diff --git a/src/Gui/SoTouchEvents.cpp b/src/Gui/SoTouchEvents.cpp
index 4a34583d35..1cc73540f0 100644
--- a/src/Gui/SoTouchEvents.cpp
+++ b/src/Gui/SoTouchEvents.cpp
@@ -108,8 +108,7 @@ SbBool SoGesturePinchEvent::isSoGesturePinchEvent(const SoEvent *ev) const
  */
 double SoGesturePinchEvent::unbranchAngle(double ang)
 {
-    const double Pi = 3.14159265358979323846;
-    return ang - 2.0*Pi*floor((ang+Pi)/(2.0*Pi));
+    return ang - 2.0 * M_PI * floor((ang + M_PI) / (2.0 * M_PI));
 }