gtk:color-selection-current-alpha (object)

object -- a gtk:color-selection widget
alpha -- an integer for the alpha value between 0 and 65535

The accessor for the current-alpha slot of the gtk:color-selection class gets or sets the opacity. The first time this is called, it will also set the original opacity to be alpha too. This function is deprecated since version 3.4 and should not be used in newly written code.