How to render InkCanvas to an image in UWP Windows

Question

The RenderTargetBitmap class worked with simple Canvas + InkManager (in Windows 8.1) to render ink strokes to an image. UWP introduced InkCanvas and a new Inking API. However, it seems like the RenderTargetBitmap does not work with that. When I try to capture ink strokes with RenderAsync method, no ink strokes get rendered only other objects like Rectangle and so on.

Is it a bug or this new API is not meant to be used this way? If not, then how can I render an image out of InkCanvas?

Thanks!

Answer 1

Please try InkPresenter.StrokeContainer property http://blogs.windows.com/buildingapps/2015/09/08/going-beyond-keyboard-mouse-and-touch-with-natural-input-10-by-10/

Answer 2

Here is how I solved this issue with Win2D. First of all, add Win2D.uwp nuget package to your project. Then use this code:

CanvasDevice device = CanvasDevice.GetSharedDevice();
CanvasRenderTarget renderTarget = new CanvasRenderTarget(device, (int)inkCanvas.ActualWidth, (int)inkCanvas.ActualHeight, 96);

using (var ds = renderTarget.CreateDrawingSession())
{
    ds.Clear(Colors.White);
    ds.DrawInk(inkCanvas.InkPresenter.StrokeContainer.GetStrokes());
}

using (var fileStream = await file.OpenAsync(FileAccessMode.ReadWrite))
    await renderTarget.SaveAsync(fileStream, CanvasBitmapFileFormat.Jpeg, 1f);