如何在UWP中创建并绘制位图？

using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Media.Imaging;
using Windows.UI;
using Windows.Foundation;
using Windows.UI.Xaml.Shapes;
using Windows.UI.Xaml.Media;

// 创建位图对象
WriteableBitmap bitmap = new WriteableBitmap(width, height);

// 获取位图的像素缓冲区
using (var stream = bitmap.PixelBuffer.AsStream())
{
    // 创建位图的绘制上下文
    CanvasBitmap canvasBitmap = CanvasBitmap.CreateFromBytes(
        CanvasDevice.GetSharedDevice(), stream, width, height, bitmap.PixelWidth, bitmap.PixelHeight, DirectXPixelFormat.B8G8R8A8UIntNormalized);

    // 创建绘制画布
    CanvasRenderTarget renderTarget = new CanvasRenderTarget(
        CanvasDevice.GetSharedDevice(), width, height, 96);

    // 创建绘制上下文
    using (var ds = renderTarget.CreateDrawingSession())
    {
        // 设置绘制属性
        ds.Clear(Colors.White);
        ds.Antialiasing = CanvasAntialiasing.Antialiased;

        // 绘制图形
        ds.DrawLine(10, 10, 100, 100, Colors.Black);
        ds.DrawRectangle(50, 50, 200, 100, Colors.Red);
        ds.DrawText("Hello, UWP!", 100, 200, Colors.Blue);
    }

    // 将绘制结果复制到位图上
    canvasBitmap.CopyPixelsFromBitmap(renderTarget);

    // 更新位图
    bitmap.Invalidate();
}

// 在界面上显示位图
Image image = new Image();
image.Source = bitmap;