ENH: Allow selection of seed points using vtkSeedWidget

In several use cases in 3D Slicer we need to be able to select a seed point, without allowing it to be moved. Added EnableTranslation (true by default) member to vtkHandleWidget to allow locking a handle but still process events (to be able to detect when the user clicks on the handle). Added seed index to StartInteractionEvent invoked in vtkSeedWidget.
Kitware · May 23, 2017 · b684733 · b684733
1 parent 93ec100
commit b684733
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Showing 4 changed files with 29 additions and 1 deletion.
diff --git a/Interaction/Widgets/Testing/Cxx/TestSeedWidget.cxx b/Interaction/Widgets/Testing/Cxx/TestSeedWidget.cxx
@@ -419,6 +419,14 @@ class vtkSeedCallback : public vtkCommand
       std::cout << "Point placed, total of: "
                 << this->SeedRepresentation->GetNumberOfSeeds() << std::endl;
     }
+    if (event == vtkCommand::StartInteractionEvent)
+    {
+      if (calldata)
+      {
+        std::cout << "Start interacting with seed : "
+                  << *(static_cast< int * >(calldata)) << std::endl;
+      }
+    }
     if (event == vtkCommand::InteractionEvent)
     {
       if (calldata)
@@ -480,6 +488,7 @@ int TestSeedWidget(int argc, char *argv[])
     vtkSmartPointer<vtkSeedCallback>::New();
   scbk->SeedRepresentation = rep;
   widget->AddObserver(vtkCommand::PlacePointEvent,scbk);
+  widget->AddObserver(vtkCommand::StartInteractionEvent,scbk);
   widget->AddObserver(vtkCommand::InteractionEvent,scbk);
 
   // Add the actors to the renderer, set the background and size

diff --git a/Interaction/Widgets/vtkHandleWidget.cxx b/Interaction/Widgets/vtkHandleWidget.cxx
@@ -57,6 +57,7 @@ vtkHandleWidget::vtkHandleWidget()
                                           vtkWidgetEvent::Move,
                                           this, vtkHandleWidget::MoveAction);
   this->EnableAxisConstraint = 1;
+  this->EnableTranslation = 1;
   this->AllowHandleResize    = 1;
 }
 
@@ -250,6 +251,11 @@ void vtkHandleWidget::MoveAction(vtkAbstractWidget *w)
     return;
   }
 
+  if (!self->EnableTranslation)
+  {
+    return;
+  }
+
   // Okay, adjust the representation
   double eventPosition[2];
   eventPosition[0] = static_cast<double>(X);

diff --git a/Interaction/Widgets/vtkHandleWidget.h b/Interaction/Widgets/vtkHandleWidget.h
@@ -117,6 +117,15 @@ class VTKINTERACTIONWIDGETS_EXPORT vtkHandleWidget : public vtkAbstractWidget
   vtkBooleanMacro( EnableAxisConstraint, int );
   //@}
 
+  //@{
+  /**
+   * Enable moving of handles. By default, the handle can be moved.
+   */
+  vtkSetMacro(EnableTranslation, int);
+  vtkGetMacro(EnableTranslation, int);
+  vtkBooleanMacro(EnableTranslation, int);
+  //@}
+
   //@{
   /**
    * Allow resizing of handles ? By default the right mouse button scales
@@ -154,6 +163,7 @@ class VTKINTERACTIONWIDGETS_EXPORT vtkHandleWidget : public vtkAbstractWidget
 
   int WidgetState;
   int EnableAxisConstraint;
+  int EnableTranslation;
 
   // Allow resizing of handles.
   int AllowHandleResize;

diff --git a/Interaction/Widgets/vtkSeedWidget.cxx b/Interaction/Widgets/vtkSeedWidget.cxx
@@ -168,7 +168,10 @@ void vtkSeedWidget::AddPointAction(vtkAbstractWidget *w)
     // Invoke an event on ourself for the handles
     self->InvokeEvent(vtkCommand::LeftButtonPressEvent,NULL);
     self->Superclass::StartInteraction();
-    self->InvokeEvent(vtkCommand::StartInteractionEvent,NULL);
+    vtkSeedRepresentation *rep = static_cast<
+      vtkSeedRepresentation * >(self->WidgetRep);
+    int seedIdx = rep->GetActiveHandle();
+    self->InvokeEvent(vtkCommand::StartInteractionEvent, &seedIdx);
 
     self->EventCallbackCommand->SetAbortFlag(1);
     self->Render();