Animate Particles With Custom Path

AnimateParticlesWithCustomPath.swift

import UIKit

class ViewController: UIViewController {
    let width: CGFloat = 240.0
    let height: CGFloat = 160.0
    override func viewDidLoad() {
        super.viewDidLoad()
        
        let sineView = HingeView(frame: UIScreen.main.bounds)
        sineView.backgroundColor = .yellow
        view.addSubview(sineView)

        view.addGestureRecognizer(UITapGestureRecognizer(target: self, action: #selector(handleTap)))
    }
    
    func handleTap() {
        (0...10).forEach { (_) in
            generateAnimatedViews()
        }
    }
    
    fileprivate func generateAnimatedViews() {
        let image = drand48() > 0.5 ? #imageLiteral(resourceName: "confetti") : #imageLiteral(resourceName: "diamond")
        let imageView = UIImageView(image: image)
        let dimension = 20 + drand48() * 10
        imageView.frame = CGRect(x: 0, y: 0, width: dimension, height: dimension)
        
        //instead of imageView do , emitter particles
        let confettiView = ConfettiView()
        confettiView.intensity = 0.7
        confettiView.type = ConfettiType.image(image)
        confettiView.startConfetti()
        
        let animation = CAKeyframeAnimation(keyPath: "position")
        
        //animation.path = customPath().cgPath
        //animation.path = trainglePathWithCenter(center: CGPoint(x: 150, y: 150), side:  375 / 2).cgPath
        animation.path = hinge(CGRect(x: 0, y: 0, width: 414, height: 896)).reversing().cgPath
        animation.duration = 2 + drand48() * 3
        animation.fillMode = kCAFillModeForwards
        animation.isRemovedOnCompletion = false
        animation.timingFunction = CAMediaTimingFunction(name: kCAMediaTimingFunctionEaseOut)
        
        //imageView.layer.add(animation, forKey: nil)
        //view.addSubview(imageView)
        confettiView.layer.add(animation, forKey: nil)
        view.addSubview(confettiView)
        
        CATransaction.begin()
        CATransaction.setCompletionBlock {
            let transition = CATransition()
            //transition.delegate = self
            transition.type = kCATransitionFade
            transition.duration = 10
            transition.timingFunction = CAMediaTimingFunction(name: kCAMediaTimingFunctionEaseOut)
            transition.setValue(imageView, forKey: "position")
            transition.isRemovedOnCompletion = false

//            imageView.layer.add(transition, forKey: nil)
//            imageView.layer.opacity = 0

            confettiView.layer.add(transition, forKey: nil)
            confettiView.layer.opacity = 0
            //confettiView.stopConfetti()
        }
        CATransaction.commit()
    }
}

class HingeView: UIView{
    override func draw(_ rect: CGRect) {
        let path = hinge(rect)
        UIColor.black.setStroke()
        path.lineWidth = 3
        path.stroke()
    }
}


fileprivate func hinge(_ rect: CGRect) -> UIBezierPath {
    _ = rect.width
    let height = rect.height

    let path = UIBezierPath()
    let origin = CGPoint(x: 150, y: height)
    path.move(to: origin)
    path.addLine(to: CGPoint(x: 150, y: height / 2))
    
    let endPoint = CGPoint(x: 400, y: 200)
    let randomYShift = 200 + drand48() * 300
    
    let cp1 = CGPoint(x: 150, y: 200 + randomYShift)
    let cp2 = CGPoint(x: 150, y: 200 - randomYShift)
    path.addCurve(to: endPoint, controlPoint1: cp1, controlPoint2: cp2)

    return path
}