[vtkusers] plotting bar chart with vtkBarChartActor and vtkXYPlotActor

[michiel mentink]

Dear All,

I'd like to plot a histogram of an image volume, file type metaImage.

I've managed to plot a histogram using the xyPlotActor, yet I have no way of
verifying if it is alright.
It also produces a segmentation fault.

I can't get the same histogram plotted using the BarChartActor.

Could anybody verify my code of both plots? Sorry, I'm a beginner, and at
this point I'm stuck.

Kind regards,

Michael

#include <vtkImageData.h>
#include <vtkMetaImageReader.h>
#include <vtkImageAccumulate.h>
#include <vtkSmartPointer.h>
#include <vtkBarChartActor.h>
#include "vtkRenderer.h"
#include "vtkRenderWindow.h"
#include "vtkRenderWindowInteractor.h"
#include "vtkPolyDataMapper.h"
#include "vtkActor.h"
#include "vtkContourFilter.h"
#include "vtkImageAccumulate.h"
#include "vtkXYPlotActor.h"
#include "vtkImageThreshold.h"

int main(int argc, char *argv[])
{
// handle the arguments
if(argc != 2)
    {
    vtkstd::cout << "Required arguments: filename.mhd" << vtkstd::endl;
    }

// open a metaimage
vtkMetaImageReader * metaImageReader = vtkMetaImageReader::New();
metaImageReader->SetFileName(argv[1]);

//metaImageReader->Update();
vtkSmartPointer<vtkImageAccumulate> histogram =
vtkSmartPointer<vtkImageAccumulate>::New();

histogram->SetInput(metaImageReader->GetOutput());
// sets number of bins: 10 = N# bins
  histogram->SetComponentExtent(0, 4000, 0, 0, 0, 0);
  histogram->SetComponentOrigin(0, 0, 0);
  histogram->SetComponentSpacing(0.16, 0.16, 3.26); // component spacing:
depends on spacing of input volume
  histogram->UpdateWholeExtent();

    vtkXYPlotActor* plot = vtkXYPlotActor::New();
    plot->ExchangeAxesOff();
    plot->SetLabelFormat("%g");

 //   plot->SetXRange(0, 320);
 //   plot->SetYRange(0, 10000);
    plot->SetXTitle("Iso Surface Level");
    plot->SetYTitle("Frequency");
    plot->AddInput(histogram->GetOutput());
    plot->SetXValuesToValue();

    vtkBarChartActor* plot2 = vtkBarChartActor::New();
    plot2->SetInput(histogram->GetOutput());

  vtkRenderer *aRenderer = vtkRenderer::New();
    vtkRenderWindow *renWin = vtkRenderWindow::New();
    renWin->AddRenderer(aRenderer);
    vtkRenderWindowInteractor *iren =
    vtkRenderWindowInteractor::New();
    iren->SetRenderWindow(renWin);

  aRenderer->AddActor(plot);

  renWin->SetSize(640, 480);

  // Initialize the event loop and then start it.
  iren->Initialize();
  iren->Start();

   vtkRenderer *aRenderer2 = vtkRenderer::New();
    vtkRenderWindow *renWin2 = vtkRenderWindow::New();
    renWin2->AddRenderer(aRenderer2);
    vtkRenderWindowInteractor *iren2 =
    vtkRenderWindowInteractor::New();
    iren2->SetRenderWindow(renWin2);

  aRenderer2->AddActor(plot2);

  renWin2->SetSize(640, 480);

  // Initialize the event loop and then start it.
  iren2->Initialize();
  iren2->Start();

  histogram->Delete();
  plot->Delete();
  plot2->Delete();
  iren->Delete();
  renWin->Delete();
  aRenderer->Delete();

return (0);
}
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