CAGradient using UIColor array

Question

I have iCarousel set up to display a series of gradients.

    // Set gradient colours
    var gradientColours = [

    // First gradient
    UIColor(red:0.33, green:0.38, blue:0.44, alpha:1.0),
    UIColor(red:1.00, green:0.42, blue:0.42, alpha:1.0),

    //Second gradient
    UIColor(red:0.08, green:0.12, blue:0.19, alpha:1.0),
    UIColor(red:0.14, green:0.23, blue:0.33, alpha:1.0),

    // Third gradient
    UIColor(red:0.83, green:0.84, blue:0.16, alpha:1.0),
    UIColor(red:0.83, green:0.84, blue:0.16, alpha:1.0),

    // Fourth gradient
    UIColor(red:0.12, green:0.11, blue:0.09, alpha:1.0),
    UIColor(red:0.56, green:0.05, blue:0.00, alpha:1.0),

    // Fifth gradient
    UIColor(red:0.09, green:0.75, blue:0.99, alpha:1.0),
    UIColor(red:0.80, green:0.19, blue:0.40, alpha:1.0)]

    func carousel(_ carousel: iCarousel, viewForItemAt index: Int, reusing view: UIView?) -> UIView {
    let frontView = UIView(frame: CGRect(x: 0, y: 0, width: 300, height: 200))
    frontView.contentMode = .center

    frontView.layer.cornerRadius = 15;
    frontView.layer.masksToBounds = true;

    let gradient = CAGradientLayer()
    gradient.frame = frontView.bounds
    gradient.startPoint = CGPoint(x: 0.0, y: 0.0)
    gradient.endPoint = CGPoint(x: 1.0, y: 1.0)

    gradient.colors = [gradientColours[index].cgColor, gradientColours[index+1].cgColor]

    frontView.layer.addSublayer(gradient)
    return frontView

The problem is, the first gradient is fine as it uses gradientColours[0] and gradientColours1, but any other ones after that don't work as they use 1 and 2, 2 and [3] and so on...

I feel as though this has an obvious answer but I cannot think of it at the moment...

Thanks for the help.

Edit: Images for clarity:

First gradient works fine:

First gradient works fine: Second gradient takes first colour value from previous gradient:

Answer 1

I have solution for this by using simple odd/Even Logic see the below program

 import Foundation
var gradientColours = [

    // First gradient
    UIColor(red:0.33, green:0.38, blue:0.44, alpha:1.0),
    UIColor(red:1.00, green:0.42, blue:0.42, alpha:1.0),

    //Second gradient
    UIColor(red:0.08, green:0.12, blue:0.19, alpha:1.0),
    UIColor(red:0.14, green:0.23, blue:0.33, alpha:1.0),

    // Third gradient
    UIColor(red:0.83, green:0.84, blue:0.16, alpha:1.0),
    UIColor(red:0.83, green:0.84, blue:0.16, alpha:1.0),

    // Fourth gradient
    UIColor(red:0.12, green:0.11, blue:0.09, alpha:1.0),
    UIColor(red:0.56, green:0.05, blue:0.00, alpha:1.0),

    // Fifth gradient
    UIColor(red:0.09, green:0.75, blue:0.99, alpha:1.0),
    UIColor(red:0.80, green:0.19, blue:0.40, alpha:1.0)]

       var indexOfGradientColor = 0

     func carousel(_ carousel: iCarousel, viewForItemAt index: Int, reusing view: UIView?) -> UIView
     {
        let frontView = UIView(frame: CGRect(x: 0, y: 0, width: 300, height: 200))
        frontView.contentMode = .center

        frontView.layer.cornerRadius = 15;
        frontView.layer.masksToBounds = true;

        let gradient = CAGradientLayer()
        gradient.frame = frontView.bounds
        gradient.startPoint = CGPoint(x: 0.0, y: 0.0)
        gradient.endPoint = CGPoint(x: 1.0, y: 1.0)

        if (indexOfGradientColor%2 == 0)
        {
            gradient.colors = [gradientColours[indexOfGradientColor].cgColor, gradientColours[indexOfGradientColor+1].cgColor]

        }
        else
        { gradient.colors = [gradientColours[indexOfGradientColor+1].cgColor, gradientColours[indexOfGradientColor+2].cgColor]}
        if indexOfGradientColor < (gradientColours.count-2)
        {
                indexOfGradientColor += 2
        }
        else
        {
            indexOfGradientColor = 0
        }

        frontView.layer.addSublayer(gradient)
        return frontView
    }