SwiftUI view to try out SF Pro with various widths and weights

ContentView.swift

import SwiftUI

struct ContentView: View {
	@State var width: Float = 0
	@State var weight: Float = 0
	
    var body: some View {
        VStack {
			HStack{
				Text("Width")
				Spacer()
				Slider(value: $width, in: -0.4...0.3)
				Spacer()
				Text(String(format: "%.f%%", (width+1)*100))
			}
			HStack{
				Text("Weight")
				Spacer()
				Slider(value: $weight, in: -0.8...0.6)
				Spacer()
				Text(String(format: "%.f%%", (weight+1)*100))
			}
			
			Text("Hello, world!")
				.font(Font(uiFont(width: width, weight: weight)))
        }
        .padding()
    }
	
#if os(macOS)
	typealias XFont = NSFont
#else
	typealias XFont = UIFont
#endif
	
	func uiFont(width: Float, weight: Float) -> XFont! {
		let desc = XFont
			.monospacedDigitSystemFont(ofSize: 40, weight: .regular)
			.fontDescriptor
			.addingAttributes([.traits: [
				kCTFontWidthTrait: width,
				kCTFontWeightTrait: weight
			]])
		return XFont(descriptor: desc, size: 0)
	}
}

#Preview {
    ContentView()
}