How to compare for nearly equal in Swift

Issue #607

Implement Equatable and Comparable and use round

struct RGBA: Equatable, Comparable {
    let red: CGFloat
    let green: CGFloat
    let blue: CGFloat
    let alpha: CGFloat

    init(_ red: CGFloat, _ green: CGFloat, _ blue: CGFloat, _ alpha: CGFloat) {
        self.red = red
        self.green = green
        self.blue = blue
        self.alpha = alpha
    }

    static func round(_ value: CGFloat) -> CGFloat {
        (value * 100).rounded() / 100
    }

    static func == (left: RGBA, right: RGBA) -> Bool {
        let r = Self.round
        return r(left.red) == r(right.red)
            && r(left.green) == r(right.green)
            && r(left.blue) == r(right.blue)
            && r(left.alpha) == r(right.alpha)
    }

    static func < (left: RGBA, right: RGBA) -> Bool {
        let r = Self.round
        return r(left.red) < r(right.red)
            && r(left.green) < r(right.green)
            && r(left.blue) < r(right.blue)
            && r(left.alpha) <= r(right.alpha)
    }
}

XCTAssertGreaterThan(backgroundRgba, RGBA(0.57, 0.12, 0.88, 1.0)
XCTAssertLessThanThan(backgroundRgba, RGBA(0.57, 0.12, 0.88, 1.0)