We were calling gtk_overlay_child_allocate() both in realize
and in add as we wanted to create and position the child windows
for the widgets. However, this call also actually called
gtk_widget_size_allocate() on the child, which it shouldn't. In some
cases the overlay is realized before being allocated, and thus it
will allocate the child at 0x0 which is an invalid size for it to be in.
In particular, if the child has margins set this will result in negative
allocations and warnings.
This fix splits out the allocation computation so that
gtk_overlay_create_child_window can use it without callers
having to call gtk_overlay_child_allocate() to move the windows.
https://bugzilla.gnome.org/show_bug.cgi?id=696623
This replaces the previously hardcoded calls to gdk_window_set_user_data,
and also lets us track which windows are a part of a widget. Old code
should continue working as is, but new features that require the
windows may not work perfectly.
We need this for the transparent widget support to work, as we need
to specially mark the windows of child widgets.
https://bugzilla.gnome.org/show_bug.cgi?id=687842
We don't get an automatic queue resize on realize anymore, which
was papering over this bug where we did not set the child window
size/position at realize time.
When we're allocating children of GtkOverlay, compare their allocation
with the overlay one, and set left/right/top/bottom style classes if the
overlaid widget touches one or more of the overlay edges.
https://bugzilla.gnome.org/show_bug.cgi?id=669342
gtk_widget_translate_coordinates() can fail in case the widget is not
realized or there's no common ancestor. Don't use the x/y values
returned by that method in that case, since their value is undefined.
Move code for child allocation into the child allocation function. Don't
keep it in the overlay allocation code.
See the next commit for why this is useful.