diff --git a/src/src/Rendering/Measure/LineAnnotationActor.cpp b/src/src/Rendering/Measure/LineAnnotationActor.cpp
index b90bce1..559a5b1 100644
--- a/src/src/Rendering/Measure/LineAnnotationActor.cpp
+++ b/src/src/Rendering/Measure/LineAnnotationActor.cpp
@@ -91,9 +91,8 @@ void LineAnnotationActor::onMeasureMouseMove(vtkRenderWindowInteractor *iren) {
     int y = iren->GetEventPosition()[1];
     vtkRenderer *renderer = iren->FindPokedRenderer(x, y);
     if (!renderer) return;
-    renderer->SetDisplayPoint(x, y, 0.0);
-    renderer->DisplayToWorld();
-    double *p = renderer->GetWorldPoint();
+    double p[3]={0};
+    MapScreenPointToWorld(x,y,renderer,p);
     controlP2->SetWorldPosition(p);
     this->SetWorldPosition2(p);
     iren->Render();
@@ -104,9 +103,8 @@ bool LineAnnotationActor::onMeasureLeftButtonDown(vtkRenderWindowInteractor *ire
     int y = iren->GetEventPosition()[1];
     vtkRenderer *renderer = iren->FindPokedRenderer(x, y);
     if (!renderer) return false;
-    renderer->SetDisplayPoint(x, y, 0.0);
-    renderer->DisplayToWorld();
-    double *p = renderer->GetWorldPoint();
+    double p[3]={0};
+    MapScreenPointToWorld(x,y,renderer,p);
     controlP1->SetWorldPosition(p);
     controlP1->Highlight(0);
     controlP2->SetWorldPosition(p);