private void SetControlMode()
 {
     if (_controlMode == null)
     {
         _controlMode = new DefaultControlMode(this);
     }
 }
        public void Dispose()
        {
            if (_imageHandler != null)
            {
                _imageHandler.ImageUpdated -= ImageHandlerImageUpdated;
            }

            _imageHandler   = null;
            _shader         = null;
            _controlMode    = null;
            _viewMode       = null;
            _viewParametres = null;
        }