gtk:revealer-reveal-child (object)

object -- a gtk:revealer widget
reveal -- true to reveal the child widget

The accessor for the reveal-child slot gets or sets whether the child widget is currently revealed. This function returns true as soon as the transition to the revealed state is started. To learn whether the child widget is fully revealed, that is, the transition is completed, use the gtk:revealer-child-revealed function. The transition will be animated with the current transition type of the revealer.