如何使用C# WPF在图像上显示字母

<Window x:Class="WpfApp.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="450" Width="800">
    <Grid>
        <Image Source="path_to_your_image.jpg" Stretch="UniformToFill"/>
        <TextBlock Text="A" FontSize="50" HorizontalAlignment="Center" VerticalAlignment="Center" Background="Transparent"/>
    </Grid>
</Window>

using Microsoft.Win32;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Media;
using System.Windows.Media.Imaging;

namespace WpfApp
{
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
            LoadImageWithText();
        }

        private void LoadImageWithText()
        {
            // 加载图像
            BitmapImage bitmapImage = new BitmapImage(new Uri("pack://application:,,,/path_to_your_image.jpg"));
            Image imageControl = new Image { Source = bitmapImage };

            // 创建WriteableBitmap以便在其上绘制
            WriteableBitmap writeableBitmap = new WriteableBitmap((int)bitmapImage.Width, (int)bitmapImage.Height);
            writeableBitmap.Lock();
            bitmapImage.CopyPixels(writeableBitmap.BackBuffer, bitmapImage.PixelWidth * bitmapImage.Format.BitsPerPixel / 8, 0);
            writeableBitmap.AddDirtyRect(new Int32Rect(0, 0, bitmapImage.PixelWidth, bitmapImage.PixelHeight));
            writeableBitmap.Unlock();

            // 在图像上绘制文本
            DrawingVisual drawingVisual = new DrawingVisual();
            using (DrawingContext drawingContext = drawingVisual.RenderOpen())
            {
                drawingContext.DrawImage(writeableBitmap, new Rect(0, 0, bitmapImage.PixelWidth, bitmapImage.PixelHeight));
                drawingContext.DrawText(new FormattedText("A", System.Globalization.CultureInfo.CurrentCulture, FlowDirection.LeftToRight, new Typeface("Arial"), 50, Brushes.White), new Point((bitmapImage.PixelWidth - 50) / 2, (bitmapImage.PixelHeight - 50) / 2));
            }

            // 将绘制好的图像设置到Image控件
            RenderTargetBitmap renderTargetBitmap = new RenderTargetBitmap((int)bitmapImage.Width, (int)bitmapImage.Height, 96, 96, PixelFormats.Pbgra32);
            renderTargetBitmap.Render(drawingVisual);
            imageControl.Source = renderTargetBitmap;
        }
    }
}