//Modify.Choijh.2021.05.27.Insert code Image fit used Mouse Right btn.Start...
        private void Border_PreviewMouseRightButtonDown(object sender, MouseEventArgs e)
        {
            var pos = e.GetPosition(sender as IInputElement);

            _initPos  = pos;
            _offset   = new Point(_viewModel.ZoomService.TranslateX, _viewModel.ZoomService.TranslateY);
            _dragMode = EDragMode.Panning;
        }
        private void Border_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)
        {
            var pos = e.GetPosition(sender as IInputElement);

            _dragMode = EDragMode.Calc;
            if (_viewModel.ZoomService.Scale == 0)
            {
                return;
            }


            _viewModel.StartPt = new Point(
                (pos.X - _viewModel.ZoomService.TranslateX) / _viewModel.ZoomService.Scale,
                (pos.Y - _viewModel.ZoomService.TranslateY) / _viewModel.ZoomService.Scale);
            _viewModel.EndPt      = _viewModel.StartPt;
            _viewModel.IsCalcMode = true;
        }
 private void Border_MouseLeave(object sender, MouseEventArgs e)
 {
     _dragMode             = EDragMode.None;
     _viewModel.IsCalcMode = false;
 }
 private void Border_PreviewMouseUp(object sender, MouseButtonEventArgs e)
 {
     _dragMode             = EDragMode.None;
     _viewModel.IsCalcMode = false;
 }