Emitted to determine the position and size of any overlay
child widgets.
A handler for this signal should fill @allocation with
the desired position and size for @widget, relative to
the 'main' child of @overlay.
The default handler for this signal uses the @widget's
halign and valign properties to determine the position
and gives the widget its natural size (except that an
alignment of %GTK_ALIGN_FILL will cause the overlay to
be full-width/height). If the main child is a
GtkScrolledWindow, the overlays are placed relative
to its contents.
Emitted to determine the position and size of any overlay child widgets.
A handler for this signal should fill @allocation with the desired position and size for @widget, relative to the 'main' child of @overlay.
The default handler for this signal uses the @widget's halign and valign properties to determine the position and gives the widget its natural size (except that an alignment of %GTK_ALIGN_FILL will cause the overlay to be full-width/height). If the main child is a GtkScrolledWindow, the overlays are placed relative to its contents.