Color Helpers iOS

Color+lerp.swift

extension Double {
    func interpolated(to b: Double, at t: Double) -> Double {
        self + (b - self) * (t * t)
    }
}

extension [Color] {
    func rgbaLerp(at t: Double) -> Color {
        let position = t * Double(count - 1)
        let i = Int(position)
        let t = CGFloat(position - Double(i))
        return self[i].rgbaLerp(to: self[i + 1], t)
    }
}

extension [Color] {
    func hsbaLerp(at t: Double) -> Color {
        let position = t * Double(count - 1)
        let i = Int(position)
        let t = CGFloat(position - Double(i))
        return self[i].hsbaLerp(to: self[i + 1], t)
    }
}

extension Color {
    func rgbaLerp(to endColor: Color, _ t: CGFloat) -> Color {
        let a = rgba
        let b = endColor.rgba

        let red   = a.r.interpolated(to: b.r, at: t)
        let green = a.g.interpolated(to: b.g, at: t)
        let blue  = a.b.interpolated(to: b.b, at: t)
        let alpha = a.a.interpolated(to: b.a, at: t)

        return Color(red: Double(red), green: Double(green), blue: Double(blue), opacity: Double(alpha))
    }
}

extension Color {
    func hsbaLerp(to endColor: Color, _ t: CGFloat) -> Color {
        let a = hsba
        let b = endColor.hsba

        let hue   = a.h.interpolated(to: b.h, at: t)
        let saturation = a.s.interpolated(to: b.s, at: t)
        let brightness  = a.b.interpolated(to: b.b, at: t)
        let alpha = a.a.interpolated(to: b.a, at: t)

        return Color(hue: hue, saturation: saturation, brightness: brightness, opacity: alpha)
    }
}

#if canImport(UIKit)
import UIKit
typealias PlatformColor = UIColor
#endif

#if canImport(AppKit)
import AppKit
typealias PlatformColor = NSColor
#endif

extension Color {
    var rgba: (r: Double, g: Double, b: Double, a: Double) {
        var red: CGFloat = 0
        var green: CGFloat = 0
        var blue: CGFloat = 0
        var alpha: CGFloat = 0

        var platformColor = PlatformColor(self)

#if canImport(AppKit)
        platformColor = platformColor.usingColorSpace(.deviceRGB) ?? PlatformColor(self)
#endif
        platformColor.getRed(
            &red,
            green: &green,
            blue: &blue,
            alpha: &alpha
        )

        return (
            r: Double(red),
            g: Double(green),
            b: Double(blue),
            a: Double(alpha)
        )
    }

    var rgb: (r: Double, g: Double, b: Double) {
        (
            r: rgba.r,
            g: rgba.g,
            b: rgba.b
        )
    }
}

extension Color {
    var hsba: (h: Double, s: Double, b: Double, a: Double) {
        var hue: CGFloat = 0
        var saturation: CGFloat = 0
        var brightness: CGFloat = 0
        var alpha: CGFloat = 0

        var platformColor = PlatformColor(self)

#if canImport(AppKit)
        platformColor = platformColor.usingColorSpace(.deviceRGB) ?? PlatformColor(self)
#endif
        platformColor.getHue(
            &hue,
            saturation: &saturation,
            brightness: &brightness,
            alpha: &alpha
        )

        return (
            h: Double(hue),
            s: Double(saturation),
            b: Double(brightness),
            a: Double(alpha)
        )
    }

    var hsb: (h: Double, s: Double, b: Double) {
        (
            h: hsba.h,
            s: hsba.s,
            b: hsba.b
        )
    }
}