As it is not allowed to called gtk_extended_layout_get_desired_size()
on a GtkWidget directly; gtk_widget_get_desired_size() was really an
ambiguous api. This patch removes the added GtkWidget api, calls
the appropriate sizegroup code which in turn envokes the interface
vtable, this patch also accordingly makes GtkWidget a prerequisite
of GtkExtendedLayout (the api doesnt work for cell renderers anyway,
patch comming...).
This commit fixes the loop to take into consideration the
child->padding that will be allocated to the child while calculating
full available size. Additionally it fixes the initial positioning
of child widgets when packed at the end (a special case because the
x position used starts from the end of the box).
When doing size-requests and get_natural_size() calls, use 0 as
the base value instead of -1, because size_request code assumes
that widget->requesition is initialized at 0.
Because "size-request" signal can be handled by signal connections as well
as by third party derived classes it is necessary to always fire the
"size-request" signal for every recalculation of the widget requisition,
now gtksizegroup.c:do_size_request() fires the signal first and allows it
to overflow the minimum/natural sizes returned by extended layout
implementations.
GtkWidget->get_natural_size() is now left assigning default -1 values to
ensure they both get overridden by the size-request handling.
Getting the desired size of a GtkWidget must always be done with
gtk_widget_get_desired_size() and never with
gtk_extended_layout_get_desired_size() directly as the former passes
through size group logic and updates the widget->requisition cache.
Removed the size_request() handling on the class and calculate
minimum size from get_desired_size(); base the natural width on
either the minimum of column headers, or a greater natural request
of the columns renderers.
Applied patch to add height-for-width/width-for-height suppot
to GtkScrolledWindow plus modifications to use gtk_widget_get_desired_size()
to query children sized instead of directly calling the layout api, plus
removed the ->size_request() implementation interfering with the mess.
We should not unref the model here, it might not even exist anymore.
Instead check if it exists and only use it if it does.
The unref was leftover from a previous fix in
ba9f53397f.
Spotted by Matthias Clasen in
https://bugzilla.gnome.org/show_bug.cgi?id=614099
