jimstudt

extension UIColor {
    
    // based on  http://www.zombieprototypes.com/?p=210 who looked at some data and did a bunch of curve fitting
    static func colorWithKelvin( kelvin: CGFloat) -> UIColor {
        let k = kelvin < 1000 ? 1000 : ( kelvin > 40000 ? 40000 : kelvin)
        
        func interpolate( value: CGFloat, a: CGFloat, b:CGFloat, c:CGFloat) -> CGFloat {
            return a + b*value + c*log(value)
        }