Support using Win2D with WinUI

[jtorjo]

In light of WinUI roadmap, the Windows.UI.Composition will become independent of UWP.

Would this mean we could actually uncouple win2d from UWP? Assuming we could use c++/WinRT from a non-UWP app, could the library be made useable from UWP/WPF alike?

Quote from microsoft/microsoft-ui-xaml#888
We know that using WinUI in desktop apps is the most interesting scenario for lots of Windows app developers. The goal is to enable using Xaml markup + WinRT APIs (via .NET or C++) as the UI for a win32/desktop app (instead of a UWP app), without needing to use Xaml Islands.

[Gavin-Williams]

This will have to happen, because although UWP will continue, UWP.UI will be deprecated and we will be using WinUI.

[jtorjo]

@Gavin-Williams I truly hope so, because UWP is giving me nightmares

[jasonwurzel]

Any news on this? We are in the process of deciding the roadmap for our application and this is a crucial point: Will we be able to use Win2D in a WinUI 3 project? What would be the necessary changes to make in Win2D (I guess only replacing some namespaces would not be sufficient).

[jtorjo]

@jasonwurzel I certainly can't speak on MS's name - I only speak for myself, I've been following WinUI3 talks, and asked a few questions.
Having said that, it may happen, but my take is - don't expect this to happen before mid summer next year.

I'm not putting that much hope into it, because UWP and WPF are sooo different (for one WPF - on top of Directx9, UWP on top of Directx11). I'm not sure they'll redo WPF on Directx11 (even though that would be incredibly cool), so using win2d from WPF might end up being too much work.

Assuming you have a WPF app, and you really really need win2d (such as in my case), you're likely choice is to port it to UWP. In that case, do expect a really bumpy ride.

[jasonwurzel]

Oh, we're already on the bumpy ride :-/ I should have clarified the status quo in my first post: We have a UWP app, to be more precise, we have a WPF Core app that hosts one XamlIsland that hosts our UWP app. Did I mention "bumpy ride" yet? ;-)
Anyway, as WinUI 3 points to the future (in .Net 5 direction) I expect Win2D to be available for sure, the question is just, when (I concur with you on your assesment of summer next year) and what has to be done in Win2D to make it available in WinUI 3 (just out interest, and of course one could help).

[jtorjo]

Oh wow - good luck!
So you basically need to publish your app in the MS store, and then somehow use it from WPF?
Good times...

About using win2d from a WinUI 3 project - i'm really curious how they will reconcile the pathetic StorageFile/Folder API they must be using in UWP, with WPF. We'll have to wait and see :)

[rucoder]

Here is community talk on WinUI 3.0. https://onedrive.live.com/?authkey=%21ADasoGSDRbpnShA&cid=9C95F4380C440E2C&id=9C95F4380C440E2C%2132156&parId=9C95F4380C440E2C%2132155&o=OneUp

At around 19:00 they discuss a question "Can you use Win2D with WinUI 3.0?" and the answer was "Sure, you just need to recompile Win2D against WinUI 3.0" I personally have the same problem: I need to decide which technology to use for our new Windows application and I also need a performance and features of DirectX. This would be the perfect choice: WinUI 3.0 + Win2D

So My question to Win2D team: is there any plan to release a separate NuGet package compiled against WinUI 3.0 ?

[rucoder]

It seems initial version of toolkit for WinUI 3.0 exists now
CommunityToolkit/WindowsCommunityToolkit#3146

[lhak]

I have managed to compile win2d for winui (see https://github.com/lhak/Win2D/tree/winui3). Most of the changes are rather trivial but there are also some hacks:

• The winui header and idl files were manually created from the winui .winmd file and copied to the project. I had to edit them later to remove code that caused compilation to fail (e.g. experimental flags and some double definitions). This generation needs to somehow happen automatically (and correctly) or the files should be supplied directly by the winui team in the winui package. Unfortunately, I do not really have any experience in this field.
• Composition support is disabled because some of the required classes do not seem to be currently present in winui
• Some code in CanvasAnimatedControl is also disabled because the swapchain class lacks a certain method
• CanvasBitmap derives from DependencyObject in the current codebase. I had to remove this because when it derives from the winui version there is a crash in the cswinrt code when a CanvasBitmap object is created.
• I added some code from the cswinrt website to generate projections for c# desktop apps in the bin\cswinrt folder

So far the included SimpleSample app seems to work. I have also successfully tested CanvasControl and CanvasSwapChain in a c# desktop app by adding the projection files to project and copying the win2d dll to the output folder.

[michael-hawker]

@rucoder thanks for linking to the Toolkit. We have preview bits available that work on Preview 1 here. However, they don't support anything that uses Win2D yet as Win2D doesn't yet support WinUI. We've been talking to the Win2D team about this.

@lhak that's a great investigation! 🎉🎉🎉 Thanks for driving the discussion by taking such a detailed look at the problems!