Setting a Scale/ruler while Zooming or moving the vtkresliceimageviewer data

christeen · November 6, 2024, 12:55pm

I am currently working on introducing a scale or ruler feature in VTK within a vtkResliceImageViewer. My goal is for the scale to dynamically update as I zoom in or move the data in the viewer, reflecting the current position and zoom level accurately. I am a beginner with VTK, using C++ as my programming language and VTK version 8.2. Could you please suggest how to achieve this functionality?

I am attaching a GIF to demonstrate my requirement for better clarity. Any guidance on implementing this would be greatly appreciated.

ezgif-6-d6c0e826d2

I tried vtkLegendScaleActor but it’s doesn’t satisfied my whole requirement. I’m stuck in this, I would appreciate any step-by-step guidance on implementing this feature. As a beginner in VTK, detailed instructions would be incredibly helpful and encouraging.

lassoan · November 6, 2024, 11:35pm

As most the other essential medical image computing features, this is already implemented in 3D Slicer using VTK (it works in both 2D and 3D views):

github.com

Slicer/Slicer/blob/fefe4a3401b557f0aec9628c4be2f92fcc4e23eb/Libs/MRML/DisplayableManager/vtkMRMLRulerDisplayableManager.cxx#L267-L402


      
          int viewWidthPixel = 0;
          int viewHeightPixel = 0;
          double scalingFactorPixelPerMm = 0;
          
          vtkMRMLSliceNode* sliceNode = vtkMRMLSliceNode::SafeDownCast(viewNode);
          vtkMRMLViewNode* threeDViewNode = vtkMRMLViewNode::SafeDownCast(viewNode);
          if (sliceNode)
          {
            viewWidthPixel = sliceNode->GetDimensions()[0];
            viewHeightPixel = sliceNode->GetDimensions()[1];
          
            vtkNew<vtkMatrix4x4> rasToXY;
            vtkMatrix4x4::Invert(sliceNode->GetXYToRAS(), rasToXY.GetPointer());
          
            scalingFactorPixelPerMm = sqrt(
              rasToXY->GetElement(0,0)*rasToXY->GetElement(0,0) +
              rasToXY->GetElement(0,1)*rasToXY->GetElement(0,1) +
              rasToXY->GetElement(0,2)*rasToXY->GetElement(0,2));
          
          }

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As always, you can copy the code to your application - there are no restrictions on how you use Slicer or its source code. However, probably this is not the only feature that you’ll need. Your users will require measurements, panoramic image construction, curved planar reformat view, straightened 3D view, AI segmentation of bone, tooth and nerve, etc. and 3D Slicer and its extensions provide help for all these. You can copy all these features to your application, too, but testing and maintaining these features, refactoring your application a few times to accommodate them all, etc. means a lot of work. You can save a time and money and focus on just developing new features that matter by building your application on 3D Slicer as a platform. You can customize the application at many levels to do only what you need, exactly the way you need it. There are now several FDA-approved applications that are built on the 3D Slicer platform.

christeen · November 12, 2024, 7:53am

Is there any class related to VTK, to setup annotate the render window with scale information with respective to XY,YZ and XZ orientation.[For zoom and pan operations - For different render windows]