这个图像平移算法有什么问题?

响应 this question 关于在wpf中缩放和平移,我建议使用scaleTransform并在mousemove事件中更新renderTransform源。这是可行的,但我不高兴的事实是,平移运动不完全匹配鼠标。我知道这个算法有什么问题,但是正确的实现仍然让我难以理解。

private void image_MouseMove(object sender, MouseEventArgs e)
{
    if (image.IsMouseCaptured)
    {
        Vector v = start - e.GetPosition(image);
        // this calculates the deltas relative to the original size of the image
        // but does not take into account the transformed size, but transforming the
        // size like image.ActualWidth * scaleTransform.ScaleX does not help
        double deltax = v.X / image.ActualWidth;
        double deltay = v.Y / image.ActualHeight;

        image.RenderTransformOrigin = new Point(orgin.X + deltax, orgin.Y + deltay);
    }
}

我对如何使这种方法起作用有什么想法吗?