perf: improve sync slice position function performance

src/src/Interaction/ActorDraggableInteractorStyle.cpp

@@ -501,7 +501,6 @@ void ActorDraggableInteractorStyle::AdjustSyncCrossPoint(double* aPoint)
         }
         else{
             CrossCursorAnnotationActor::SafeDownCast(dragProp)->Transform(aPoint[0] , aPoint[1] );
-            this->Interactor->Render();
         }
     }
 }

src/src/Rendering/Viewer/DICOMImageViewer.cxx

@@ -663,8 +663,7 @@ void DICOMImageViewer::SyncSlicePointSameDirection(double *point) {
         Renderer->GetActiveCamera()->SetFocalPoint(f);
         this->UnActiveReferenceLine();
         this->InteractorStyle->AdjustSyncCrossPoint(displayPoint);
-        this->Render();
-        UpdateTopLeftCornerInfo();
+        UpdateTopLeftCornerInfo();// include render()
         Slice = ImageMapper->GetSliceNumber();
     }
 }