getWhite(_:alpha:)
Returns the grayscale and alpha values of the color.
Declaration
func getWhite(_ white: UnsafeMutablePointer<CGFloat>?, alpha: UnsafeMutablePointer<CGFloat>?)Parameters
- white:
Upon return, contains the grayscale value of the color object.
- alpha:
Upon return, contains the opacity value of the color object.
Discussion
If NULL is passed in as an argument, the method doesn’t set that value. This method works only with objects representing colors in the calibratedWhite, NSCalibratedBlackColorSpace, NSDeviceBlackColorSpace, or deviceWhite color space. Sending it to other objects raises an exception.