfun.AddPoint(70.0, 0.0)
> tfun.AddPoint(599.0, 0)
> tfun.AddPoint(600.0, 0)
> tfun.AddPoint(1195.0, 0)
> tfun.AddPoint(1200, .2)
> tfun.AddPoint(1300, .3)
> tfun.AddPoint(2000, .3)
> tfun.AddPoint(4095.0, 1.0)
>
> ctfun = vtk.vtkColorTransferFunction()
> ctfun.AddRGBPoint(0.0, 0.5, 0.0, 0.0)
> ctfun.AddRGBPoint(600.0, 1.0, 0.5, 0.5)
> ctfun.AddRGBPoint(1280.0, 0.9, 0.2, 0.3)
> ctfun.AddRGBPoint(1960.0, 0.81, 0.27, 0.1)
> ctfun.AddRGBPoint(4095.0, 0.5, 0.5, 0.5)
>
> compositeFunction = vtk.vtkVolumeRayCastCompositeFunction()
>
> volumeMapper = vtk.vtkVolumeRayCastMapper()
> volumeMapper.SetInputConnection(v16.GetOutputPort())
> volumeMapper.SetVolumeRayCastFunction(compositeFunction)
>
> volumeProperty = vtk.vtkVolumeProperty()
> volumeProperty.SetColor(ctfun)
> volumeProperty.SetScalarOpacity(tfun)
> volumeProperty.SetInterpolationTypeToLinear()
> volumeProperty.ShadeOn()
>
> newvol = vtk.vtkVolume()
> newvol.SetMapper(volumeMapper)
> newvol.SetProperty(volumeProperty)
> self.vtk_renderer.AddVolume(newvol)
> self.vtk_renderer.SetBackground(0, 0, 0)
>
> # Show an outline (box)
> if False: outline = vtk.vtkOutlineFilter()
> outline.SetInputConnection(v16.GetOutputPort())
> outlineMapper = vtk.vtkPolyDataMapper()
> outlineMapper.SetInputConnection(outline.GetOutputPort())
> outlineActor = vtk.vtkActor()
> outlineActor.SetMapper(outlineMapper)
>
> self.vtk_renderer.AddActor(outlineActor)
> # vtkImagePlaneWidget
> if False:
> ipw = vtk.vtkImagePlaneWidget()
> ipw.SetInput(v16.GetOutput())
> ipw.SetPlaneOrientationToXAxes()
> ipw.SetSliceIndex(1)
> ipw.DisplayTextOn()
> picker = vtk.vtkCellPicker()
> ipw.SetPicker(picker)
>
> ipw.SetInteractor(self.vtk_widget._Iren)
> ipw.PlaceWidget()
> ipw.On()
> # vtkSphereWidget
> if False:
> w = vtk.vtkSphereWidget()
> w.SetInput(v16.GetOutput())
> w.SetInteractor(self.vtk_widget._Iren)
> w.PlaceWidget()
> w.On()
>
> class MyApp(wx.App):
> def OnInit(self):
> frame = MainFrame(None, "VTK")
> self.SetTopWindow(frame)
> frame.Show(True)
>
> return True
>
> app = MyApp(redirect=False)
>
> app.MainLoop()
>
> ==========================
>
>
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