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.
| widget |
the child widget to position |
| allocation |
return location for the allocation |
|
true if the |