The G_CONST_RETURN define in GLib is, and has always been, a bit fuzzy.
We always used it to conform to the platform, at least for public-facing
API.
At first I assumed it has something to do with brain-damaged compilers
or with weird platforms where const was not really supported; sadly,
it's something much, much worse: it's a define that can be toggled at
compile-time to remove const from the signature of public API. This is a
truly terrifying feature that I assume was added in the past century,
and whose inception clearly had something to do with massive doses of
absynthe and opium — because any other explanation would make the
existence of such a feature even worse than assuming drugs had anything
to do with it.
Anyway, and pleasing the gods, this dubious feature is being
removed/deprecated in GLib; see bug:
https://bugzilla.gnome.org/show_bug.cgi?id=644611
Before deprecation, though, we should just remove its usage from the
whole API. We should especially remove its usage from Cally's internals,
since there it never made sense in the first place.
GCC can catch errors when it knows that a variadic function must be
ended with NULL. Let's use the glib macro encapsulating the GCC
attribute to clutter_animator_set() and clutter_state_set().
A bogus ClutterInterpolation argument had been carried from
clutter_animator_set_interpolation to clutter_animator_get_interpolation
in copy and paste.
When asking a key for its target value we also ask the developer to pass
in an initialized GValue - but we don't make it easy to know the type of
the GValue. A developer has to ask the GObject class for the GParamSpec
and then initialize the GValue, instead.
Since we know the type of the GValue we should provide a getter for it.
We should also allow developers to throw at us GValue with compatible and
transformable types.
Finally, all the accessors should be constified.
ClutterAnimator is a class for managing the animation of multiple
properties of multiple actors over time with keyframing of values.
The Animator class is meant to be used to effectively describe
animations using the ClutterScript definition format, and to construct
complex implicit animations from the ground up.
Signed-off-by: Emmanuele Bassi <ebassi@linux.intel.com>