caemitter.swift

//: A UIKit based Playground for presenting user interface
  
import UIKit
import PlaygroundSupport

final class LayerView: UIView {
    
    override init(frame: CGRect) {
        super.init(frame: frame)
        
        configureLayers()
    }
    
    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
        
        configureLayers()
    }
    
    private func configureLayers() {
        let emitterLayer = CAEmitterLayer()
        
        emitterLayer.emitterPosition = CGPoint(x: 100, y: 100)
        
        let cell = CAEmitterCell()
        cell.birthRate = 10
        cell.lifetime = 100
        cell.velocity = 500
        cell.scale = 0.1
        cell.spin = 1
        
        cell.emissionRange = CGFloat.pi * 2.0
        cell.contents = UIImage(named: "bytes.png")!.cgImage
        
        emitterLayer.emitterCells = [cell]
        
        layer.addSublayer(emitterLayer)
    }
    
}

class MyViewController : UIViewController {
    override func loadView() {
        let view = UIView()
        view.backgroundColor = .white

        let label = UILabel()
        label.frame = CGRect(x: 0, y: 200, width: 320, height: 20)
        label.textAlignment = .center
        label.text = "Animate with CAEmitterLayer!"
        label.textColor = .black
        
        view.addSubview(label)
        
        let layerView = LayerView(frame: CGRect(x: 100, y: 100, width: 100, height: 100))
        view.addSubview(layerView)
        
        self.view = view
    }
}
// Present the view controller in the Live View window
PlaygroundPage.current.liveView = MyViewController()