// returns true if color is light, false if it is dark
extension UIColor
{
    func isLight() -> Bool
    {
        // algorithm from: http://www.w3.org/WAI/ER/WD-AERT/#color-contrast
        let components = CGColorGetComponents(self.CGColor)
        let brightness = ((components[0] * 299) + (components[1] * 587) + (components[2] * 114)) / 1000

        if brightness < 0.5
        {
            return false
        }
        else
        {
            return true
        }
    }
}