Interpolate Between Colors for UIScrollView

func interpolateColors(progress: CGFloat, light: Bool = false) -> UIColor { let progressInt: Int = Int(floor(progress)) var currentColor: UIColor = UIColor() //set up arrays for rgb color channels let r: [CGFloat] = [0.95, 0.0, 0.81, 0.96, 0.53, 0.95, 0.95] let g: [CGFloat] = [0.38, 0.69, 0.86, 0.74, 0.62, 0.38, 0.38] let b: [CGFloat] = [0.35, 0.61, 0.38, 0.41, 0.93, 0.35, 0.35] var alpha: CGFloat = 1.0 if light { alpha = 0.4 } //if progress < 0 then array index out of range //in this case, return main color (in this case 0.95, 0.38, 0.35) if progress >= 0 { currentColor = UIColor(red: r[progressInt] - (progress-CGFloat(progressInt))*(r[progressInt]-r[progressInt+1]), green: g[progressInt] - (progress-CGFloat(progressInt))*(g[progressInt]-g[progressInt+1]), blue: b[progressInt] - (progress-CGFloat(progressInt))*(b[progressInt]-b[progressInt+1]), alpha: alpha) } else { currentColor = UIColor(red: 0.95, green: 0.38, blue: 0.35, alpha: alpha) } return currentColor }