# Mouse click over slice

**URL:** https://discourse.slicer.org/t/mouse-click-over-slice/24967
**Category:** Development
**Created:** [August 28, 2022, 9:33pm UTC](https://discourse.slicer.org/t/mouse-click-over-slice/24967 "2022-08-28T21:33:49Z")
**Posts on this page:** 1
**Showing post:** 2

<div class="post-metadata">

### Author: ![lassoan](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/lassoan/32/13_2.png) [@lassoan](https://discourse.slicer.org/u/lassoan)
#### Post date: [August 29, 2022, 2:59am UTC](https://discourse.slicer.org/t/mouse-click-over-slice/24967/2 "2022-08-29T02:59:27Z")

</div>

By default, in markup widgets `RightButtonClickEvent` interaction event is translated to `WidgetEventMenu` widget event, which displays a context menu. You can remove the old mapping and add a new mapping to a custom event using `widget.SetEventTranslation` (see examples in the [script repository](https://slicer.readthedocs.io/en/latest/developer_guide/script_repository.html)).

For example, you can translate the right-click event to `slicer.vtkSlicerMarkupsWidget.WidgetEventCustomAction1` event, which invokes a `slicer.vtkMRMLMarkupsDisplayNode.CustomActionEvent1` on the markup’s display node. To get notified about the right-click event you just need to add an observer to this event.

Example:

```python
def someCustomAction(caller, eventId):
  markupsDisplayNode = caller
  print(f"Custom action activated in {markupsDisplayNode.GetName()}")

views = [
    slicer.app.layoutManager().threeDWidget(0).threeDView(),
    slicer.app.layoutManager().sliceWidget("Red").sliceView(),
    slicer.app.layoutManager().sliceWidget("Yellow").sliceView(),
    slicer.app.layoutManager().sliceWidget("Green").sliceView()
]

observations = [] # store the observations so that later can be removed
markupsDisplayNodes = slicer.util.getNodesByClass("vtkMRMLMarkupsDisplayNode")
for markupsDisplayNode in markupsDisplayNodes:
    # Add observer to custom actions
    observations.append([markupsDisplayNode, markupsDisplayNode.AddObserver(markupsDisplayNode.CustomActionEvent1, someCustomAction)])
    for view in views:
        markupsDisplayableManager = view.displayableManagerByClassName('vtkMRMLMarkupsDisplayableManager')
        # Assign keyboard shortcut to trigger custom actions
        widget = markupsDisplayableManager.GetWidget(markupsDisplayNode)
        # Remove old event translation
        widget.SetEventTranslation(widget.WidgetStateOnWidget, slicer.vtkMRMLInteractionEventData.RightButtonClickEvent, vtk.vtkEvent.NoModifier, vtk.vtkWidgetEvent.NoEvent)
        # Add new event translation
        widget.SetEventTranslation(widget.WidgetStateOnWidget, slicer.vtkMRMLInteractionEventData.RightButtonClickEvent, vtk.vtkEvent.NoModifier, widget.WidgetEventCustomAction1)

## Remove observations when custom actions are not needed anymore by uncommenting these lines:
# for observedNode, observation in observations:
# observedNode.RemoveObserver(observation)

```

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