Fireworks effect by emitter.

Fireworks.swift

let emitterLayer = CAEmitterLayer()
        emitterLayer.frame = navigationView.bounds
        emitterLayer.renderMode = .additive
        emitterLayer.emitterMode = .outline
        emitterLayer.emitterShape = .line
        emitterLayer.emitterSize = CGSize(width: 50, height: 0)
        emitterLayer.emitterPosition = CGPoint(x: navigationView.bounds.width / 2, y: navigationView.bounds.height)
        emitterLayer.velocity = 1
        emitterLayer.seed = (arc4random() % 100) + 1
        navigationView.layer.insertSublayer(emitterLayer, at: 0)
        
        let cell = CAEmitterCell()
        cell.contents = UIImage(named: "triangle1")?.cgImage
        cell.birthRate = 1
        cell.emissionRange = 0.11 * CGFloat.pi
        cell.velocity = 100
        cell.velocityRange = 150
        cell.yAcceleration = 75
        cell.lifetime = 2.04
        cell.scale = 0.2
        cell.color = UIColor(red: 0.5, green: 0.5, blue: 0.5, alpha: 1).cgColor
        cell.greenRange = 1
        cell.redRange = 1
        cell.blueRange = 1
        cell.spinRange = CGFloat.pi
        
        let burst = CAEmitterCell()
        burst.birthRate = 1
        burst.velocity = 0
        burst.scale = 2.5
        burst.redSpeed = -1.5
        burst.blueSpeed = 1.5
        burst.greenSpeed = 1
        burst.lifetime = 0.35
        
        let spark = CAEmitterCell()
        spark.birthRate = 400
        spark.velocity = 125
        spark.emissionRange = 2 * CGFloat.pi
        spark.yAcceleration = 75
        spark.lifetime = 3
        spark.contents = UIImage(named: "triangle2")?.cgImage
        spark.scaleSpeed = -0.2
        spark.greenSpeed = -0.1
        spark.redSpeed = 0.4
        spark.blueSpeed = -0.1
        spark.alphaSpeed = -0.25
        spark.spin = 2 * CGFloat.pi
        spark.spinRange = 2 * CGFloat.pi
        
        burst.emitterCells = [spark]
        cell.emitterCells = [burst]
        emitterLayer.emitterCells = [cell]