Gtk.Button.prototype.set_relief

function set_relief(newstyle:Gtk.ReliefStyle):void {
    // Gjs wrapper for gtk_button_set_relief()
}

Sets the relief style of the edges of the given Gtk.Button widget. Three styles exist, GTK_RELIEF_NORMAL, GTK_RELIEF_HALF, GTK_RELIEF_NONE. The default style is, as one can guess, GTK_RELIEF_NORMAL.

<!-- FIXME: put pictures of each style -->