[vtkusers] vtkProbeFilter and vtkPlot

[Eric E. Monson]

Hey Marc,

I'm not sure, offhand, what is going on. Just in case it's relevant, what version of VTK are you using, and on what platform? Are you able to run other tests and examples that use the Charts API? (Charts has changed a lot between 5.6 and the development head, and maybe it's not tested well on your system...?)

Before my original reply I tried a combination of a probe filter, data object to table and vtkChart in Python and it worked okay. I can pass that along to you tomorrow, or I can try to do a quick translation into C++ if you need it. That at least might test some specific pieces on your system that work on mine.

Talk to you later,
-Eric


On Jun 20, 2011, at 3:44 PM, Marc Ferland wrote:

> Hi Eric,
> 
> I've set both X and Y axis to '0':
> 
> ...
> line->SetUseIndexForXSeries(true);
> line->SetInput(mPath->toTable->GetOutput(), 0, 0);
> ...
> 
> But now it just crashes... 
> 
> Here's the relevant part of the stack:
> 
> #6  0x00007ffff24c70ce in std::__throw_logic_error(char const*) () from /usr/lib/libstdc++.so.6
> #7  0x00007ffff2eeedab in std::basic_string<char, std::char_traits<char>, std::allocator<char> >::_S_construct<char const*> (__beg=0x0, 
>     __end=0xffffffffffffffff <Address 0xffffffffffffffff out of bounds>, __a=...) at /usr/include/c++/4.4/bits/basic_string.tcc:134
> #8  0x00007ffff2501e32 in std::basic_string<char, std::char_traits<char>, std::allocator<char> >::basic_string(char const*, std::allocator<char> const&) () from /usr/lib/libstdc++.so.6
> #9  0x00007ffff6ce24d2 in vtkStdString::vtkStdString (this=0x7fffffffdd00, s=0x0) at /home/marc/tmp/vtk/VTK/Common/vtkStdString.h:54
> #10 0x00007ffff6d17488 in vtkPlot::SetInput (this=0xd07b00, table=0xcf7370, xColumn=0, yColumn=0)
>     at /home/marc/tmp/vtk/VTK/Charts/vtkPlot.cxx:372
> #11 0x0000000000411883 in AmplitudeView::buildRenderingPath (this=0x7fffffffdf00)
>     at /home/marc/g3/vtk/ut/dojo/vtk/demoview/amplitudeview.cpp:89
> #12 0x000000000041266f in main (argc=3, argv=0x7fffffffe0f8) at /home/marc/g3/vtk/ut/dojo/vtk/demoview/demo.cpp:74
> 
> The string allocator throws a logic error...?!
> 
> What I'm trying to achieve is something similar to this test: http://vtk.org/gitweb?p=VTK.git;a=blob;f=Widgets/Testing/Cxx/TestSplineWidget.cxx
> 
> but by using the chart API which seems to be the new "preferred" way of plotting data.
> 
> Regards,
> 
> Marc
> 
> 
> On Mon, Jun 20, 2011 at 2:36 PM, Eric E. Monson <emonson at cs.duke.edu> wrote:
> Hey Marc,
> 
> I think you need to set the indices of the X and Y columns in your plot's SetInput() call: e.g. line->SetInput(mPath->toTable->GetOutput(), 0, 1);
> 
> It does look like vtkPlot has a plain SetInput(table) method which gets inherited by vtkPlotPoints and Line, but I get the same errors as you do when I try to set the input to the plot as just a table without specifying the indices.
> 
> If you're using the index as X, then it just won't use the column you pass in as X (you can just give it the Y column index twice, if you want).
> 
> Hope this helps,
> -Eric
> 
> · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · ·
> Eric E Monson
> Duke Visualization Technology Group
> 
> 
> On Jun 20, 2011, at 11:09 AM, Marc Ferland wrote:
> 
> > Hi,
> >
> > I'm currently trying to plot the output of a vtkProbeFilter with the new chart API using a vtkDataObjectToTable filter and I'm having difficulties getting a vtkTable that will be accepted by the plotter. I get errors like:
> >
> > ERROR: In /home/marc/tmp/vtk/VTK/Filtering/vtkAlgorithm.cxx, line 460
> > vtkContextMapper2D (0xd0d630): Attempt to get an input array for an index that has not been specified
> >
> > ERROR: In /home/marc/tmp/vtk/VTK/Charts/vtkPlotPoints.cxx, line 600
> > vtkPlotLine (0xcf9ca0): No Y column is set (index 1).
> >
> > ERROR: In /home/marc/tmp/vtk/VTK/Filtering/vtkAlgorithm.cxx, line 460
> > vtkContextMapper2D (0xd0d630): Attempt to get an input array for an index that has not been specified
> > ....
> >
> > The code looks like this:
> > // Convert the polydata to a vtkTable using points data
> > mPath->toTable = vtkDataObjectToTable::New();
> > mPath->toTable->SetInputConnection(mProbeFilter->GetOutputPort());
> > mPath->toTable->SetFieldType(vtkDataObjectToTable::POINT_DATA);
> > mPath->toTable->Update();
> >
> > // Test
> > vtkTable *table = mPath->toTable->GetOutput();
> > qDebug() << table->GetNumberOfColumns(); // returns 2
> > qDebug() << table->GetNumberOfRows();    // returns 6
> > qDebug() << table->GetValue(0, 0).GetTypeAsString(); // returns: "short"
> > qDebug() << table->GetValue(0, 1).GetTypeAsString(); // returns: "char" <-- weird?!
> >
> > mPath->view = vtkContextView::New();
> > mPath->view->GetRenderer()->SetBackground(0.5, 0.5, 0.5);
> >
> > mPath->chartxy = vtkChartXY::New();
> > mPath->view->GetScene()->AddItem(mPath->chartxy);
> > vtkPlot* line = mPath->chartxy->AddPlot(vtkChart::LINE);
> > line->SetUseIndexForXSeries(true);
> > line->SetInput(mPath->toTable->GetOutput());
> > line->SetColor(0.0, 255, 0.0, 255);
> > line->SetWidth(1.0);
> >
> > FYI: The old XYPlot actor was working correctly with the same probe filter input.
> >
> > So my question is: What am I doing wrong here? Also, is there an example somewhere showing how to correctly use a vtkProbeFilter and the new charting API?
> >
> > Regards,
> >
> > Marc
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