How to use `CLLocationCoordinate2D` and `Color` data types in Swift Data?

Question

I am converting from a [struct] to Swift Data. Two of my elements don't seem to work in Swift Data.

How do I make types Color and CLLocationCoordinate2D conform to PersistentModel and RelationshipCollection?

I am guessing this is either very easy or impossible. I don't know which, and I don't know how. Any help/pointers will be greatly appreciated‼️

Here's my code:

import Foundation
import SwiftData
import CoreLocation
import CoreMotion
import SwiftUI


@Model
final class Item {
   var timestamp: Date
   var daCount: Int
   var gpsTimestamp: Date
   var location: CLLocationCoordinate2D
   var latitude: Double
   var longitude: Double
   var myColor: Color
   
   init(timestamp: Date, daCount: Int, gpsTimestamp: Date, location: CLLocationCoordinate2D, latitude: Double, longitude: Double, myColor: Color) {
      self.timestamp = timestamp
      self.daCount = daCount
      self.gpsTimestamp = gpsTimestamp
      self.location = location
      self.latitude = latitude
      self.longitude = longitude
      self.myColor = myColor
   }
   
}

When I compile I get the following six errors:

No exact matches in call to instance method 'setValue'

• In expansion of macro '_PersistedProperty' here
• Candidate requires that 'Color' conform to 'PersistentModel' (requirement specified as 'Value' : 'PersistentModel')
• Candidate requires that 'Color' conform to 'RelationshipCollection' (requirement specified as 'Value' : 'RelationshipCollection')

No exact matches in call to instance method 'setValue'

• In expansion of macro '_PersistedProperty' here
• Candidate requires that 'CLLocationCoordinate2D' conform to 'PersistentModel' (requirement specified as 'Value' : 'PersistentModel')
• Candidate requires that 'CLLocationCoordinate2D' conform to 'RelationshipCollection' (requirement specified as 'Value' : 'RelationshipCollection')

No exact matches in call to instance method 'getValue'

• In expansion of macro '_PersistedProperty' here
• Candidate requires that 'Color' conform to 'PersistentModel' (requirement specified as 'Value' : 'PersistentModel')
• Candidate requires that 'Color' conform to 'RelationshipCollection' (requirement specified as 'Value' : 'RelationshipCollection')

No exact matches in call to instance method 'getValue'

• In expansion of macro '_PersistedProperty' here
• Candidate requires that 'CLLocationCoordinate2D' conform to 'PersistentModel' (requirement specified as 'Value' : 'PersistentModel')
• Candidate requires that 'CLLocationCoordinate2D' conform to 'RelationshipCollection' (requirement specified as 'Value' : 'RelationshipCollection')

No exact matches in call to instance method 'setValue'

• In expansion of macro '_PersistedProperty' here
• Candidate requires that 'Color' conform to 'PersistentModel' (requirement specified as 'Value' : 'PersistentModel')
• Candidate requires that 'Color' conform to 'RelationshipCollection' (requirement specified as 'Value' : 'RelationshipCollection')

No exact matches in call to instance method 'setValue'

• In expansion of macro '_PersistedProperty' here
• Candidate requires that 'CLLocationCoordinate2D' conform to 'PersistentModel' (requirement specified as 'Value' : 'PersistentModel')
• Candidate requires that 'CLLocationCoordinate2D' conform to 'RelationshipCollection' (requirement specified as 'Value' : 'RelationshipCollection')

Answer 1

One straightforward solution is to create custom types that conform to Codable that holds the underlying values

struct Coordinate2D: Codable {
    let latitude: Double
    let longitude: Double

    init(latitude: Double, longitude: Double) {
        self.latitude = latitude
        self.longitude = longitude
    }
}

struct RGBValues: Codable {
    let red: Double
    let green: Double
    let blue: Double
    let opacity: Double

    init(red: Double, green: Double, blue: Double, opacity: Double = 1.0) {
        self.red = red
        self.green = green
        self.blue = blue
        self.opacity = opacity
    }
}

They can then be used in the model directly as property types

@Model
final class Place {
    var name: String
    var location: Coordinate2D
    var color: RGBValues

    init(name: String, location: Coordinate2D, color: RGBValues) {
        self.name = name
        self.location = location
        self.color = color
    }
}

You can then for convenience add ways to map between your custom types and the built in types

extension Coordinate2D {
    init(_ location: CLLocationCoordinate2D) {
        self.latitude = location.latitude
        self.longitude = location.longitude
    }

    var location: CLLocationCoordinate2D {
        CLLocationCoordinate2D(latitude: latitude, longitude: longitude)
    }
}

extension RGBValues {
    init(_ color: Color) {
        let resolvedColor = color.resolve(in: .init())
        red = Double(resolvedColor.red)
        green = Double(resolvedColor.green)
        blue = Double(resolvedColor.blue)
        opacity = Double(resolvedColor.opacity)
    }
    var color: Color {
        Color(red: red, green: green, blue: blue, opacity: opacity)
    }
}