//Adjust the camera axial scale for zoom persistent objects 
      gp_XYZ anAxialScale = theCamera->AxialScale();
      Standard_Real anAxialX = anAxialScale.X();
      Standard_Real anAxialY = anAxialScale.Y();
      Standard_Real anAxialZ = anAxialScale.Z();
      if (anAxialX > 0 && anAxialY > 0 && anAxialZ > 0)
      {
        Graphic3d_TransformUtils::Scale(aWorldView, 1.0 / anAxialX, 1.0 / anAxialY, 1.0 / anAxialZ);
      }

if ((myMode & Graphic3d_TMF_AxialScalePers) != 0)
{
  //...
}

if (myIsZoomPersistentMode)
  {
    if (TransformPersistence().IsNull()
    ||  TransformPersistence()->Mode() != Graphic3d_TMF_ZoomPers
    || !TransformPersistence()->AnchorPoint().IsEqual (myPosition.Location(), 0.0))
    {
      setTransformPersistence (new Graphic3d_TransformPers (Graphic3d_TMF_ZoomPers, myPosition.Location()));
    }
  }

Standard_OutOfRange_Raise_if (theAxialScale.X() <= 0.0 || theAxialScale.Y() <= 0.0 || theAxialScale.Z() <= 0.0, "Graphic3d_Camera::SetAxialScale, bad coefficient");

  Graphic3d_TMF_AxialZoomPers  = Graphic3d_TMF_ZoomPers
                               | Graphic3d_TMF_AxialScalePers //!< Object doesn't resize locally or with axial scale.

//! Graphic3d_TMF_AxialPers and Graphic3d_TMF_AxialZoomPers defines persistence in the axial scale.

Graphic3d_TransformUtils::Scale (aWorldView, 1.0 / theCamera->AxialScale().X(), 1.0 / theCamera->AxialScale().Y(), 1.0 / theCamera->AxialScale().Z());

// Adjust the camera axial scale to preserve trihedron shape.
// Adjust the camera axial scale for axial scale persistent objects.

(Graphic3d_TMF_AxialScalePers & myMode) == 0

      ViewerTest::GetAISContext()->Remove  (aManipulator, Standard_False);
      ViewerTest::GetAISContext()->Display (aManipulator, Standard_False);
      ViewerTest::GetAISContext()->Redisplay (aManipulator, Standard_False);