在鼠标光标下画一个椭圆。移动坐标时不起作用

需要将绘图点定位在光标下，鼠标的锐边在中心。使用此选项，画布上的点不会被绘制。如果您安装时没有偏移，那么一切正常。

 public void DrawPoint(Point point, Canvas canvas)
    {
        Ellipse el = new Ellipse();
        el.Width = 10;
        el.Height = 10;
        el.SetValue(Canvas.LeftProperty, point.X);
        el.SetValue(Canvas.TopProperty, point.Y);
        el.Fill = Brushes.Red;

        // Добавление графического элемента на холст.
        canvas.Children.Add(el);
    }

    private void Canvas_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)
    {
        Point point = e.GetPosition(Canvas);
        point.Offset(-5.0, -5.0);

        DrawPoint(point, Canvas);
    }

    private void Canvas_MouseMove(object sender, MouseEventArgs e)
    {
        if (Canvas.Children.Count !=0)
        {
            Canvas.Children.RemoveAt(Canvas.Children.Count - 1);
        }
        Point point = e.GetPosition(Canvas);
        point.Offset(-5.0, -5.0);
        DrawPoint(point, Canvas);
    }

<Canvas  
MouseMove="ContentPanel_MouseMove" 
MouseEnter="ContentPanel_MouseEnter" 
MouseLeave="ContentPanel_MouseLeave"  
MouseLeftButtonDown="Canvas_MouseLeftButtonDown" 
x:Name="Canvas" 
Margin="0,10,0,0" 
Panel.ZIndex="998" 
HorizontalAlignment="Left" 
VerticalAlignment="Top"/>