flashScreen.swift

func flashScreen() {
        let inDuration  : CGDisplayFadeInterval = 0.5
        let outDuration : CGDisplayFadeInterval = 0.5
        let redColor    = NSColor.red

        var token : CGDisplayFadeReservationToken = UInt32(kCGDisplayFadeReservationInvalidToken)
        let color = redColor.usingColorSpace(NSColorSpace.sRGB)!

        if CGAcquireDisplayFadeReservation(inDuration + outDuration, &token) == CGError.success {
            CGDisplayFade(token,
                          inDuration,
                          0.0 as CGDisplayBlendFraction,
                          0.2 as CGDisplayBlendFraction,
                          Float(color.redComponent),
                          Float(color.greenComponent),
                          Float(color.blueComponent),
                          boolean_t(1))
            CGDisplayFade(token,
                          inDuration,
                          0.2 as CGDisplayBlendFraction,
                          0.0 as CGDisplayBlendFraction,
                          Float(color.redComponent),
                          Float(color.greenComponent),
                          Float(color.blueComponent),
                          boolean_t(1))
            CGReleaseDisplayFadeReservation(token)
        }
    }