Example
For example we will create view that contains emitter layer and animates particles.
import QuartzCore
class ConfettiView: UIView {
// main emitter layer
var emitter: CAEmitterLayer!
// array of color to emit
var colors: [UIColor]!
// intensity of appearance
var intensity: Float!
private var active :Bool!
required init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
setup()
}
override init(frame: CGRect) {
super.init(frame: frame)
setup()
}
func setup() {
// initialization
colors = [UIColor.redColor(),
UIColor.greenColor(),
UIColor.blueColor()
]
intensity = 0.2
active = false
}
func startConfetti() {
emitter = CAEmitterLayer()
emitter.emitterPosition = CGPoint(x: frame.size.width / 2.0, y: -20)
emitter.emitterShape = kCAEmitterLayerLine
emitter.emitterSize = CGSize(width: frame.size.width, height: 1)
var cells = [CAEmitterCell]()
for color in colors {
cells.append(confettiWithColor(color))
}
emitter.emitterCells = cells
layer.addSublayer(emitter)
active = true
}
func stopConfetti() {
emitter?.birthRate = 0
active = false
}
func confettiWithColor(color: UIColor) -> CAEmitterCell {
let confetti = CAEmitterCell()
confetti.birthRate = 10.0 * intensity
confetti.lifetime = 180.0 * intensity
confetti.lifetimeRange = 0
confetti.color = color.CGColor
confetti.velocity = CGFloat(350.0 * intensity)
confetti.velocityRange = CGFloat(40.0 * intensity)
confetti.emissionLongitude = CGFloat(M_PI)
confetti.emissionRange = CGFloat(M_PI_4)
confetti.spin = CGFloat(3.5 * intensity)
confetti.spinRange = CGFloat(4.0 * intensity)
// WARNING: A layer can set this property to a CGImageRef to display the image as its contents.
confetti.contents = UIImage(named: "confetti")?.CGImage
return confetti
}
internal func isActive() -> Bool {
return self.active
}
}
You need to add "confetti" image or define rect with confetti.contentsRect
