Question about rendering WPF Canvas containing multiple Images

Hello Devels,

I want to save the Content of a WPF Canvas (which is in a ScrollViewer, so not all Content is visible) to a png. With the following code I get it working.

void SaveUsingEncoder(Canvas myCanvas, string fileName, int dpi)
        {
            PngBitmapEncoder encoder = new PngBitmapEncoder();
            RenderTargetBitmap bitmap = new RenderTargetBitmap(
                (int)myCanvas.ActualWidth*(int)(dpi/96.0),
                (int)myCanvas.ActualHeight*(int)(dpi/96.0),
                dpi,
                dpi,
                PixelFormats.Pbgra32);

            Rect bounds = VisualTreeHelper.GetDescendantBounds(myCanvas);
            Console.WriteLine(bounds.X + "|" + bounds.Y + "  " + bounds.Width + "|" + bounds.Height);
            DrawingVisual dv = new DrawingVisual();
            using (DrawingContext ctx = dv.RenderOpen())
            {
                VisualBrush vb = new VisualBrush(myCanvas);
                ctx.DrawRectangle(vb, null, new Rect(bounds.Location, bounds.Size));
            }
            bitmap.Render(dv);
            BitmapFrame frame = BitmapFrame.Create(bitmap);
            encoder.Frames.Add(frame);
            using (var stream = File.Create(fileName))
            {
                encoder.Save(stream);
            }
        }

But there is the Issue of Quality: I want to put pictures inside of the Canvas Element, but saving the Canvas is more like making a screenshot with a specific resulution. Are there any better ways to do this?

At the end my application should be able to act like a little paint clone, you can drop pictures into the canvas where you can zoom in/out and then save it to png.