Means to present more than one deck / have more than one presentation in an app

[appfrosch]

I am currently building an app to create a script for a curriculum to teach a class. I want to include slides in the script in a way so that I can export the script itself including the slides, but also present the slides. The slides can be constructed by parsing the user's input into a Deck.

For presenting the slides, I found this repo and gave it a shot. It's a great package that serves the purpose of creating just one presentation in a DSL manner to present very well. It's also very inspiring, so thanks for sharing it in the first place!

I found out that for my specific use case, the structure of the package should be different though. Presenting a specific deck does not seem possible as it is right now.

I went down the rabbit hole of looking into the Scene API and found out that there is a way to present a specific scene by handing it a specific deck a the callsite.

Consider the following code:

@main
struct DemoApp: App {
    var body: some Scene {
        WindowGroup {
            ContentView()
        }
        #if canImport(AppKit)
        PresenterScene()
        PresenterNotes()
        #endif
    }
}

#if canImport(AppKit)
struct PresenterScene: Scene {
    var body: some Scene {
        WindowGroup("Presentation", for: Deck.self) { $deck in
            if let deck {
                PresentationContentView(deck: deck)
            } else {
                Text("There was an error opening the presentation …")
            }
        }
    }
}
#endif

Opening such a scene at the callsite looks like this:

@Environment(\.openWindow) var openWindow
…
openWindow(value: $deck)

That would enable us to inject a deck when opening the presenter scene window.

The only problem with this is: Deck needs to be Hashable & Codable for that to work. Problem with that is that there are SwitUI types in use that simply are not Codable (I found a workaround to make Color codable, but I failed to find anything useful for Font...)–I most likely have not found all of them yet...

That is, if we were to inject a Deck. One workaround could be to have a store of decks that we can refer to and just inject the UUID of the deck (which would require Deck to conform to Cadable). It would be the PresentationContentView's job to then fetch the deck from the store.

If I can find the time, I will look into this–but perhaps this serves as an inspiration for someone else...
I looked a bit further into this and I think there is a fighting chance to be able have more than one Deck in a project.

Consider the following code:

@main
struct DemoApp: App {
    var body: some Scene {
        WindowGroup {
            ContentView()
        }
        #if canImport(AppKit)
        PresenterScene()
        PresenterNotes()
        #endif
    }
}

#if canImport(AppKit)
struct PresenterScene: Scene {
    var body: some Scene {
        WindowGroup("Presentation", for: Deck.self) { $deck in
            if let document {
                PresentationContentView(document: document)
            } else {
                Text("There was an error opening the presentation …")
            }
        }
    }
}
#endif

Opening such a scene at the callsite looks like this:

@Environment(\.openWindow) var openWindow
…
openWindow(value: $deck)

That would enable us to inject a deck when opening the presenter scene window.
https://developer.apple.com/documentation/swiftui/windowgroup

The only problem with this is: Deck needs to be Hashable & Codable for that to work. Problem with that is that there are SwitUI types in use that simply are not Codable (I found a workaround to make Color codable, but I failed to find anything useful for Font...)–I most likely have not found all of the problematic types yet...

That is, if we were to inject a Deck. One workaround could be to have a store of decks that we can refer to and just inject the UUID of the deck in openWindow. It would be the PresentationContentView's job (in this case) to then fetch the deck from the store.

If I can find the time, I will look into this–but perhaps this serves as an inspiration for someone else...

[appfrosch]

I did a simple implementation of how I could see using the package (almost) as is to present different decks in a fork.

Take a look at Examples/AppfroschDemo if you need some inspiration.