I am new to ITK/VTK programming.
I have written a very simple program using ITK,VTK and Qt, inspired from VTK examples (mainly Examples/GUI/Qt/FourPaneViewer). It simply allows to visualize a 3D image, loaded via ITK.
I would like to be able to load the image via an “open file” menu entry for example and thus build/show the VTK/Qt machinery without having an image yet.
But if I do not load an image at construction, I get the errors:
ERROR: In /home/mansenca/tools/VTK-8.2.0/Common/ExecutionModel/vtkDemandDrivenPipeline.cxx, line 709
vtkCompositeDataPipeline (0x55f5b43cfc50): Input port 0 of algorithm vtkImageMapToWindowLevelColors(0x55f5b4361d40) has 0 connections but is not optional.
I have a repository that reproduces my problem here:
If I execute this program without an image as parameter, I get these errors.
If I pass a valid 3D image as parameter, I don’t get these errors.
What’s wrong with my code ?
I have found several (very old) threads on the old mailing list with the same problems, but they do not give the solution.