将AbsoluteLayout用于背景图像，但某些元素未正确定位Xamarin表单

using Xamarin.Forms;

AbsoluteLayout absoluteLayout = new AbsoluteLayout();
Content = absoluteLayout;

Image backgroundImage = new Image
{
    Source = "background.jpg",
    Aspect = Aspect.AspectFill
};
AbsoluteLayout.SetLayoutBounds(backgroundImage, new Rectangle(0, 0, 1, 1));
AbsoluteLayout.SetLayoutFlags(backgroundImage, AbsoluteLayoutFlags.All);
absoluteLayout.Children.Add(backgroundImage);

Label titleLabel = new Label
{
    Text = "Welcome to Xamarin.Forms",
    FontSize = 24,
    TextColor = Color.White
};
AbsoluteLayout.SetLayoutBounds(titleLabel, new Rectangle(0.5, 0.5, AbsoluteLayout.AutoSize, AbsoluteLayout.AutoSize));
AbsoluteLayout.SetLayoutFlags(titleLabel, AbsoluteLayoutFlags.PositionProportional);
absoluteLayout.Children.Add(titleLabel);