link slider events (#413)

Co-authored-by: github-actions <github-actions@github.com>
Co-authored-by: DanicaSTFC <138598662+DanicaSTFC@users.noreply.github.com>

CHANGELOG.md

@@ -4,7 +4,7 @@
 
 New functionality:
 - Add method to edit axes label text & tests, hide one label on 2D viewer #389 #408
-- Add slider widget #365 and option to not install it #386
+- Add slider widget #365 and option to not install it #386. Link slider events #413
 
 Bugfixes:
 - Fix failing unit test #394

Wrappers/Python/ccpi/viewer/CILViewer2D.py

@@ -1497,7 +1497,7 @@ def installSliceSliderWidgetPipeline(self):
         cb = SliderCallback(self, sw)
 
         # Add interaction observers
-        # propagate events from the slider to the viewer
+        # to propagate events from the slider to the viewer
         sw.AddObserver(vtk.vtkCommand.InteractionEvent, cb)
 
         # propagate events from the viewer to the slider

Wrappers/Python/ccpi/viewer/viewerLinker.py

@@ -3,6 +3,8 @@
 from ccpi.viewer.CILViewer import CILInteractorStyle as CIL3DInteractorStyle
 from ccpi.viewer.CILViewer2D import CILInteractorStyle as CIL2DInteractorStyle
 
+from ccpi.viewer.widgets.slider import SLIDER_EVENT
+
 
 class Linked3DInteractorStyle(CIL3DInteractorStyle):
     """
@@ -311,6 +313,19 @@ def __call__(self, interactor, event):
                 if (self.sourceVtkViewer.getSliceOrientation() != self.targetVtkViewer.getSliceOrientation()):
                     shouldPassEvent = False
 
+        # Slice from the slider
+        if event == "NoEvent" and self.linkSlice:
+            # Although I invoked a SLIDER_EVENT in widgets/slider.py, I noticed that a
+            # NoEvent is actually emitted/received. Therefore, we will link the slice in case of a
+            # NoEvent and self.linkSlice=True
+            if (not self.linkSlice):
+                shouldPassEvent = False
+            else:
+                # Set current slice
+                sliceno = self.sourceViewer.getActiveSlice()
+                self.targetInteractor.GetInteractorStyle().SetActiveSlice(sliceno)
+                self.targetInteractor.GetInteractorStyle().UpdatePipeline(True)
+
         # KeyPress and orientation
         if (event == "KeyPressEvent" or state == 1026):
             orientation_link_event = self.linkOrientation and (interactor.GetKeyCode() == "x"

Wrappers/Python/ccpi/viewer/widgets/slider.py

@@ -2,6 +2,8 @@
 import logging
 
 logger = logging.getLogger(__name__)
+# Define a new event type
+SLIDER_EVENT = vtk.vtkCommand.UserEvent + 1
 
 
 class SliceSliderRepresentation(vtk.vtkSliderRepresentation2D):
@@ -95,6 +97,7 @@ def __call__(self, caller, ev):
         value = slider_widget.GetRepresentation().GetValue()
         self.viewer.displaySlice(int(value))
         self.update_label(value)
+        self.viewer.getInteractor().InvokeEvent(SLIDER_EVENT)
 
     def update_label(self, value):
         '''Update the text label on the slider. This is called by update_from_viewer