Flip the ResliceImageViewer

Support
1

I based my code on the FourPaneViewer. In my coronal viewer (vtkResliceImageViewer), the image is displayed, but it appears flipped like a mirror image. I’m trying to correct it to display in the normal orientation.

I attempted to adjust the camera by rotating it with Yaw and Pitch, but this caused the coronal image viewer to become blank. I also tried using SetViewUp(0, -1, 0) to fix the flipped image, but that didn’t work either. Then, I experimented with vtkImageFlip, but it also didn’t resolve the issue. When I used it, the unflipped image was still displayed. I even tried using vtkImageMandelbrotSource and applying the vtkImageFlip operation, but the expected result wasn’t achieved.

2

The FourPaneViewer uses vtkInteractorStyleImage, which is a “camera” interactor style, which means that orienting the camera is the responsibility of the interactor style. When using this, it’s best not to call SetViewUp(), Roll(), Yaw(), etc. on the camera yourself.

Instead, use interactorStyle->SetXViewUpVector(ux, uy, uz) and interactorStyle->SetXViewRightVector(vx, vy, vz) to adjust the coronal slice orientation. You can choose whatever you want for (ux,uy,uz) and (vx,vy,vz) as long as they are orthonormal.

3

It isn’t working at the moment. I’ve tried many times using your suggestion, but the image remains unflipped.

Here’s the code (I’m not very familiar with VTK, so if there’s a mistake, please correct me):

double upVector[3] = { 0.0, 0.0, 1.0 };    // Coronal up vector (z-axis)
double rightVector[3] = { 1.0, 0.0, 0.0 }; // Coronal right vector (x-axis)

m_InteractorStyleCoronal->SetXViewUpVector(upVector[0], upVector[1], upVector[2]);
m_InteractorStyleCoronal->SetXViewRightVector(rightVector[0], rightVector[1], rightVector[2]);
4

Oops, I made a mistake in my suggestion: for coronal, it would be “SetY…” instead of “SetX…”.

But I took a closer look at the vtkResliceImageViewer.cxx code, and it hard-codes the view orientations in its UpdateOrientation() method, so you won’t be able to customize the orientations via the interactor style as I had suggested.

Your best option might be to write your own custom viewer class, based on your app’s requirements.