Using Win2D in a library? (PCL?) about win2d HOT 2 CLOSED

Interesting question! I don't know F# well, but if I am correctly interpreting what I see in Visual Studio, I think this issue is due to the lack of a non-PCL F# library template supporting Windows Store.

PCL (Portable Class Library) is a very restricted subset that can only reference APIs that are universally available on all the enabled target platforms. Because Win2D is a WinRT component implemented using native code, it is not accessible from a PCL.

In C#, there are two options for library projects:

• Store Apps / Universal Apps / Class Library (Portable for Universal Apps) is a PCL, so cannot reference Win2D
• Store Apps / Windows Apps / Class Library (Windows) is a regular (non-PCL) class library that supports Windows Store and can reference Win2D

But when I look at the F# project templates, I see only:

• Library (which is not for Windows Store)
• Portable Library (which is a PCL)

I'm not sure why F# is missing the option of a non-PCL library project that targets Windows Store, but without this I don't think it will be possible to directly access Win2D. At least not currently - we will do some more digging to see if there isn't some way we might be able to support PCL better, but I'm not sure how or even if that may be possible.

You could use the C# "Class Library (Windows)" project type as a proxy except I suspect this will run into the same issue that you won't be able to reference that C# project from an F# PCL.

Unless I'm missing something, it looks like F# support for calling WinRT APIs is currently not very complete, or at least that Visual Studio does not include a full set of templates for this type of project.

from win2d.

Hello again - I spent some more time looking into this and here's what I found out:

1. There is not currently any good way to consume a WinRT component such as Win2D from a .NET portable class library (PCL) like the default F# project type. There's nothing we can change in the Win2D packaging to make that work.

2. This means that to access Win2D from F#, you would need to create a non-PCL F# project targeting the Windows Store platform. Unfortunately there does not seem to be any support for this in F#, although I am extremely newbie in the world of F# so might just not be aware how to do it.

3. One structure that will work is to implement your app logic as an F# PCL, then consume the resulting F# assembly from a C# app project which can use Win2D to draw the data that was calculated by F# code. The project dependencies only work this way around, though: C# Windows Store project using Win2D can call into F# PCL, but it is not possible for an F# PCL to call into a C# Windows Store library project (F# PCL can only call C# library if that C# library is also PCL, in which case the C# PCL library could not use Win2D).

Hope that helps,

from win2d.