[vtkusers] Strange behavior with vtkCubeAxesActor

[Elvis Stansvik]

Actually, with perspective projection it seems quite okay. See attached
screenshot.

So is this a limitation with vtkCubeAxesActor? It doesn't like parallel
projection?

Elvis

2016-07-04 21:13 GMT+02:00 Elvis Stansvik <elvis.stansvik at orexplore.com>:

> While doing some experimenting, I encountered a strange behavior with
> vtkCubeAxesActor.
>
> The setup I had was this:
>
>
> SampleWidget::SampleWidget(QWidget *parent, Qt::WindowFlags flags)
>     : VTKWidget(parent, flags)
> {
>     auto renderer = vtkSmartPointer<vtkRenderer>::New();
>     renderer->SetBackground(1.0, 1.0, 1.0);
>
>     auto reader = vtkSmartPointer<HDF5ImageReader>::New();
>     reader->setFileName("/home/estan/testvolume.hdf5");
>     reader->setDataSetName("reconstruction");
>
>     auto volumeMapper = vtkSmartPointer<vtkGPUVolumeRayCastMapper>::New();
>     volumeMapper->SetInputConnection(reader->GetOutputPort());
>
>     auto volumeProperty = vtkSmartPointer<vtkVolumeProperty>::New();
>     volumeProperty->SetInterpolationTypeToLinear();
>     volumeProperty->ShadeOff();
>
>     auto opacity = vtkSmartPointer<vtkPiecewiseFunction>::New();
>     opacity->AddPoint(0.0,1.0);
>     opacity->AddPoint(1.0,1.0);
>     volumeProperty->SetScalarOpacity(opacity);
>
>     auto color = vtkSmartPointer<vtkColorTransferFunction>::New();
>     color->AddRGBPoint(0.0,1.0,1.0,1.0);
>     color->AddRGBPoint(1.0,0.0,0.0,0.0);
>     volumeProperty->SetColor(color);
>
>     auto volume = vtkSmartPointer<vtkVolume>::New();
>     volume->SetMapper(volumeMapper);
>     volume->SetProperty(volumeProperty);
>     renderer->AddVolume(volume);
>
>     auto camera = renderer->GetActiveCamera();
>     camera->SetParallelProjection(true);
>
>     auto cubeAxesActor = vtkSmartPointer<vtkCubeAxesActor>::New();
>     cubeAxesActor->SetFlyModeToOuterEdges();
>     cubeAxesActor->SetBounds(volume->GetBounds());
>     cubeAxesActor->SetCamera(renderer->GetActiveCamera());
>     cubeAxesActor->GetTitleTextProperty(0)->SetColor(1.0, 0.0, 0.0);
>     cubeAxesActor->GetLabelTextProperty(0)->SetColor(1.0, 0.0, 0.0);
>     cubeAxesActor->GetTitleTextProperty(1)->SetColor(0.0, 1.0, 0.0);
>     cubeAxesActor->GetLabelTextProperty(1)->SetColor(0.0, 1.0, 0.0);
>     cubeAxesActor->GetTitleTextProperty(2)->SetColor(0.0, 0.0, 1.0);
>     cubeAxesActor->GetLabelTextProperty(2)->SetColor(0.0, 0.0, 1.0);
>
>     renderer->AddActor(cubeAxesActor);
>
>     renderer->ResetCamera();
>
>     GetRenderWindow()->AddRenderer(renderer);
> }
>
> And I got the attached result. Notice how the axis labels don't quite line
> up with the bounding box edge of my volume, and how numbers further away
> are much larger (!) than numbers closer to the camera.
>
> If I don't turn on parallell projection on the camera, the effect is less
> noticable, but still there: The numbers are all the same size, but the
> labels still don't line up with the bounding box edges properly.
>
> Anyone have an idea what's the problem could be?
>
> Thanks in advance,
> Elvis
>
>
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