Private/Internal SF Symbols for all Apple platforms

PrivateSymbols.swift

// Credits: https://gist.github.com/zats/ffd6b2c72b8753f043ec769c6c6739b5
// This is a port of that to Swift (For the iOS version) and a re-interpretation to make it support macOS too.
// There's a decent amount of limitations for this, like being unable to properly resize these symbols.
import SwiftUI

#if os(macOS)
class PrivateSymbol {
    private let baseImage: NSImage
    init?(privateSystemName name: String) {
        guard let bundle = Bundle(path: "/System/Library/CoreServices/CoreGlyphsPrivate.bundle"),
              let image = bundle.image(forResource: name) else {
            return nil
        }
        self.baseImage = image
    }
    func imageAsset() -> Image? {
        Image(nsImage: self.baseImage)
    }
}
#else
class PrivateSymbol {
    private let baseImage: UIImage
    init?(privateSystemName name: String) {
        guard let bundle = Bundle(path: "/System/Library/CoreServices/CoreGlyphsPrivate.bundle"),
              let bundleClass = NSClassFromString("_UIAssetManager") as AnyObject?,
              let assetManager = bundleClass.perform(NSSelectorFromString("assetManagerForBundle:"), with: bundle)?.takeUnretainedValue(),
              let baseImage = assetManager.perform(NSSelectorFromString("imageNamed:"), with: name)?.takeUnretainedValue() as? UIImage else {
            return nil
        }
        self.baseImage = baseImage.withRenderingMode(.alwaysTemplate)
    }
    func imageAsset() -> Image? {
        return Image(uiImage: self.baseImage)
    }
}
#endif

extension Image {
    init?(privateSystemName: String) {
        guard let privateSymbol = PrivateSymbol(privateSystemName: privateSystemName) else {
            return nil
        }
        // .resizable() can be removed if you don't care about your symbols changing size at all
        self = privateSymbol.imageAsset() ?? Image(systemName: "invalid.private.symbol") // no longer able to return nil
    }
}
// You HAVE TO USE .fit() if you want your symbols to resize without stretching
extension Image {
    func fit() -> some View {
        self.scaledToFit().aspectRatio(contentMode: .fit)
    }
}
// All in less than 54 lines! (rip to the 50 line mark but I wanted resizing.)

UsageExample.swift

import SwiftUI

struct ContentView: View {
    var body: some View {
        Image(privateSystemName: "apple.silicon")
      // Remember, .fit() and .frame() only work properly on macOS for the moment. I'm going to try to fix it on iOS soon.
        .fit()
        .frame(width: 50, height: 50)
    }
}