Gtk.Tooltip.prototype.set_icon

function set_icon(pixbuf:GdkPixbuf.Pixbuf):void {
    // Gjs wrapper for gtk_tooltip_set_icon()
}

Sets the icon of the tooltip (which is in front of the text) to be pixbuf. If pixbuf is null, the image will be hidden.

Since 2.12

pixbuf

a GdkPixbuf.Pixbuf, or null