NA-MIC Project Weeks

Back to Projects List

Subject hierarchy combobox selection bug

Key Investigators

• Chi Zhang (Texas A&M University College of Dentistry, USA)
• Csaba Pintér (Ebatinca SL, Spain)

Project Description

Bug description:

1. Sync a parameter node to a qtMRLComboBox node.
2. Add the parameter node to a subjectHierarchy folder. Both the parameter Node and the qtMRMLComboBox node set to ‘None’.

Slicer Discourse thread

Objective

1. Fix the bug

Approach and Plan

Here is a sample script that connect a qtMRMLComboBox node to a parameter node, and creating a subjectHierarchy folder to add the parameter node to it. Both will be set to ‘None’

import slicer, qt

dialog = qt.QDialog(slicer.util.mainWindow())
layout = qt.QVBoxLayout(dialog)

shComboBox = slicer.qMRMLSubjectHierarchyComboBox()
shComboBox.nodeTypes = ["vtkMRMLMarkupsFiducialNode"]
shComboBox.noneEnabled = True
shComboBox.setMRMLScene(slicer.mrmlScene)

layout.addWidget(qt.QLabel("Select a fiducial (SubjectHierarchyComboBox):"))
layout.addWidget(shComboBox)

runButton = qt.QPushButton("Move selected node into folder (triggers reset)")
layout.addWidget(runButton)

shNode = slicer.vtkMRMLSubjectHierarchyNode.GetSubjectHierarchyNode(slicer.mrmlScene)

def printState(tag):
    print(f"\n[{tag}]")
    print("  shComboBox.currentItem():", shComboBox.currentItem())
    print("  shComboBox.currentNode():", repr(shComboBox.currentNode()))  

# Add the parameter node to a folder
def onRun():
    currentItemID = shComboBox.currentItem()
    if currentItemID == 0:
        print("No selection (currentItemID==0)")
        return

    printState("BEFORE MOVE")

    folderItemID = shNode.CreateFolderItem(shNode.GetSceneItemID(), "SHCombo_TestFolder")
    shNode.SetItemParent(currentItemID, folderItemID)

    printState("AFTER MOVE (post SetItemParent)")

runButton.clicked.connect(onRun)

dialog.show()

[AFTER MOVE (post SetItemParent)]
shComboBox.currentItem(): 0
shComboBox.currentNode(): None
parameter.selectedFiducial: None

If qt combobox signal is blocked using qt.QSignalBlocker, then parameter node will not be set to ‘None’

Progress and Next Steps

1. First finding is that the bug is simpler than seemed originally, and the parameter node is not needed, self-contained test script simplified
2. Actual bug confirmed: when an SH item is reparented in the logic that is selected in a view (tree view or combobox), then that selection is cleared. The reason is that when reparenting, the item is first removed then re-inserted under the new parent
3. PR opened about possible solution - behavior turns out to be wrong in a different way
4. Proper reparenting seems to involve wrapping the steps between beginMoveRows and endMoveRows. This will probably be the correct solution if we can me it work (first attempt is not robust, something is missing)

Illustrations

No response

Background and References

No response