plot-easing-function

import QuartzCore
import UIKit
import PlaygroundSupport

public class EasingFunctionGraph: UIView  {

    private var x1: CGFloat
    private var y1: CGFloat
    private var x2: CGFloat
    private var y2: CGFloat
    
    public init(x1: CGFloat, y1: CGFloat, x2: CGFloat, y2: CGFloat) {
        self.x1 = x1
        self.x2 = x2
        self.y1 = y1
        self.y2 = y2
        
        super.init(frame: CGRect(x: 0, y: 0, width: 320, height: 320))
        
        backgroundColor = UIColor.white
        
    }
    
    public required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    override public func draw(_ rect: CGRect) {
        let path = UIBezierPath()
        
        UIColor.blue.setStroke()
        path.lineWidth = 3.0
        path.move(to: CGPoint(x: 0, y: 0))
        path.addCurve(to: CGPoint(x: 1 * rect.maxX, y: 1 * rect.maxY), controlPoint1: CGPoint(x: x1 * rect.maxX, y: y1 *               rect.maxY), controlPoint2: CGPoint(x: x2 * rect.maxX, y: y2 * rect.maxY))
        path.stroke()
        
    }
}

let firstLine = EasingFunctionGraph(x1: 0.25, y1: 0.1, x2: 0.25, y2: 1.0)
firstLine.transform = CGAffineTransform(rotationAngle: CGFloat(M_PI_2))

PlaygroundPage.current.liveView = firstLine