gistfile1.cs

using Microsoft.Graphics.Canvas;
using Microsoft.Graphics.Canvas.DirectX;
using Microsoft.Graphics.Canvas.Text;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Runtime.InteropServices.WindowsRuntime;
using Windows.ApplicationModel;
using Windows.Foundation;
using Windows.Foundation.Collections;
using Windows.Storage;
using Windows.Storage.Streams;
using Windows.UI;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Controls.Primitives;
using Windows.UI.Xaml.Data;
using Windows.UI.Xaml.Input;
using Windows.UI.Xaml.Media;
using Windows.UI.Xaml.Navigation;

// The Blank Page item template is documented at http://go.microsoft.com/fwlink/?LinkId=234238

namespace TestWin2DImage
{
    /// <summary>
    /// An empty page that can be used on its own or navigated to within a Frame.
    /// </summary>
    public sealed partial class MainPage : Page
    {
        CanvasBitmap offscreenRenderedBitmap;
        public MainPage()
        {
            this.InitializeComponent();

        }

        private async void MakeImage_Click(object sender, RoutedEventArgs e)
        {
            using (var renderTarget = new CanvasRenderTarget(image, 100, 100, 96))
            {
                using (var ds = renderTarget.CreateDrawingSession())
                {
                    ds.Clear(Colors.Aqua);
                    
                    ds.DrawText("Test at " + DateTime.Now.ToString(), 100, 100, Colors.Orange,
                        new CanvasTextFormat()
                        {
                            FontSize = 10,
                            HorizontalAlignment = CanvasHorizontalAlignment.Left,
                            VerticalAlignment = CanvasVerticalAlignment.Bottom
                        });


                    using (var imageBytestream = new InMemoryRandomAccessStream())
                    {
                        await renderTarget.SaveAsync(imageBytestream, CanvasBitmapFileFormat.Png);
                    
                        offscreenRenderedBitmap = await CanvasBitmap.LoadAsync(image, imageBytestream);
                        image.Invalidate();
                    }
                }
            }
        }

        private void image_Draw(Microsoft.Graphics.Canvas.UI.Xaml.CanvasControl sender, Microsoft.Graphics.Canvas.UI.Xaml.CanvasDrawEventArgs args)
        {
            args.DrawingSession.Clear(Colors.Yellow);
            args.DrawingSession.DrawText("Hello", new Microsoft.Graphics.Canvas.Numerics.Vector2() { X = 10, Y = 10 }, Colors.Red);
            
            if (offscreenRenderedBitmap != null)
            {
                // call succeeds but nothing draws.
                args.DrawingSession.DrawImage(offscreenRenderedBitmap);
            }
        }
    }
}