Original: http://swiftplayground.com.br/bandeira-do-brasil-com-uibezierpath-e-swift/

FlagView.swift

//
//  FlagView.swift
//  Bandeira Brasil
//
//  Created by Danilo Altheman on 01/07/14.
//  Copyright (c) 2014 Quaddro. All rights reserved.
//

import UIKit

extension UIColor {
    convenience init(hex: UInt32) {
        var r: CGFloat = (CGFloat((hex & 0xFF0000) >> 16) / 255.0)
        var g: CGFloat = (CGFloat((hex & 0x00FF00) >>  8) / 255.0)
        var b: CGFloat = (CGFloat (hex & 0x0000FF)        / 255.0)
        self.init(red: r, green: g, blue: b, alpha: 1.0)
    }
}

class FlagView: UIView {
    override func drawRect(rect: CGRect) {
        // cores
        let verde   = UIColor(hex: 0x00A859)
        let amarelo = UIColor(hex: 0xFFCC29)
        let azul    = UIColor(hex: 0x3E4095)
        
        // dimensões
        let comprimento: CGFloat = 320
        let modulo:      CGFloat = comprimento / 20.0
        let largura:     CGFloat = modulo * 14.0
        
        let meioHorizontal: CGFloat = comprimento / 2.0
        let meioVertical:   CGFloat = largura / 2.0
        let margemLozango:  CGFloat = modulo * 1.7
        
        let raioCirculo:     CGFloat = modulo * 3.5
        let diametroCirculo: CGFloat = raioCirculo * 2.0
        let origemCirculo            = CGPoint(x: comprimento / 2.0 - raioCirculo, y: largura / 2.0 - raioCirculo)
        
        // retangulo
        let retanguloPath = UIBezierPath(rect: CGRectMake(0, 0, comprimento, largura))
        verde.setFill()
        retanguloPath.fill()
        
        // poligono
        var poligonoPath = UIBezierPath()
        poligonoPath.moveToPoint(CGPointMake(meioHorizontal, margemLozango))
        poligonoPath.addLineToPoint(CGPointMake(comprimento - margemLozango, meioVertical))
        poligonoPath.addLineToPoint(CGPointMake(meioHorizontal, largura - margemLozango))
        poligonoPath.addLineToPoint(CGPointMake(margemLozango, meioVertical))
        poligonoPath.closePath()
        amarelo.setFill()
        poligonoPath.fill()
        
        // circulo
        var circuloPath = UIBezierPath(ovalInRect: CGRectMake(origemCirculo.x, origemCirculo.y, diametroCirculo, diametroCirculo))
        azul.setFill()
        circuloPath.fill()
    }
}