iOS Find Color at Point Between Two Colors

Question

I have a problem: I need to be able to take two colors and make a \'virtual gradient\' out of them. I then need to be able to find the color at any point on this line. My cu

Answer 1

Thanks @ramchandra-n I implemented the extension to get the intermediate color from an array of colors by percentage

extension Array where Element: UIColor {
    func intermediate(percentage: CGFloat) -> UIColor {
        let percentage = Swift.max(Swift.min(percentage, 100), 0) / 100
        switch percentage {
        case 0: return first ?? .clear
        case 1: return last ?? .clear
        default:
            let approxIndex = percentage / (1 / CGFloat(count - 1))
            let firstIndex = Int(approxIndex.rounded(.down))
            let secondIndex = Int(approxIndex.rounded(.up))
            let fallbackIndex = Int(approxIndex.rounded())

            let firstColor = self[firstIndex]
            let secondColor = self[secondIndex]
            let fallbackColor = self[fallbackIndex]

            var (r1, g1, b1, a1): (CGFloat, CGFloat, CGFloat, CGFloat) = (0, 0, 0, 0)
            var (r2, g2, b2, a2): (CGFloat, CGFloat, CGFloat, CGFloat) = (0, 0, 0, 0)
            guard firstColor.getRed(&r1, green: &g1, blue: &b1, alpha: &a1) else { return fallbackColor }
            guard secondColor.getRed(&r2, green: &g2, blue: &b2, alpha: &a2) else { return fallbackColor }

            let intermediatePercentage = approxIndex - CGFloat(firstIndex)
            return UIColor(red: CGFloat(r1 + (r2 - r1) * intermediatePercentage),
                           green: CGFloat(g1 + (g2 - g1) * intermediatePercentage),
                           blue: CGFloat(b1 + (b2 - b1) * intermediatePercentage),
                           alpha: CGFloat(a1 + (a2 - a1) * intermediatePercentage))
        }
    }
}

You can use it to get an intermediate color between two or more colors:

let color = [.green, .yellow, .red].intermediate(percentage: 70)