How to fill a path with a radial gradient in SwiftUI - swift

Question

I'm trying to fill a path with a radial gradient, but no matter what I try, it always ends up being one solid color (as in the image below). It should transition from red to blue.
How do you fill a path with a radial gradient in SwiftUI? What am I doing wrong?
Thank you!
struct ContentView: View {
var body: some View {
Rectangle()
.foregroundColor(Color.black)
Path { path in
path.addArc(center: CGPoint(x: 200, y: 200), radius: 100, startAngle: .degrees(0), endAngle: .degrees(360), clockwise: true)
}
.fill(RadialGradient(
gradient: Gradient(colors: [.red, .blue]),
center: UnitPoint(x: 200.0, y: 200),
startRadius: 20.0,
endRadius: 100.0
))
.edgesIgnoringSafeArea(.all)
}
}

Answer 1

As it turns out, UnitPoint's x and y are values between 0 and 1. Some simple math solved the problem.
This works:
struct ContentView: View {
private let x: Double = 200.0
private let y: Double = 200.0
private let radius: CGFloat = 100.0
var body: some View {
GeometryReader { geo in
Rectangle()
.foregroundColor(Color.black)
Path { path in
path.addArc(center: CGPoint(x: self.x, y: self.y), radius: self.radius, startAngle: .degrees(0), endAngle: .degrees(360), clockwise: true)
}
.fill(RadialGradient(
gradient: Gradient(colors: [.red, .blue]),
center: UnitPoint(
x: CGFloat(self.x / Double(geo.size.width)),
y: CGFloat(self.y / Double(geo.size.height))
),
startRadius: self.radius * 0.30,
endRadius: self.radius
))
}
}
}