Designable from storyboard, reusable vertical slider

CCVerticalSlider.swift

import UIKit

protocol VerticalSliderDelegate: class {
    
    func sliderValueIsChanged(_ verticalSlider: CCVerticalSlider, value: CGFloat)
}

@IBDesignable open class CCVerticalSlider: UIView {

    let shapeLayer = CAShapeLayer()
    var delegate: VerticalSliderDelegate?
    internal let slider = CCustomSlider()

    // required for IBDesignable class to properly render
    required public init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)

        initialize()
    }

    // required for IBDesignable class to properly render
    required override public init(frame: CGRect) {
        super.init(frame: frame)

        initialize()
    }

    fileprivate func initialize() {
        
        updateSlider()
        addSubview(slider)
    }

    fileprivate func updateSlider() {
        if !ascending {
            slider.transform = CGAffineTransform(rotationAngle: CGFloat(Double.pi) * -0.5)
        } else {
            slider.transform = CGAffineTransform(rotationAngle: CGFloat(Double.pi) * 0.5).scaledBy(x: 1, y: -1)
        }

        slider.minimumValue = minimumValue
        slider.maximumValue = maximumValue
        slider.value = value
        slider.thumbTintColor = thumbTintColor
        slider.minimumTrackTintColor = minimumTrackTintColor
        slider.maximumTrackTintColor = maximumTrackTintColor
        slider.isContinuous = isContinuous
        slider.trackWidth = self.trackWidth

        slider.layer.cornerRadius = self.cornersRadius
        
        let rectangle = CGRect(x: 0, y: 0, width: self.bounds.width, height: self.bounds.height)
        let roundedRectPath = UIBezierPath(roundedRect: rectangle, byRoundingCorners: .allCorners, cornerRadii: CGSize(width: self.cornersRadius, height: self.cornersRadius))
        
        shapeLayer.path = roundedRectPath.cgPath
        shapeLayer.strokeColor = self.borderColor?.cgColor
        shapeLayer.fillColor = UIColor.clear.cgColor
        shapeLayer.lineCap = .round
        shapeLayer.lineJoin = .round
        shapeLayer.lineWidth = 0.3
        
        self.layer.insertSublayer(shapeLayer, below: slider.layer)
        self.layer.cornerRadius = self.cornersRadius
        
        slider.addTarget(self, action: #selector(sliderValueChanged(_:)), for: .valueChanged)
    }

    @IBInspectable open var ascending: Bool = false {
        didSet {
            updateSlider()
        }
    }

    override open func layoutSubviews() {
        super.layoutSubviews()

        slider.bounds.size.width = bounds.height - 6
        slider.bounds.size.height = bounds.width
        slider.center.x = self.bounds.midX + 3
        slider.center.y = self.bounds.midY
    }

    override open var intrinsicContentSize: CGSize {
        get {
            return CGSize(width: slider.intrinsicContentSize.height, height: slider.intrinsicContentSize.width)
        }
    }

    @IBInspectable open var minimumValue: Float = -1 {
        didSet {
            updateSlider()
        }
    }

    @IBInspectable open var maximumValue: Float = 1 {
        didSet {
            updateSlider()
        }
    }

    @IBInspectable open var value: Float {
        get {
            return slider.value
        }
        set {
            slider.setValue(newValue, animated: true)
        }
    }

    @IBInspectable open var thumbTintColor: UIColor? {
        didSet {
            updateSlider()
        }
    }

    @IBInspectable open var minimumTrackTintColor: UIColor? {
        didSet {
            updateSlider()
        }
    }

    @IBInspectable open var maximumTrackTintColor: UIColor? {
        didSet {
            updateSlider()
        }
    }
    
    @IBInspectable open var borderColor: UIColor? {
        didSet {
            updateSlider()
        }
    }

    @IBInspectable open var trackWidth: CGFloat = 10 {
        didSet {
            updateSlider()
        }
    }
    
    @IBInspectable open var cornersRadius: CGFloat = 5 {
        didSet {
            updateSlider()
        }
    }
    
    @IBInspectable open var isContinuous: Bool = true {
        didSet {
            updateSlider()
        }
    }
    
    @objc fileprivate func sliderValueChanged(_ sender: UISlider) {
        delegate?.sliderValueIsChanged(self, value: CGFloat(sender.value))
    }
}

class CCustomSlider: UISlider {
        
    @IBInspectable var trackWidth: CGFloat = 20
    
    override func trackRect(forBounds bounds: CGRect) -> CGRect {
        return CGRect(origin: bounds.origin, size: CGSize(width: bounds.width, height: trackWidth))
    }
}