BreatheApp11.swift

private struct RingHead: Shape {
    var endAngle: Angle
    let ringWidth: CGFloat
    
    var animatableData: Double {
        get {return endAngle.radians}
        set {endAngle = Angle(radians: newValue)}
    }
    
    func path(in rect: CGRect) -> Path {
        var path = Path()
        let radius = (min(rect.width, rect.height) - ringWidth)/2
        let center = CGPoint(x: rect.midX - ringWidth/2, y: rect.midY - ringWidth/2)
        let point = getRotationPoint(angle: endAngle.radians, radius: radius, center: center)
        let frame = CGRect(x: point.x, y: point.y, width: ringWidth, height: ringWidth)
        path.addRoundedRect(in: frame, cornerSize: frame.size)
        return path
    }
    
    func getRotationPoint(angle: Double, radius: CGFloat, center: CGPoint) -> CGPoint {
        return CGPoint(x: center.x + CGFloat(cos(angle)) * radius,
                       y: center.y + CGFloat(sin(angle)) * radius)
    }
}