Change tint of selected range? about multislider HOT 3 CLOSED

let selectedAreaColor = UIColor.blue.cgColor
    let nonSelectedAreaColor = UIColor.lightGray.cgColor
    @objc func updateValues(_ slider: MultiSlider){
        slider.tintColor = .clear
        slider.trackView.layer.sublayers?.forEach({ (subLayer) in
            if subLayer is CAGradientLayer{
                subLayer.removeFromSuperlayer()
            }
        })
        let layer: CAGradientLayer = CAGradientLayer()
        layer.frame.size = CGSize(width: slider.frame.width , height: slider.trackView.frame.height)
        layer.startPoint = CGPoint.zero
        layer.endPoint = CGPoint(x: 1, y: 0)
        layer.colors = [
            selectedAreaColor,
            selectedAreaColor,
            nonSelectedAreaColor,
            nonSelectedAreaColor,
            selectedAreaColor,
            selectedAreaColor
        ]
        let diff = slider.maximumValue - slider.minimumValue
        var arr = [0.0] as [NSNumber]
        slider.value.forEach { (value) in
            let side1 = (value - slider.minimumValue) / diff as NSNumber
            let side2 = ((value - slider.minimumValue) / diff) / 2 as NSNumber
            arr.append(side1)
            arr.append(side2)
        }
        layer.locations = arr
        if slider.hasRoundTrackEnds{
            layer.cornerRadius = slider.trackView.frame.height / 2
        }
        slider.trackView.layer.insertSublayer(layer, at: 0)