private void EndOrthoTransform(Point endMouseLocation)
        {
            UpdateOrthoTransform(endMouseLocation);

            m_middleDownInitalPos         = Const.ZERO_POINT;
            m_middleDownInitalCameraTrans = OrthoTransform.ZERO;
        }
 private void BeginOrthoTransform(Point beginMouseLocation)
 {
     m_middleDownInitalPos         = beginMouseLocation;
     m_middleDownInitalCameraTrans = m_cameraTransform;
 }