Remove all the old 2.x and 3.x version annotations.
GTK+ 4 is a new start, and from the perspective of a
GTK+ 4 developer all these APIs have been around since
the beginning.
Both GtkWidget and GtkContainer had similar docs regarding hfw/wfh
geometry management. Move these just to GtkWidget. Also make sure the
examples compile, port everything from gtk_preferred_* to measure and
replace some occurrences of "container" with "widget" where container
was just used to refer to a widget with child widgets.
This patch makes that work using 1 of 2 options:
1. Add all missing enums to the switch statement
or
2. Cast the switch argument to a uint to avoid having to do that (mostly
for GdkEventType).
I even found a bug while doing that: clearing a GtkImage with a surface
did not notify thae surface property.
The reason for enabling this flag even though it is tedious at times is
that it is very useful when adding values to an enum, because it makes
GTK immediately warn about all the switch statements where this enum is
relevant.
And I expect changes to enums to be frequent during the GTK4 development
cycle.
In gtk_container_real_set_focus_child(), we try to scroll to the
position of the new :focus-child if we have h or v adjustments.
gtk_widget_translate_coordinates() returns FALSE if neither widget is
realized or in other situations that cause output parameters x and y not
to be set. Thus, if the caller did not initialise x/y and uses them even
if the function returned FALSE, they are using uninitialised variables.
In gtk_container_real_set_focus_child(), we did not check the return
value but merrily went ahead and used x and y regardless. This is UB, as
revealed by Valgrind, as well as being pointless.
The trivial fix is to exit early if (!gtk_widget_translate_coordinates).
https://bugzilla.gnome.org/show_bug.cgi?id=776909
Commit 885bcd9fe4 trampled the bit here
that is meant to translate between the nominated focus child and the
actual innermost one that is used for updating the h/v adjustments.
So, we need to save the passed focus child before diving into its
children, then translate and get allocations between them both. This
makes GTK+ 4 behave like GTK+ 3 again: instead of priv->focus_child and
focus_child, we now have focus_child and child, serving the roles of the
nominated focus child and its innermost focus child respectively.
This also ditches the unnecessary call to Widget:get_focus_child(), as
Container::set_focus_child() gets that same new child as an argument.
Since setting a clip is mandatory for almost all widgets, we can as well
change the size-allocate signature to include a out_clip parameter, just
like GtkCssGadget did. And since we now always propagate baselines, we
might as well pass that one on to size-allocate.
This way we can also make sure to transform the clip returned from
size-allocate to parent-coordinates, i.e. the same coordinate space
priv->allocation is in.
The snapshot vfuncs must only append at most a single node,
otherwise things are going to break if the widget is the root node.
Unfortunately there is no code that can check this in a generic fashion,
so we'll have to debug this on a case-by-case basis.
Note that this implementation does not respect GDK windows at all. If
your widget requires respecting them, you should write your own
snapshot implementation and not chain up.
We now try to emulate cairo_t:
We keep a stack of nodes via push/pop and a transform matrix.
So whenever a new node is added to the snapshot, we transform it
by the current transform matrix and append it to the current node.
